Bangabandhu Sheikh Mujibur Rahman Agricultural University in partial. Fulfillment .... Serial No. Title. Page No. 1. Various panicle colors in exotic rice genotype.
CHARACTERIZATION AND GENETIC DIVERSITY FOR AGRONOMIC TRAITS IN EXOTIC RICE
S. M. ABDULLAH AL MAMUN REGISTRATION NO. 2008-08-2152
A THESIS Submitted To
Bangabandhu Sheikh Mujibur Rahman Agricultural University in partial Fulfillment of the requirement for the degree of
MASTER OF SCIENCE IN GENETICS AND PLANT BREEDING
SUMMER, 2011 1
ACKNOWLEDGEMENTS First of all, the author wish to express all his devotion and reverence to the Almighty Allah, most merciful beneficent creator who always helps for facing any difficulty and has enabled him to complete the research work and to prepare the thesis for the fulfillment of the M.S. degree. The author would like to express gratitude and appreciation to his honorable Major Professor and Chairman of advisory committee Dr. Nasrin Akter Ivy, Associate professor and Head, Department of Genetics and Plant breeding, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Salna, Gazipur, for her adept guidance, supervision, valuable suggestions, constant encouragement and constructive criticism in completing the research work and preparation of this thesis. The author would like to express his gratefulness and deepest gratitude to Prof. Dr. Md. Golam Rasul, Dept. of Genetics and Plant Breeding and Prof. Dr. M. Mofazzal Hossain, Dept. of Horticulture, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Salna, Gazipur, members of the advisory committee for their valuable advice, suggestions, instructions, constructive criticisms during the analysis of data and writing this thesis. The author expresses his thanks to Mr. M. Akbar Ali, Demonstrator, Mr. Abdul Hamid, Mr. Md. Rafique and all other field and laboratory staff of the Dept. of Genetics and Plant Breeding for their kind co-operation towards the completion of the research work. The author would like to express his deepest gratitude and indebtedness to his beloved parents whose blessing, sacrifices, constant encouragement, inspiration and dedicated efforts enabled to educate him up to this level. Lastly the author can not but express his heartful gratitude and indebtedness to his all friends and well-wisher for their cooperation and help during the research work. He is especially thankful to Farjana Parvin, Ariful Islam, Shibly Noman, Tania Akter and many others who heavily encouraged him to undertake and complete this research work. BSMRAU, Gazipur Summer, 2011
The Author
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THESIS ABSTRACT CHARACTERIZATION AND GENETIC DIVERSITY FOR AGRONOMIC TRAITS IN EXOTIC RICE BY S. M. ABDULLAH AL MAMUN
Fifty two exotic rice including two check varieties were evaluated to characterize and find out the genetic variability, character association, path coefficient and genetic divergence for agronomic traits. The analysis of variance showed significant variation for all the characters indicating wide genetic variability among the genotypes. The genotypes RG-BU-08-072 showed dark red and RGBU-08-076, 80, 82 and 99 showed light red panicle in colour. The genotypes RG-BU-08-072, 76, 78, 79, 82, 91 and 99 showed closed panicle type. The genotypes RG-BU-08-052, 54, 58, 62, 65, 66, 68, 69, 70, 73, 74, 75, 80, 84, 90, 92, 95 and 97 showed intermediate panicle type and remaining genotypes showed open type panicle. The genotypes RG-BU-08-099 and RG-BU-08-096 showed the highest and the lowest seed length respectively. The genotypes RG-BU-08-099 showed the highest seed breadth and genotype RG-BU-08-087 had the lowest seed breadth. The highest pollen sterility was recorded in the genotypes RG-BU-08-062 and 69. The highest grain yield per hill produced by the genotype RG-BU-08-071. The highest genotypic variance and phenotypic variance were found for filled grains per panicle, pollen sterility and spikelet sterility. High heritability and genetic advance were recorded for days to harvesting, pollen sterility, days to 50% flowering and days to first flowering. Days to first flowering, days to harvesting, pollen sterility, filled grains per panicle and grain length of different genotypes had a high degree of significant positive association with grain yield per hill and also showed that these characters had the major contribution towards grain yield per plant. Diversity analysis revealed that the genotypes were grouped into seven clusters. The highest inter genotypic distance was 6.448 which was observed between RG-BU-08-085 and 69. The highest inter-cluster distance was recorded between cluster V and VI (36.37). The genotypes RG-BU-08-051, 61, 65, 67, 69, 71, 85, 86, 88, 94, 9, 98 and 99 may be used as divergent parent in future hybridization programme.
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TABLE OF CONTENTS
Serial No.
Contents
Page No.
ABSTRACT
v
ACKNOWLEDGEMENT
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
viii
LIST OF FIGURES
ix
LIST OF APPENDICES
ix
I
INTRODUCT`ION
1-3
II
REVIEW OF LITERATURE
4-20
III
MATERIALS AND METHODS
21-32
IV
RESULTS AND DISCUSSION
33-72
V
SUMMERY
73-75
VI
CONCLUSION AND RECOMMENDATION
76-77
VII
REFERENCES
78-88
APPENDICES
89-95
CHAPTER
4
LIST OF TABLES
Serial No. Title 1 Various specialties of different exotic rice genotypes 2
Pollen sterility and spikelet sterility status of different exotic rice genotypes
3
Analysis of variance for16 characters of 50 of exotic rice genotypes with two check
Page No. 34-35 41-42 44
varieties 4
Varietal Differences in 16 characters of 50 exotic rice genotypes with two check
45
varieties 5
Estimation of genetic parameters of 50 exotic rice genotypes with two check
52
varieties 6
Genotypic (rg) and phenotypic (rp) Correlation coefficient among 50 exotic rice
55
genotypes with two check varieties 7
Partitioning of genotypic correlation with grain yield into direct (bold) and indirect
57
effect in 50 exotic rice genotypes with two check varieties 8
Latent roots (Eigen values) and percentage of variation for corresponding 16
60
components characters in 50 exotic rice genotypes with two check varieties 9
Distribution of 50 exotic rice genotypes with 2 check varieties in seven clusters
63
10
Ten higher and ten lower inter genotypic distance among the 50 exotic rice
65
genotypes with two check varieties 11
Average intra (Diagonal) and intercluster distances (D2) of 50 exotic rice genotypes
67
with two check varieties 12
Cluster mean for 16 characters in 50 exotic rice genotypes with two check varieties
69
13
Latent vectors for 16 characters of 50 exotic rice genotypes with two check
71
varieties 5
LIST OF FIGURES
Serial No.
Title
Page No.
1
Various panicle colors in exotic rice genotype
36-37
2
Figure shows various panicle type in exotic rice genotype
38
3
Figure shows various seed shape and seed colour in exotic rice genotypes
39
4
Path diagram of reproductive characters on grain yield per hill
58
5
Scatter diagram of 50 exotic rice genotypes with 2 check varieties based on their principal component scores
61
6
Scatter diagram of 50 exotic rice genotypes with 2 check varieties based on their principal component scores superimposed with clustering
62
LIST OF APPENDICES
Appendices
Contents
Page No.
I
Composition of Staple Food Rice
90
II
Temperature, relative humidity and rainfall during the growing period of rice Mean performance of 50 exotic rice genotypes and two check variety based on different reproductive traits related to yield
91
III IV
Principal component scores 50 exotic rice genotypes with 2 check varieties
6
92-94 95-96
CHAPTER I INTRODUCTION Rice (Oryza sativa L.) is a cereal crop belonging to the family Gramineae (Poaceae) having chromosome number 2n=24 under the order Cyperales and class Monocotyledon. It is a self pollinated crop, although outcrossing to an extent of 6.8% has been reported in some varieties under certain condition. Inflorescence of rice is a terminal panicle with single flowered spikelets. The Genus Oryza includes a total of 22 to 27 species out of which only two are cultivated. The two cultivated species are Oryza sativa (Asian rice) and Oryza glaberrima (African rice). Oryza sativa originated from Indo-china region i.e., Assam, Bangladesh, Burma, Thailand, Laos and Vietnam where as Oryza glaberrima from Africa (West Africa and southern Sahara). Asia is traditionally rich in the diversity of rice including the wild progenitors of cultivated rice (Singh et al., 2001). Rice is a major food crop for the people of the world in general and Asians in particular; nearly 90% of the world's rice is produced and consumed in this region. It is estimated that half of the world’s population subsists wholly or partially on rice. Bangladesh agricultural economy predominantly based on rice production. Rice occupies about 75% of the total cropped area and constitutes 94% of cereals production (Anonymous, 1999). In Bangladesh total production area of rice is 64.63 lac ha and total production is 125.55 million metric tones (Anonymous, 2005). Two-third of Bangladesh populations
is
engaged
in
livelihood
activities
(http//.asiarice.org./asiarice/demosite/sections/chapters/Bangladesh/
related BRF).
It
to is
rice. high
in
carbohydrates, low in fat, and rich in proteins, vitamins and minerals (Appendix-I). The world population expected to reach 8 billion in 2025 and 8-9 billion by the year 2030 from the present state of 5-8 billion (Brown, 1994). Facing the challenge of population growth and cropland reduction, it
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is obvious that the only way to solve this problem is to improve the yield of cereal crops namely, rice, wheat and corn etc. (Yuan and Peng, 2005). The need for expansion of rice cultivation does not only depend on cultural practices and management, but also on the suitability of rice varieties, which must be drawn from existing germplasm that has been collected and conserved by genetic resources centers (Ng et al., 1988). Cytoplasmic male sterility and photo/thermo-sensitive male sterility, respectively has now become the primary means to increase grain yield of rice. Panicle characters represent the most important reproductive traits of rice in respect of yield improvement. The yield potentials of these rice varieties vary due to the architecture of panicle. Yield increase in modern rice was possible through improvement of panicle characters viz, long panicles, high number of filled grains, more primary and secondary rachis, etc. (Seetharaman et al., 1973). Hence, apart from yield and its component characters, emphasis should be given on agronomic traits like panicle characters. But improvement of panicle characters requires investigation on their genetic system. Information on mode of inheritance and nature of genetic components of panicle characters in rice are very scanty (Mahmood et al., 2004; Chang et al., 1998). Cultivated rice is endowed with a rich genetic variability. In spite of such a great diversity, the modern rice cultivars have narrow genetic base for most of the agronomically important traits. To sustain the demand of an ever increasing population, new avenues have to be explored to increase the yield of rice. Exotic species present potential donor sources for complex traits such as yield and would help to realize the dream of sustained food security. Characterization and evaluation of potential varieties should form an important constituent of these collection efforts because of their in-built genetic variability due to several generations of growing and selection by breeders and farmers. However, the utilization of these rice genetic resources had been limited to only adaptable genotypes (Caldo et al., 1996). As a result, the diversity of these genetic resources is being lost to 8
the need for higher yields and early maturity. However, a successful breeding program will depend on the genetic diversity of a crop for achieving the goals of improving the crop and producing high yielding and better resistant varieties (Padulosi, 1993). Therefore, there is the need to diversify the genetic base of improved rice varieties, and the first step towards this is to evaluate and characterize agronomic traits of available rice germplasm. This is because the evaluation of phenotypic diversity usually reveals important traits of interest to plant breeders (Singh and Rachie, 1985). The success of any plant breeding programme aimed at the evolution of high yielding, better quality and disease resistant varieties depends upon the selection of suitable genotypes to be utilized in breeding programme. The study of genetic diversity among genotypes is helpful in formulating effective crop breeding strategy. Despite the importance of characterization and the data produced by this process, very little work has been done. More information and research is required on these aspects. The present investigation has been undertaken with an attempt to study the mode of inheritance and nature of genetic components of agronomic traits of exotic rice germplasm. Therefore, the present study was conducted on following objectives: To study the genetic variability and character association of agronomic traits among exotic rice germplasm To characterize suitable genotype among exotic rice germplasm and identifying the male sterile genotypes and To search suitable diverse germplasm as suitable donor parents for the utilization in future breeding program.
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CHAPTER II REVIEW OF LITERATURE The identification of suitable parental lines on the basis of their genetic parameter, nature and magnitude of genetic variability, the correlation and genetic diversity of different yield attributing characters are important for successful rice breeding programs. The present study has aimed at studying the variability, heritability, genetic advanced, genetic diversity association among characters and yield related characters among the exotic rice genotypes. The available information relevant to the present study has been reviewed in this chapter.
2.1 Variation for yield and yield contributing characters 2.1.1 Days to 50% flowering Sanjeev (2005) conducted an experiment with 19 mutant lines (M 3) derived from pusa Basmati and Taraori Basmati and observed higher heritability for days to flowering compared to other characters. Satyanarayana et al. (2005) studied variability, correlation and path co-efficient analysis for 66 restorer lines in rice and observed high variability, heritability and genetic advance for days to 50% flowering. Singh et al. (2006) evaluated the genetic variability, heritability, genetic advance and character association in 37 rice genotypes. The estimates of phenotypic co-efficient of variation and genotypic co-efficient of variation were of the same magnitude for plant height except fertility percentage. Days to 50% flowering exhibited the highest heritability estimates. High heritability accompanied by moderate genetic advance was recorded for days to 50% flowering.
10
Sankar et al. (2006) studies on variability and correlation in 34 rice genotypes, high heritability and genetic advance were obtained for days to 50% flowering, plant height. Positive and significant correlation was reported with days to 50% flowering and productive tiller per plant. Sanjeev Kumar et al. (2007) studied the gene action for grain yield, components and quality traits in 9 parental genotypes hybrids of rice grown in Himachal Pradesh, India, during the kharif of 2003. The additive and non-additive components were significant for, number of days to 50% flowering. Adil Jamal et al. (2007) studied the eight rice genotypes including six hybrids (HR-41, HR-30, HR9, HR-10, Arize-403, Dagha-1, KS 282 and Bas-385) in Pakistan to observe genetic variability among different plant traits contributing to yield. A significant negative correlation was obtained between days to 50% flowering and grain yield per plant. Kishore et al. (2007) conducted an experiment during kharif 2004 in Hyderabad, Andhra Pradesh, India, with 70 rice genotypes, including aromatic and non -aromatic lines. Observations were recorded on days to 50% flowering. Path co-efficient analysis revealed that day to 50% flowering showed positive direct effects on grain yield. 2.1.2 Number of filled grains per panicle Sanjeev (2005) studied 19 mutant lines derived form two Basmati rice and observed maximum amount of variability for number of grains per panicle. High heritability coupled with high genetic advance was also observed for this character. Satyanarayana et al. (2005) studied variability, correlation and path co-efficient analysis for 66 restorer lines in rice and observed high variability, heritability and genetic advance for number of grains per panicle.
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Patil and Sarawgi (2005) studied genetic variability in traditional aromatic rice accessions and found that the genetic and phenotypic co-efficient of variation were high for number of filled grains per panicle. Singh et al. (2006) conducted an experiment with 37 rice genotypes and reported that there were highly significant differences among the genotypes for number of grains per panicle and the estimates of phenotypic co-efficient of variation and genotypic co-efficient of variation were of the same magnitude for the character. High heritability was recorded for the characters. Sankar et al. (2006) conducted an experiment with 34 rice genotypes and high heritability as well as genetic advance was obtained for grains per panicle. 2.1.3 Pollen sterility and spikelet sterility percentage Patil and Sarawgi (2005) conducted and experiment with 128 aromatic rice accessions and observed high genotypic and phenotypic co-efficient of variation of unfilled grains per panicle and percentage of unfilled grain. High heritability coupled with high genetic advance was also found for this character. Satyanarayana et al. (2005) studied variability, correlation and path co-efficient analysis for 66 restorer lines in rice and observed high variability, heritability and genetic advance for spike let fertility. Patil and Sarawgi (2005) studied genetic variability in traditional aromatic rice accessions and found that the genetic and phenotypic co-efficient of variation were high for number of unfilled grains per panicle, unfilled grain percentage Singh et al. (2006) conducted an experiment with 37 rice genotypes and reported that there were highly significant differences among the genotypes for fertility percentage and the estimates of 12
phenotypic co-efficient of variation and genotypic co-efficient of variation were of same magnitude for the character. 2.1.4 Out crossing rate percentage Islam et al. (2005) field experiments were conducted in Gazipur, Bangladesh, during the 2001 wet and 2002 dry seasons, to determine the effect of flag leaf clipping and gibberellic acid (GA 3) application on hybrid rice seed yield. The outcrossing rate in the dry and wet seasons was highest in T4. The highest seed yield was also observed in T4 during the dry season, while there were no significant differences in seed yield among the different treatments during the wet season. 2.1.5 Grain yield per hill Honarnejad and Tarang (2001) evaluated seven local and alien rice cultivars for traits grain yield and other contributing characters. They observed 46% narrow sense heritability for grain yield. Shanthi and Singh (2001) studied 16 M6 generation of induced mutant along with non-mutant Mahsuri for variation in yield and yield component and found significant variation among the genotypes for all characters studied. Heritability in broad sense was high (more than 80%) for all characters expect grain yield per plant (78.99). Pandey and Awasthi (2002) studied genetic variability in 21 genotypes of aromatic rice for yield contributing traits. Significant genetic variability was observed among the 21 genotypes for the entire yield contributing traits. They concluded that traits plant height, days to 50% flowering, effective tillers per plant, panicle length, number of grains per panicle, grain weight and grain yield per plant play major roles in the enhancement of grain production.
13
Sinha et al. (2004) evaluated 19 mid land rice land races and found high heritability coupled with high genetic advance for grain yield followed by test weight and panicles per plant. A high genotypic and phenotypic co-efficient of variation was also observed for this character. Battan et al. (2006) studied 25 rice genotypes and observed high co-efficient of variation (GCV) and phenotypic co-efficient of variation (PCV) coupled with high heritability indicating further scope of improvement in this character grain yield per plant through selection.
2.2 Relationship between yield and yield contributing characters Grain yield is associated with many yield contributing characters. The major yield components in rice have been identified as number of panicles per plant; number of grain per plant and average grain weight. In addition there are other characters plant height, days to maturity, panicle length etc. which contribute to grain yield. Association of yield contributing characters with grain yield in rice was comprehensively studied by many breeders and based on their results they formulated different selection criteria for yield improvement. Association of yield contributing characters with yield was studied at both genotypic and phenotypic levels. Usually, it was observed that genotypic correlation co-efficient were higher than the phenotypic correlation co-efficient. Some of the important findings those are relevant to correlation study are reviewed here2.2.1 Variability Banumathy et al. (2002) evaluated ten cytoplasmic male sterile (CMS) lines for genetic variability for 8 floral traits and their association with outcrossing rate. Genetic variability analysis revealed narrow difference between phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) for all the traits. The genetic parameters, PCV, GCV, heritability and genetic 14
advance, were also high for these traits indicating the preponderance of additive gene effects in the inheritance of these traits. The CMS line IR 68281A which had maximum outcrossing rate possessed maximum percentage of exserted stigma. Similarly, IR 68885A with large stigmatic area and maximum style length also recorded high seed set percentage on outcrossing. Chang-JaeKi et al. (2002) tested two rice cultivars, 'Oochikara' with large grain and 'Hwayeongbyeo' and their progenies (F1, F2, B1, and B2) to understand gene action of morphological traits of rice grain and their relationships. The evaluated traits were 1000-grain weight, grain length, width, thickness, length-width ratio, and chalkiness of brown rice. Correlation between grain weight and chalkiness was highly significant in the all progenies, and grain length was not associated with width and thickness in an F2 population. Scaling test and joint scaling test revealed that inheritance of grain traits were fitted to additive-dominance model without epistasis. Additive effects for the traits were much greater than the dominance effects. Abdel-Ghani et al. (2005) investigated the genetic variability and correlation coefficients involving five floral characters in a group of 29 cultivated and wild rice (Oryza sp.). Wide variability existed in anther length, stigma length and percent exerted stigma. The genetic variation constituted a high proportion of the total variation for these traits. Thus, selection for these characters is expected to be highly effective. Ordonez et al. (2005) studied the genetic variability of restorer for the development of three-line rice hybrids involving 20 randomly selected restorer lines and three commercially usable CMS lines. Estimates of genetic variance of restorer lines for days to 50% flowering, plant height (cm), grain yield per ha, panicle length (cm), number of spikelets per panicle, percent filled grains and 1000grain weight (g) were highly significant but not for number of productive tillers. Confidence interval estimates for all traits were also significantly different from zero, except for number of productive 15
tillers, indicating substantial genetic variability for these traits. Combined mean performance across locations revealed several hybrids out-yielding the best check varieties. Madhavilatha et al. (2005) were evaluated fifty-four elite rice genotypes in Tirupati, Andhra Pradesh, India, during rabi 2001-02 for their variability with regards to grain yield, yield components (plant height, number of effective tillers per plant, panicle length, number of grains per panicle, fertility percentage, days to 50% flowering, days to maturity and harvest index) and quality parameters (kernel length (L), breadth (B), L/B ratio and elongation ratio, 1000-grain weight etc.). The results revealed high variability, heritability and genetic advance for number of grains per panicle, grain yield per plant, harvest index and kernel L/B ratio, while days to maturity, fertility percentage, hulling recovery and kernel elongation ratio had high heritability coupled with low genetic advance indicating the need for emphasis on these traits during selections for yield improvement. Kumar et al. (2006) was conducted a study in Himachal Pradesh, India during the kharif seasons of 2003-04 to evaluate the genetic parameters for quality traits in rice cultivars HPR 1164, HPR 2047, China 988, VL 91-1754, VL-93 3613, VL 93-6052, IR 57893-08, VL Dhan 221 and JD 8; their 36 hybrids (F1); and their 36 F2s. Variability was high for grain yield per plant. Additive gene action was found to be important for grain length, grain yield per plant and 100-grain weight, whereas both additive and non-additive gene actions were important for grain breadth, grain length:breadth ratio and protein content. Association analysis revealed that all the traits showed non-significant association with grain yield. Thus, it is evident from the present investigation that all the characters can be improved in a genotype without any adverse effect on grain yield per plant. Ali et al. (2007) evaluated twenty one CMS lines of rice from five different male sterility sources for various morphological, floral and agronomic traits at Rice Research Institute, Kala Shah Kaku, Pakistan. A considerable variation existed among CMS lines for these traits. Anther length and 16
stigma length ranged from 2.0 to 3.0 mm and 1.0 to 2.5 mm, respectively in these lines. This complete pollen sterility was observed in all CMS lines. On the basis of outcrossing ratio (OCR), better panicle exsertion ratio (PER) and stigma exsertion ratio (SER) and good phenotypic acceptability, CMS lines IR58025A, IR62829A, IR68897A, IR68886A, IR68896A, IR68885A (WA), IR69617A (Basmati type), IR66707A (Oryza perennis type) and 913A (Dian type) can be used for their exploitation in commercial hybrid rice seed production in Pakistan. Adil et al. (2007) studied the eight rice genotypes including six hybrids (HR-41, HR-30, HR-9, HR10, Arize-403, Dagha-1, KS 282 and Bas-385) in Pakistan to observe genetic variability among different plant traits contributing to yield. 2.2.2 Correlation co-efficient Ganesan (2000) conducted a study to assess the nature and magnitude of association between grain yield and its component characters of cytoplasmic male sterility, at Paddy Breeding Station, Tamil Nadu Agricultural University, Coimbatore using 48 hybrids derived from 6 lines and 8 testers. Most of the characters studied (days to flowering, plant height, number of tillers, productive tillers/plant, panicle exsertion, spikelets per panicle, filled grains per panicle and spikelet fertility) exhibited positive correlations with grain yield at both phenotypic as well as genotypic level. The results revealed that the direct selection for the above mentioned traits can improve the grain yield in CMS rice hybrids. Mahto et al. (2003) evaluated Twenty-six early maturing upland rice genotypes, collected from Jharkhand, India, for genetic variation, character association and path analysis based on days to 50% flowering, number of branches per panicle, number of filled grains per panicle, 1000-seed weight and grain yield. The association of high heritability with high genetic advance was observed for 1000-grain weight, days to 50% flowering, grain yield, number of branches per panicle. Grain yield 17
was positively and significantly correlated with days to 50% flowering, number of branches per panicle and number of filled grains per panicle. Path coefficient analysis showed that the number of branches per panicle (0.424) had the highest positive direct effect on grain yield followed by number of filled grains per panicle (0.411), and days to 50% flowering (0.07). Khedikar et al. (2003) estimated genetic variability for 9 characters (days to 50% flowering, plant height, effective tillers per plant, panicle length, test weight, sterility percentage, spikelet density, head rice recovery and grain yield per plant) in 20 scented rice genotypes. Analysis of variance showed sufficient variation among genotypes in all environments for the different yield and yield contributing characters studied. The phenotypic coefficient of variation (PCV) was higher than the genotypic coefficient of variation (GCV) for all characters, indicating that the variation among them is not only due to genetic content but also due to the influence of environment. Days to 50% flowering followed by plant height and head rice recovery recorded low GCV and PCV values in all environments. Borbora et al. (2005) conducted a field experiment with 30 rice genotypes and observed positive and significant correlation of grain yield per plant with grain yield per panicle and significant negative correlation with plant height, panicle number per plant and chaffy grain number per panicle. De et al. (2005) studied correlation and path analysis for 10 characters of 14 diverse aromatic cultivars and observed significant positive correlation on number of panicles per hill with grain yield per panicle. Sivakumar and KannanBapu (2005) assessed the nature and magnitude of association between grain yield and its component characters of wide compatible gene involving inter sub-specific rice hybrids. Most of the characters studied (number of tillers per plant, panicle length, pollen fertility, grains per panicle and 100-grain weight) had exhibited positive correlation with grain yield at both phenotypic 18
as well as genotypic levels. The results revealed that the direct selection for the above mentioned traits can improve the grain yield in wide compatible gene involving inter sub-specific rice hybrids. Patil and Sarawgi (2005) conducted an experiment on 128 aromatic rice accessions for genetic variation and correlation and found positive and significant correlation of grain with number of filled grains per panicle at genotypic and phenotypic level. Shashidhar et al. (2005) reported positive association of grain yield with plant height, number of productive tiller per hill, and dry matter per plant and harvest index at phenotypic and genotypic level. Vaithiyalingan and Nadarajan (2005) conducted an experiment to asses the nature and magnitude of association between grain yield and its components, and observed positive and significant relation of pollen fertility, plant height, and productive tillers per plant, panicle length, number of grains per panicle and spikelet fertility with grain yield. Satyanarayana et al. (2005) studied correlation and path co-efficient analysis for 66 restorer lines in rice and that yield was positively associated with spike let fertility, panicle length, number of grains per panicle and number of effective tillers per plant. Battan et al. (2006) studied 25 rice genotypes and observed high co-efficient of variation (GCV) and phenotypic co-efficient of variation (PCV) coupled with high heritability indicating further scope of improvement in this character grain yield per plant through selection. Zahid et al. (2006) studied 14 Basmati rice genotypes and found negative correlation of plant height with yield indicating that Bashmati plants had low yield.
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Singh et al. (2006) conducted an experiment with 37 rice genotypes to study character association reported that a grain yield having significant and positive association with number of grains per panicle followed by days to 50% flowering, effective tillers per plant and panicle length. Sankar et al. (2006) conducted an experiment with 34 rice genotypes and reported that single plant yield having positive and significant correlation with days to 50% flowering productive tillers per plant, panicle length and grains per panicle, and hence these traits can be taken as indices for improving yield in yield. 2.2.3 Path co-efficient study Yang-LianSong et al. (2002) grown Seeds of eight japonica rice varieties from different countries and seeds of F1 and F2 generations of their 56 hybrids (obtained by single cross and reciprocal cross) in Hefei, Anhui, China during 1999-2000. Rice grain shape traits (RGSTs) including grain length (GL), grain width (GW), grain thickness (GT) and grain weight were investigated after harvesting. No significant difference in GL was found among different hybrids, but their differences in GW, GT and grain weight reached a significant level. Significant difference in GL was noted between the hybrids obtained by single cross and reciprocal cross. It is inferred that the RGSTs were obviously controlled by female parent. Mahto et al. (2003) reported that the number of branches per panicle had the highest positive direct effect (0.424) on grain yield followed by number of filled grains per panicle (0.411), number of panicle per plant (0.159) and days to 50% flowering (0.07). Borbora et al. (2005) conducted an experiment with 16 local cultivars and 14 high yielding verities advance lines under two sowing dates and observed the highest positive direct effect of grain yield per panicle followed by plant height on grain yield per plant under both environments. Chaffy grain 20
number per panicle showed the highest negative direct effect on grain weight showed the highest indirect effects on grain yield per plant. Patil and Sarawgi (2005) worked out on path co-efficient in 128 aromatic rice accessions for seven traits and observed greatest positive direct effect of 1000-grain weight followed by number of earbearing tillers per plant, number of filled grains per panicle and number of days to 50% flowering on grain yield. However, 1000-grain weight had on significant correlation with grain yield per plant due to its negative indirect on grain yield plant through number of filled grain per panicle and plant height. Shashidhar et al. (2005) carried out an experiment on 20 double haploid lines of rice and yield components. Path analysis showed that dry matter per plant had the greatest positive direct effect on grin yield, followed by harvest index and plant height at the phenotypic level. Vaithiyalingan and Nadarajan (2005) conducted an experiment to assess the nature and magnitude of association between grain yield and its components, and observed positive and significant relation of pollen fertility, plant height, and productive tillers per plant, panicle length, number of grains per panicle and spikelet fertility with grain yield. Also studied correlation and path analysis in inter sub specific rice hybrids and reported that the number of grains per panicle had the highest positive direct effect on yield followed by productive tillers per plant. The results revealed that the direct selection for the above mentioned traits could improve the grain yield in interracial rice hybrids. Satyanarayana et al. (2005) studied path co-efficient analysis for 66 restorer lines in rice and observed that panicle length and spike let fertility exerted maximum direct effect on grain yield. High indirect effects of the different yield component traits studied were also noticed through spike let fertility on grain yield, indicating the need for emphasis on spike let fertility during selections for yield improvement in restorer lines of rice. 21
Vaithiyalingan and Nadarajan (2005) studied correlation and path analysis in inter sub specific rice hybrids and reported that the number of grains per panicle had the highest positive direct effect on yield followed by productive tillers per plant. The results revealed that the direct selection for the above mentioned traits could improve the grain yield in interracial rice hybrids. Zahid et al. (2006) observed that the number of tillers per plant, grains per panicle and 100-grain weight contributed maximum direct effect on yield.
2.3 Genetic Diversity Sarawgi et al. (1998) noticed genetic divergence as measured by the D 2 technique for 18 grain quality traits in 132 rice genotypes (128 traditional cultivars and 4 standard genotypes). The analysis of variance revealed significant differences among the genotypes for each character. The genotypes were grouped into 10 clusters and the maximum intra-cluster distance was observed in cluster VIII comprising of a single traditional rice cultivar Gonda Jhul. Clusters VI and VIII were identified as genetically divergent. Considering the cluster means and cluster distances, Bakal-B and Jondhera Dhan of cluster VI, Gonda Jhul of cluster VIII, Poorva and IR-36 of cluster VII, Kranchi, X-12, Moti Bakiya and Assam Chudi of cluster V and Kranti of cluster X were the most promising varieties. Jha et al. (1999) studied 20 accessions of wild rice species of Uttar Pradesh, India, were subjected to multivariate analysis following Mahalanobis's D2 statistics for assessing genetic diversity among them. The 20 accessions could be grouped into three clusters, exclusively of variants of specific species, without any overlap. Cluster 1 represented Oryza nivara with fourteen accessions, while cluster, II comprised of five accessions of O. sativa var, spontanea and cluster III with only accessions of O. rufipogon.
22
Soni et al. (1999) reported the genetic divergence of 132 rice genotypes (128 traditional cultivars and 4 standard genotypes) for 18 quality traits led to their grouping into 10 clusters. Grouping of genotypes in different clusters indicated the existence of significant amount of variability among the genotypes for the quality traits studies. Higher order of divergence was recorded between clusters VI and VII. Based on mean performance, genetic distance and clustering pattern, hybridization selected 10 genotypes are likely to give desirable segregants for grain quality. Bansal et al (1999) assessed genetic diversity in 34 rice stocks using D2 analysis of 10 economic traits. Thirty- four genotypes from seven countries were grouped into 15 clusters. The pattern of distribution of genotypes within various clusters was independent of geographical distribution. Based on mean performance, genetic distance and clustering pattern, intervarietal crosses were identified which might be useful in creating wider variability for early maturity, dwarf and high yielding segregants. Hegde and Patil (2000) reported the genetic divergence in 40 genotypes of rainfed rice using Mahalanobis's D2 statistic. The cultivars fall into 7 clusters. Cluster 1, II, III and IV comprised 18, 14, 3 and 2 genotypes, respectively, while Cluster V, VI and VII were solitary clusters. The average intercluster D2 value was the highest (51.88) between the Clusters V and VII, indicating high genetic divergence between the cultivars of these two clusters. The highest contributing characters to D 2 values were spikelet number per panicle, photosynthetic rate and 1000-grain weight. Based on genetic distance, mean performance and clustering pattern, hybridization of Panlcaj with CTH-3 or Kanthimori or Chachakki biliakki and CTH-3 with Kanthimori or Jolagabatta or Dodabatta was suggested to be appropriate in breeding. Rather et al. (2001) studied the genetic divergence in 56 rice cultivars in Jammu and Kashmir, India during the rainy season of 1997 and 1998. Significant variations for days to 50% flowering; leaf 23
length; leaf breadth; productive tillers per plant; plant height; days to maturity; total and sterile grains per panicle; panicle length, harvest index; grain yield; length; breadth ratio of the grain, and IQOgrain weight were observed among cultivars. The grouping of cultivars from various regions into the same cluster (as apparent in clusters I, II and VI) indicated that the geographical distribution did not necessarily indicate genetic divergence. The highest mean value for harvest index and the lowest spikelet sterility were observed for K 332. Based on the mean performance for plant height, maturity, spikelet fertility, grain yield and intercluster distance, cultivars from clusters II and IV may be used for initiating hybridization. Sharma et al. (2002) assessed genetic diversity in 28 yield and morphological traits of 100 aromatic rice genotypes, grown using Mahalanobis's D2 statistics. These genotypes, originating from different countries, were divided into 9 clusters. The pattern of distribution of genotypes within various clusters was random and independent of geographical isolation. Based on mean performance, genetic distance and clustering pattern, inter-crossing of genotypes Gam Poon, Khao Jao Hawam, Basmati Sufaid 187, KCN 80152, Abor Bora and Hara might be useful in creating wider variability for important agronomic and quality traits with high yielding segregants. Mishra et al. (2003) were determined the nature and magnitude of the genetic diversity for 20 quantitative and qualitative characters for 16 rice cultivars and their 72 F 1 hybrids during 1996-97 in Raipur, Madhya Pradesh, India. The genotypes were grouped in 12 clusters based on the relative magnitude of multivariate D2 values. The highest number of genotypes was in cluster XII. Based on the cluster means, plant height, flag leaf width, ear bearing tillers per plant, 100-seed weight, hulling and milling percentage, panicle length, biological yield, harvest index, kernel length after cooking, gelatinization temperature and grain yield were the main factors for differentiation. The highest genetic distance was observed between clusters III and VIII and lowest between cluster VII and VIII. No close correspondence was evidenced between geographical distribution to genetic divergence as 24
estimated by multivariate D2. Analysis of variance indicated highly significant differences for the most of the characters studied. Awasthi et al. (2005) conducted a field experiment to determine the genetic divergence of 21 Indian aromatic rice genotypes. A total of 21 aromatic rice genotypes were grouped into 6 clusters for different characters. The genotypes of one cluster indicated overall genetic similarity among them. The intercluster distance ranged from 0.00 for clusters IV, V and VI to 40.21 for cluster III. The intercluster distance was observed to be highest between clusters II and III, indicating that the genotypes of these two clusters were genetically more diverse. The number of grains per panicle, grain yield per plant, days to 50% flowering, leaf length and leaf width showed high percent contribution towards total genetic divergence. Bhutia et al. (2005) was carried out assessment of genetic divergence using Mahalanobis D 2 statistics on 41 high yielding and local genotypes of rice (Oryza sativa). The genotypes were grouped into six clusters. Cluster I had the highest number of genotypes (27) followed by cluster II with eight, and cluster III with three genotypes, respectively. Clusters IV, V and VI were monogenotypic. Cluster IV showed the maximum genetic distance from cluster VI followed by its distance from cluster V. The desirable yield and quality characteristics were distributed mainly in clusters III and IV and cluster V showed the highest value for protein. The genotypes included in clusters III and IV may be used as parents in hybridization programme to improve yield and cooking quality, whereas the genotypes in clusters III and V may be used in hybridization programmes to improve yield and nutritional quality with respect to protein. Deepak et al. (2006) conducted a genetic divergence study to estimate the nature and magnitude of diversity in 50 aromatic rice accessions including five scented improved varieties (Pusa Basmati, Taraori Basmati, Indira 9, Dubraj and Madhuri 11 as controls). The D 2 analysis indicated the 25
presence of appreciable amount of genetic diversity in the material. The 50 genotypes were grouped into 7 clusters. The cluster VI had the highest mean for grain yield per plant and for biological yield per plant. Intercluster distance was recorded highest between cluster III and cluster IV. The least distance was recorded in between cluster I and cluster V. The conclusion drawn by the cluster analysis was that high variability observed between the genotypes in different clusters for different characters in the studied population. Multivariate analysis was carried out with 30 advanced deep water lines of BRRI and 10 local rice germplasms collected from south-west of Bangladesh by Habib et al. (2007). The genotypes were grouped into six clusters. More emphasis should be given on cluster VI for selecting genotypes as parents for crossing with the genotypes for cluster II and III which may produce new recombinants with desired traits. Khalequzzaman et al. (2008) studied genetic diversity of 40 traditional Bangladeshi rice genotypes under rainfed condition through Mahalanobis D2 statistic for grain yield and yield contributing characters. The genotypes were grouped into six clusters. The inter cluster distances were higher than the intra cluster distances indicating wider genetic diversity among the genotypes of different clusters. The intra cluster distances were lower in all the cases reflecting homogeneity of the genotypes within the clusters. More emphasis should be given on cluster V and III for selecting genotypes as parents for crossing with the genotypes of cluster IV which would be used to produce new recombinants with desired traits.
26
CHAPTER III MATERIALS AND METHODS Experimental site The experiment was carried out at the experimental farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur during December 2008 to May 2009. The experimental site is located at the centre of Madhupur Tract (24º29 N latitude and 90º26 E longitude) having an elevation of 8.2m from the sea level (Anonymous, 1989). Soil and climate of the experimental site The soil type of experimental field belongs to the Shallow Red Brown Terrace type under Salna Series of Madhupur Tract (Brammer, 1971) of Agro Ecological Zone (AEZ) 28 which is characterized by silty clay with pH value of 6.5. The climate of the experimental site is subtropical to nature. The air temperature, humidity and rainfall during the period of experiment were noted from the meteorological station of BSMRAU, Gazipur (Appendix- II). Design and layout The experimental plots were laid out in randomized complete block design (RCBD). The field was divided into three blocks, the blocks were subdivided into 52 plots where genotypes were randomly assigned. The unit plot size was 12.5m x 2.5m. Each plot had two lines. Row to row and plant to plant distances were 25cm and 20cm respectively. The genotypes were distributed to each plot within each block randomly.
27
Materials The experiment was conducted using 50 genotypes of exotic rice with 2 check variety is given below: Germination of seed SI. #
Acc# No.
Sources
SI. #
Acc# No.
Sources
1
RG-BU-08-051
GPB, BSMRAU
27
RG-BU-08-077
GPB, BSMRAU
2
RG-BU-08-052
GPB, BSMRAU
28
RG-BU-08-078
GPB, BSMRAU
3
RG-BU-08-053
GPB, BSMRAU
29
RG-BU-08-079
GPB, BSMRAU
4
RG-BU-08-054
GPB, BSMRAU
30
RG-BU-08-080
GPB, BSMRAU
5
RG-BU-08-055
GPB, BSMRAU
31
RG-BU-08-081
GPB, BSMRAU
6
RG-BU-08-056
GPB, BSMRAU
32
RG-BU-08-082
GPB, BSMRAU
7
RG-BU-08-057
GPB, BSMRAU
33
RG-BU-08-083
GPB, BSMRAU
8
RG-BU-08-058
GPB, BSMRAU
34
RG-BU-08-084
GPB, BSMRAU
9
RG-BU-08-059
GPB, BSMRAU
35
RG-BU-08-085
GPB, BSMRAU
10
RG-BU-08-060
GPB, BSMRAU
36
RG-BU-08-086
GPB, BSMRAU
11
RG-BU-08-061
GPB, BSMRAU
37
RG-BU-08-087
GPB, BSMRAU
12
RG-BU-08-062
GPB, BSMRAU
38
RG-BU-08-088
GPB, BSMRAU
13
RG-BU-08-063
GPB, BSMRAU
39
RG-BU-08-089
GPB, BSMRAU
14
RG-BU-08-064
GPB, BSMRAU
40
RG-BU-08-090
GPB, BSMRAU
15
RG-BU-08-065
GPB, BSMRAU
41
RG-BU-08-091
GPB, BSMRAU
16
RG-BU-08-066
GPB, BSMRAU
42
RG-BU-08-092
GPB, BSMRAU
17
RG-BU-08-067
GPB, BSMRAU
43
RG-BU-08-093
GPB, BSMRAU
18
RG-BU-08-068
GPB, BSMRAU
44
RG-BU-08-094
GPB, BSMRAU
28
19
RG-BU-08-069
GPB, BSMRAU
45
RG-BU-08-095
GPB, BSMRAU
20
RG-BU-08-070
GPB, BSMRAU
46
RG-BU-08-096
GPB, BSMRAU
21
RG-BU-08-071
GPB, BSMRAU
47
RG-BU-08-097
GPB, BSMRAU
22
RG-BU-08-072
GPB, BSMRAU
48
RG-BU-08-098
GPB, BSMRAU
23
RG-BU-08-073
GPB, BSMRAU
49
RG-BU-08-099
GPB, BSMRAU
24
RG-B U-08-074
GPB, BSMRAU
50
RG-BU-08-100
GPB, BSMRAU
RG-BU-08-075
GPB, BSMRAU
51
Check Variety-I
GPB, BSMRAU
25
(BRRI dhan 28) 26
RG-BU-08-076
GPB, BSMRAU
52
Check Variety-II
GPB, BSMRAU
(BRRI dhan29) Seeds of all collected rice genotypes soaked separately for 48 hours in clothes bag. Soaked seeds were picked out from water and wrapped with straw and gunny bag to increase the temperature for facilitating germination. Preparation of seedbed and raising seedling The irrigated land was prepared thoroughly by 3-4 times ploughing and cross ploughing followed by laddering to attain a good puddle. Weeds and stubbles were removed. Fifteen separate strips were made and sprouted seeds were sown on each strip @100g seed per square meter. Seedbed was irrigated with regular interval to maintain moisture. Preparation of main land The experimental plot was at a lower elevation with high water holding capacity. The land was prepared thoroughly by 3-4 times ploughing and cross ploughing followed by laddering to attain a good puddle. Weeds and stubbles were removed and land was finally prepared by the addition of basal dose of fertilizers recommended by BSMRAU (Anonymous, 1999).
29
Application of fertilizers The experimental plot was fertilized by applying urea, TSP, MP and Gypsum @180-100-70-60 Kg/ha, respectively. Total TSP, MP and Gypsum were applied at final land preparation. Total urea was applied in three installments, at 15 days after transplanting (DAT), 30 DAT and 50 DAT recommended by BSMRAU (Anonymous, 1999). Intercultural operation Necessary intercultural operations were made during cropping period for proper growth and development of the plants. Irrigation with regular interval was given to maintain 5-7 cm water up to hard drought stage of rice. Plant protection measures For proper control measures against rice stem borer, furadan 5G @1g per square meter were applied at active tillering stage and panicle initiation stage of rice. Collection of data Data were collected from 5 hills of each genotype on individual plant basis A.
B.
Morphological characters (on the basis of morphological descriptors)
o
Panicle color
o
Awning
o
Panicle type
o
Seed shape
o
Seed coat color
o
Seed length and seed breadth
Agronomic characters
30
Days to first flowering (DFF) Number of days required for production of panicles from the boot leaf in 5% of the plants. Days to initial flowering was recorded from the date of transplanting of seedlings to date of 5% flowering. Days to 50% flowering (50%DF) Number of days required for 50% of panicles emergence in most of plants of a line. Days to 50% flowering was recorded from the date of transplanting of seedlings to date of 50% flowering. Days to harvesting (DH) Days to harvesting was recorded from the date of transplanting of seedlings to date of harvesting of panicles. Anther length (µ) [AL] The length was recorded by ocular micrometer under compound microscope. After that it was calibrated by stage micrometer to convert it into micron (µ). Anther breadth (µ) [AB] The breadth was recorded by ocular micrometer under compound microscope. After that it was calibrated by stage micrometer to convert it into micron (µ). Stigma length (µ) [SL] The length was recorded by ocular micrometer under compound microscope from base to the tip of the stigma and then it was calibrated by stage micrometer to convert the length into micron (µ). Stigma breadth (µ) [SB] The breadth was recorded by ocular micrometer under compound microscope. After that it was calibrated by stage micrometer to convert it into micron (µ).
31
Pollen sterility (%) [PS] Pollen sterility was measured by crushing the anther on a slide containing 1% iodine potassium iodide solution (1% IKI) and then counted the sterile and viable pollen under compound microscope. Percent pollen sterility was recorded by following formula:
% Pollen Sterility =
Number of sterile pollen under microscopic field × 100 Total number of pollen under microscopic field
Pollen fertility (%) [PF] Pollen fertility was measured by crushing the anther on a slide containing 1% iodine potassium iodide solution (1% IKI) and then counted the fertile and sterile pollen under compound microscope. Percent pollen fertility was recorded by following formula:
% Pollen Fertility =
Number of fertile pollen under microscopic field × 100 Total number of pollen under microscopic field
The pollen grains were classified based on their shape, size and extent of staining. Classification of pollen based on shape and staining Category
Classification
Unstained withered pollen (UWS)
Sterile
Unstained spherical pollen (USS)
Sterile
Lightly stained round pollen (SRS)
Sterile
Stained round pollen (SRF)
Fertile
32
Classification of pollen based on extent of Pollen Sterility and Pollen Fertility Pollen Sterility (%)
Pollen Fertility (%)
Category
100
0
Completely sterile (CS)
91-99
1-9
Sterile (S)
71-90
10-29
Partially sterile (PS)
31-70
30-69
Partially fertile (PF)
21-30
70-79
Fertile (F)
0-20
80-100
Fully fertile (FF)
Spikelet sterility (%) [SS] Number of sterile spikelets of 5 panicles was recorded and sterility percentage was calculated by the following formula:
% Spikelet sterility =
Number of sterile spikelets of 5 panicles × 100 Number of total spikelets of 5 panicles
Out crossing rate (%) [OCR] Out crossing rate (%) refers to the extent of seed set on open pollinated panicles, expressed in percentage. It was computed according to the following formula:
Out crossing rate (%) =
No. of filled spikelets × 100 Total no. of spikelets
Filled grains per panicle (FGP) Total number of filled grains of the main panicle of each sample plant was counted and average was taken.
33
Unfilled grains per panicle (UGP) Total number of unfilled grains of the main panicle of each sample plant was counted and average was taken. Grain length (mm) [GL] The grain length was recorded by slide calipers in mm. Grain breadth (mm) [GB] The grain breadth was recorded by slide calipers in mm. Grain yield per hill (g) [GYH] All the seeds of five hills were dried in the sun (drying continued until reaches 14% moisture content), weighed in gram and measured by dividing it by five.
Analysis of data: Estimation of genotypic and phenotypic variance Genotypic and Phenotypic Variances were estimated according to the formula given by Johnson et al., (1955).
Genotypic variance (σ2g) =
GMS - EMS r
Where, GMS = Genotypic mean square
Phenotypic Variance (σ2p) = σ2g + EMS Where,
EMS = Error mean square R = Number of replication σ2g = Genotypic variance
34
Estimation of Genotypic and Phenotypic Co-efficient of Variation Genotypic and Phenotypic co-efficient of variation were estimated according to Burton (1952) and Singh and Chaudhary (1985). Genotypic co-efficient of variation,
(GCV) =
2g x
2p x
σ2g = Genotypic variance
× 100
Phenotypic co-efficient of variation,
(PCV) =
Where,
Where, σ2p = Phenotypic variance
× 100
Estimation of heritability Heritability was estimated in broad sense by the formula suggested by Johnson et al., (1955).
2g Heritability (h b) = 2 × 100 p
Where,
2
σ2g = Genotypic variance
Estimation of genetic advance Estimation of Genetic Advance was done following formula given by Johnson et al., (1955). Where, Genetic Advance (GA) = h2b.K.σp
h2b = Heritability K = Selection differential, the value of which is 2.06 at 5% selection intensity; and
35
Estimation of correlation coefficients The Genotypic and Phenotypic correlation coefficients between yield and different yield contributing characters were estimated as:
Where,
Genotypic correlation =
Cov(g)(xy) = Genotypic covariance
Cov(g)1.2
between the variables X and Y
2 ( g )1. 2 ( g )2
σ2(g)1 = Genotypic variance of the variable X1 σ2(g)2 = Genotypic variance of the Where,
Similarly,
Cov(ph)(xy) = Phenotypic correlation =
Cov(ph)1.2
covariance
between the variables X and Y
( ph)1. ( ph)2 2
Phenotypic
2
σ2(ph)1 = Phenotypic variance of the variable X1 σ2(ph)2 = Phenotypic variance of the
Estimation of path coefficients Path coefficient analysis was done according to the procedure employed by Dewey and Lu (1959) also quoted in Singh and Chaudhary (1985), using phenotypic correlation coefficient values. In path analysis, correlation coefficients between yield and yield contributing characters were partitioned into direct and indirect effects of yield contributing characters on grain yield per hectare. After calculating the direct and indirect effect of the characters, residual effects (R) was calculated by using the formula given below (Singh and Chaudhary, 1985).
36
P2RY = 1- (r1.y P1.y + r2.y P2.y + …………………….+ r12.y P12.y) PI.y = Direct effect of the i th character on Where,
yield y. P2RY = R2 and hence residual effect, R = (P2RY)1/2
rI.y = Correlation of the i th character with yield y.
Genetic diversity Genetic diversity was analyzed using GENSTAT 5.13 software program (copyright 1987, Lawes Agricultural Trust, Rothamasted Experimental Station, UK). Genetic diversity analysis involves several steps, i.e., estimation of distance between the varieties clustering and analysis of inter-cluster distance. Therefore, more than one multivariate techniques are required to represent the results more clearly and it is obvious from the results of many researchers (Bashar, 2002, Uddin, 2001, Juned et al., 1988, Ariyo, 1987, Patil et al., 1987, Dani and Murthy, 1985, Anand and Rawat, 1984 and Balasch et al., 1984). Principal component analysis (PCA) Analysis of genetic diversity in rice following multivariate techniques was used and mean data for each character were subjected to use. Principal components were computed from the correlation matrix and genotype scores obtained from first components (which has the property accounting for maximum variance) and succeeding components with latent roots greater than the unity (Jeger et al., 1983) and contribution of the different morphological characters towards divergence are discussed from the latent vectors of the first two principal components. To divide the varieties of a data set into some number of mutually exclusive groups clustering was done using non-hierarchical classification. The algorithm is used to search for optimum values of chosen criterion. Starting from some initial classification of the varieties into required number of groups, the algorithm repeatedly transfers varieties from one group to another so long as such transfer improve the value of the criterion the algorithm switches to a second stage which examines the effect of swapping two varieties of different classes and so on.
37
Principal coordinate analysis (PCO) Principal coordinate analysis is equivalent to PCA but it is used to calculate inter unit distances. Through the use of all dimension of P it gives the minimum distance between each pair of the N point using similarly matrix (Digby et al., 1989). Canonical vector analysis (CVA) Canonical vector analysis (CVA) complementary to D2 statistic is a sort of multivariate analysis where canonical vector and roots representing different axes of differentiation and the amount of variation accounted for by each of such axes, respectively and derived. Canonical vector analysis finds linear combination of original variability than maximize the ratio of between groups to within group’s variation, thereby giving functions of the original variables that can be used to discriminate between the groups. Thus in this analysis a series of orthogonal transformation sequentially maximize the ratio of among groups to within group variation. Computation of average intra-cluster distances The average intra cluster distance for each cluster was calculated by taking all possible D2 values within the members of a cluster obtained from PCO. The formula used to measure the average intra-cluster distance was as follows: Intra-cluster distance = ∑D2/n Where, D2 is the sum of distances between all possible combinations (n) of the genotypes included in a cluster. The square root of the D2 values represents the distance (D) within cluster.
38
CHAPTER IV RESULTS AND DISCUSSION This chapter comprises the presentation and discussion of the findings obtained from the study. A. Characterization of different exotic rice genotypes A.1. Various characteristics of different exotic rice genotypes The genotype RG-BU-08-072 showed dark red panicle in colour (Table 1; Fig. 1). The genotypes RG-BU-08-076, 80, 82 and 99 showed light red panicle in colour and others showed greenish in colour. The genotypes RG-BU-08-072, 76, 78, 79, 82, 91 and 99 showed closed panicle type. The genotypes RG-BU-08-052, 54, 58, 62, 65, 66, 68, 69, 70, 73, 74, 75, 80, 84, 90, 92, 95 and 97 showed intermediate panicle type and remaining genotypes had open type panicle. The genotypes RG-BU08-056, 58, 64 and 100 showed short and fully awned grain (Table 1; Fig. 2). The genotypes RGBU-08-065 and 68 showed short and partly awned grain. The genotypes RG-BU-08-073 had long and fully awned grain. Other genotypes awnless. The genotype RG-BU-08-096 showed very small and round grain, whereas 99 showed very large and long grain. Elongate type grain found in genotypes RG-BU-08-077, 83, 89 and 98 as well as medium grain found in genotypes RG-BU-08055, 57, 61, 64, 65, 67, 85 and 86 (Table 1; Fig. 2).
39
Table 1: Various specialties of different exotic rice genotypes Genotype
Panicle color
Panicle type
Awning
Seed shape
Seed length Seed breadth (mm) (mm)
Seed coat color
RG-BU-08-051
Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Dark red Greenish Greenish Greenish Light red Greenish
Open Intermediate Open Intermediate Open Open Open Intermediate Compact Open Open Intermediate Open Open Intermediate Intermediate Open Intermediate Intermediate Intermediate Open Closed Intermediate Intermediate Intermediate Closed Open
Absent Absent Absent Absent Absent Short and fully awned Absent Short and fully awned Absent Absent Absent Absent Absent Short and fully awned Short and partly awned Absent Absent Short and partly awned Absent Absent Absent Absent Long and fully awned Absent Absent Absent Absent
Medium, Long Small, Round Small, Round Small, Long Medium Medium, Long Medium Medium, Long Small, Round Medium, Long Medium Medium, Long Elongate, Long Medium Medium Medium, Long Medium Medium, Round Small, Round Small, Round Medium, Round Medium, Round Medium, Long Medium, Round Medium, Long Small, Round Elongate
9.93 8.87 8.32 8.61 9.79 10.38 9.04 9.47 7.54 9.93 8.06 7.71 10.03 10.23 9.18 9.54 9.08 9.49 8.60 8.32 9.06 9.33 9.46 9.99 9.31 7.04 9.61
Brown Golden Light brown Golden Light brown Light brown Brown Golden Light brown Brown Light brown Golden Light brown Brown Golden Brown Golden Light brown Brown Variable purple Golden Light brown Brown Brown Golden Golden Brown
RG-BU-08-052 RG-BU-08-053 RG-BU-08-054 RG-BU-08-055 RG-BU-08-056 RG-BU-08-057 RG-BU-08-058 RG-BU-08-059 RG-BU-08-060 RG-BU-08-061 RG-BU-08-062 RG-BU-08-063 RG-BU-08-064 RG-BU-08-065 RG-BU-08-066 RG-BU-08-067 RG-BU-08-068 RG-BU-08-069 RG-BU-08-070 RG-BU-08-071 RG-BU-08-072 RG-BU-08-073 RG-BU-08-074 RG-BU-08-075 RG-BU-08-076 RG-BU-08-077
40
3.19 3.33 3.14 3.14 3.09 2.68 2.71 2.39 3.20 2.31 2.63 2.41 2.77 2.83 2.39 3.04 2.83 2.95 3.07 3.75 2.82 3.12 2.42 3.07 2.82 3.35 2.45
Table 1. Contd... Genotype RG-BU-08-078 RG-BU-08-079 RG-BU-08-080 RG-BU-08-081 RG-BU-08-082 RG-BU-08-083 RG-BU-08-084 RG-BU-08-085 RG-BU-08-086 RG-BU-08-087 RG-BU-08-088 RG-BU-08-089 RG-BU-08-090 RG-BU-08-091 RG-BU-08-092 RG-BU-08-093 RG-BU-08-094 RG-BU-08-095 RG-BU-08-096 RG-BU-08-097 RG-BU-08-098 RG-BU-08-099 RG-BU-08-100 BRRI dhan28 BRRI dhan29
Panicle color Greenish Greenish Light red Greenish Light red Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Greenish Light red Greenish Greenish Greenish
Panicle type
Awning
Seed shape
Seed Length Seed breadth (mm) (mm)
Seed Coat color
Closed
Absent
7.44
Closed
Absent Absent
Small, Round Small, Round Small, Round
Light brown Light brown Golden Brown
Intermediate Open Closed
Open Intermediate Open Open Open Open Open Intermediate
Closed Intermediate Open Open Intermediate Closed Intermediate
Open Closed Open Intermediate Intermediate
7.84 8.07 Absent Medium, Long 9.45 Absent Small, Round 7.35 Absent Elongate 9.04 Absent Medium, Long 10.43 Absent Medium 9.18 Absent Medium 8.47 Small, Round Absent 9.71 Small, Round Absent 9.75 Absent Elongate 10.31 Absent Medium, Long 9.91 Medium, Long Absent 9.30 Small, Medium Absent 10.25 Small, Round Absent 9.96 Absent Medium, Long 9.82 Absent Medium, Long 9.63 Absent Very small, Round 6.27 Absent Medium, Long 9.60 Absent Elongate 9.51 Absent Very large, Long 14.05 Short and fully awned Medium, Round 8.36 Absent Medium 9.25 Absent Medium 8.60 41
3.52
3.63 3.32 2.95 2.81 2.51 2.92 3.26 2.46 2.02 3.65 2.53 2.42 2.76 2.73 2.79 2.86 2.78 2.81 3.07 2.45 4.33 3.05 2.51 2.60
Light brown Light brown
Purple Brown Brown Light brown Brown Golden Brown Light brown Light brown
Brown Golden Light brown
Variable purple Brown Brown Variable purple Variable purple Light brown Light brown
Figure 1: Various panicle colors in exotic rice genotypes
RG-BU-08-051 RG-BU-08-052 RG-BU-08-053 RG-BU-08-054
RG-BU-08-055 RG-BU-08-056 RG-BU-08-057
RG-BU-08-058 RG-BU-08-059 RG-BU-08-060 RG-BU-08-061 RG-BU-08-062
RG-BU-08-063 RG-BU-08-064
RG-BU-08-065 RG-BU-08-066 RG-BU-08-067 RG-BU-08-068 RG-BU-08-069 RG-BU-08-070 RG-BU-08-071
RG-BU-08-072 RG-BU-08-073 RG-BU-08-074 RG-BU-08-075
43
RG-BU-08-076 RG-BU-08-077 RG-BU-08-078
Figure 1: Various panicle colors in exotic rice genotypes
RG-BU-08-079 RG-BU-08-080 RG-BU-08-081 RG-BU-08-082 RG-BU-08-083 RG-BU-08-084 RG-BU-08-085
RG-BU-08-086 RG-BU-08-087 RG-BU-08-088 RG-BU-08-089 RG-BU-08-090 RG-BU-08-091 RG-BU-08-092
RG-BU-08-093 RG-BU-08-094 RG-BU-08-095 RG-BU-08-096 RG-BU-08-097 RG-BU-08-098
RG-BU-08-100 BRRI dhan 28 BRRI dhan 29
44
RG-BU-08-099
Figure 2: Figure shows various panicle type in exotic rice genotypes
RG-BU-08-051 RG-BU-08-052 RG-BU-08-053 RG-BU-08-054 RG-BU-08-055 RG-BU-08-056 RG-BU-08-057 RG-BU-08-058
RG-BU-08-059 RG-BU-08-060 RG-BU-08-061 RG-BU-08-062 RG-BU-08-063 RG-BU-08-064 RG-BU-08-065 RG-BU-08-066
RG-BU-08-067 RG-BU-08-068 RG-BU-08-069 RG-BU-08-070 RG-BU-08-071 RG-BU-08-072
RG-BU-08-073 RG-BU-08-074
RG-BU-08-075 RG-BU-08-076 RG-BU-08-077 RG-BU-08-078 RG-BU-08-079 RG-BU-08-080
RG-BU-08-081 RG-BU-08-082
RG-BU-08-083 RG-BU-08-084 RG-BU-08-085 RG-BU-08-086 RG-BU-08-087 RG-BU-08-088 RG-BU-08-089 RG-BU-08-090
RG-BU-08-091 RG-BU-08-092 RG-BU-08-093 RG-BU-08-094 RG-BU-08-095 RG-BU-08-096 RG-BU-08-097 RG-BU-08-098
RG-BU-08-099 RG-BU-08-100 BRRI dhan 28 BRRI dhan 29
45
Figure 3: Figure shows various seed shape and seed colour in exotic rice genotypes
RG-BU-08-051
RG-BU-08-052
RG-BU-08-053
RG-BU-08-058
RG-BU-08-059
RG-BU-08-060
RG-BU-08-061
RG-BU-08-065
RG-BU-08-066
RG-BU-08-067
RG-BU-08-072
RG-BU-08-073
RG-BU-08-079
RG-BU-08-086
RG-BU-08-093
RG-BU-08-056
RG-BU-08-057
RG-BU-08-062
RG-BU-08-063
RG-BU-08-064
RG-BU-08-068
RG-BU-08-069
RG-BU-08-070
RG-BU-08-071
RG-BU-08-074
RG-BU-08-075
RG-BU-08-076
RG-BU-08-077
RG-BU-08-078
RG-BU-08-080
RG-BU-08-081
RG-BU-08-082
RG-BU-08-083
RG-BU-08-084
RG-BU-08-085
RG-BU-08-087
RG-BU-08-088
RG-BU-08-089
RG-BU-08-090
RG-BU-08-091
RG-BU-08-092
RG-BU-08-094
RG-BU-08-095
RG-BU-08-095
RG-BU-08-054
RG-BU-08-055
RG-BU-08-096
BRRI dhan 28
46
RG-BU-08-097
BRRI dhan 29
RG-BU-08-098
RG-BU-08-099
The genotypes RG-BU-08-84 showed purple seed coat color whereas genotypes RG-BU-08-070, 96, 99 and 100 gave variable purple seed coat color. The genotypes RG-BU-08-51, 57, 60, 66, 69, 73, 74, 77, 81, 85, 86, 88, 90, 93, 97 and 98 showed brown seed coat color. The genotypes RGBU-08-55, 54, 58, 62, 65, 67, 71, 75, 76, 80, 89 and 94 showed golden seed coat colour whereas others showed light brown seed coat color. The genotype RG-BU-08-099 showed highest seed length (14.05 mm) which was followed by the genotypes RG-BU-08-084, 56 and 89. The genotype RG-BU-08-096 took the lowest seed length (6.27 mm) which was followed by the genotypes RG-BU-08-076, 82 and 78. The genotype RG-BU-08-099 showed highest seed breadth (4.33 mm) which was followed by the genotypes RG-BU-08-070, 88 and 79. The genotype RGBU-08-087 took the lowest seed breadth (2.02 mm) which was followed by the genotypes RGBU-08-060, 65 and 58 (Table 1). A.2. Searching against pollen sterility source Regarding pollen sterility, one seven genotypes were sterile (S) [genotypes RG-BU-08-057, 65, 66, 67, 71, 85 and 86], four genotypes were partially sterile (PS) [genotypes RG-BU-08-055, 76, 81 and 84], nine genotypes were partially fertile (PF) [genotypes RG-BU-08-068, 74, 75, 79, 80, 82, 93, 95 and 99], six genotypes were fertile (F) [genotypes RG-BU-08-070, 73, 78, 87, 96 and 97] as well as twenty four genotypes were fully fertile (FF) genotypes [RG-BU-08-051, 52, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 69, 72, 77, 83, 88, 89, 90, 91, 92, 94, 98 and 100] (Table 2). In case of pollen fertility, nine genotypes were partially fertile (PF) [genotypes RG-BU-08-052, 68, 74, 75, 79, 80, 82, 93 and 99], five genotypes were fertile (F) [genotypes RG-BU-08-070, 73, 87, 96 and 97] and others twenty four genotypes were fully fertile (FF) [genotypes RG-BU-08-051, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 69, 72, 77, 78, 83, 88, 89, 90, 91, 92, 94, 98 and 100] (Table 2).
47
Table 2: Pollen sterility and spikelet sterility status of different exotic rice genotypes
Accession No. Pollen sterility
Status
Pollen fertility Status
(%)
(%)
Spikelet sterility
Status
(%)
RG-BU-08-051
14.89
FF
85.11
FF
21.167
F
RG-BU-08-052
5.56
FF
94.44
PF
9.540
FF
RG-BU-08-053
2.00
FF
98
FF
41.157
PF
RG-BU-08-054
6.89
FF
93.11
FF
29.877
F
RG-BU-08-055
79.11
PS
18.67
PS
34.627
PF
RG-BU-08-056
0.33
FF
99.67
FF
20.653
F
RG-BU-08-057
98.33
S
1.67
S
23.733
F
RG-BU-08-058
10.22
FF
89.78
FF
34.600
PF
RG-BU-08-059
11.33
FF
88.67
FF
23.060
F
RG-BU-08-060
0.17
FF
99.83
FF
30.810
PF
RG-BU-08-061
19.33
FF
80.67
FF
47.427
PF
RG-BU-08-062
0.13
FF
99.87
FF
21.860
F
RG-BU-08-063
6.73
FF
93.27
FF
30.310
F
RG-BU-08-064
8.67
FF
91.33
FF
36.993
PF
RG-BU-08-065
98.22
S
1.78
S
25.867
F
RG-BU-08-066
95.04
S
4.96
S
35.103
PF
RG-BU-08-067
97.78
S
2.22
S
40.870
PF
RG-BU-08-068
51.89
PF
48.11
PF
29.180
F
RG-BU-08-069
0.13
FF
99.47
FF
40.480
PF
RG-BU-08-070
21.33
F
78.67
F
33.613
PF
RG-BU-08-071
98.16
S
1.84
S
23.753
F
RG-BU-08-072
9.33
FF
90.45
FF
28.183
F
RG-BU-08-073
25.78
F
74.22
F
22.873
F
RG-BU-08-074
68.89
PF
31.11
PF
32.075
PF
RG-BU-08-075
42.22
PF
57.78
PF
31.390
PF
RG-BU-08-076
86.00
PS
14.00
PS
12.740
FF
48
Table 2. Contd... Accession No.
Pollen Sterility
Status
Pollen Fertility
(%)
Status
(%)
Spikelet Sterility
Status
(%)
RG-BU-08-077
0.44
FF
99.22
FF
23.090
F
RG-BU-08-078
21.56
F
78.44
F
36.680
PF
RG-BU-08-079
67.55
PF
32.45
PF
6.547
FF
RG-BU-08-080
52.00
PF
48.00
PF
15.637
FF
RG-BU-08-081
84.22
PS
15.78
PS
20.310
F
RG-BU-08-082
62.44
PF
37.56
PF
25.763
F
RG-BU-08-083
5.00
FF
95.00
FF
13.697
FF
RG-BU-08-084
81.56
PS
19.55
PS
32.887
PF
RG-BU-08-085
99.87
S
0.13
S
24.677
F
RG-BU-08-086
98.79
S
1.21
S
25.110
F
RG-BU-08-087
21.78
F
78.22
F
25.997
F
RG-BU-08-088
15.11
FF
88.22
FF
42.673
PF
RG-BU-08-089
1.73
FF
98.27
FF
36.817
PF
RG-BU-08-090
11.11
FF
88.89
FF
20.997
F
RG-BU-08-091
3.78
FF
96.22
FF
29.327
F
RG-BU-08-092
18.89
FF
81.11
FF
28.387
F
RG-BU-08-093
66.22
PF
33.34
PF
20.257
F
RG-BU-08-094
2.78
FF
97.22
FF
10.677
FF
RG-BU-08-095
56.67
PF
43.33
PF
13.617
F
RG-BU-08-096
23.11
F
76.89
F
46.753
PF
RG-BU-08-097
27.78
F
72.22
F
36.583
PF
RG-BU-08-098
9.78
FF
89.11
FF
33.697
PF
RG-BU-08-099
55.78
PF
44.22
PF
53.047
PF
RG-BU-08-100
6.67
FF
93.33
FF
15.820
FF
BRRI dhan28
17.11
FF
82.89
FF
18.387
FF
BRRI dhan29
18.39
FF
92.22
FF
23.307
F
49
Pollen sterility status
Pollen fertility status
Completely sterile (CS):100%
Completely sterile (CS):0%
Sterile (S): 91-99%
Sterile (S): 1-9%
Partially sterile (PS): 71-90%
Partially sterile (PS): 10-29%
Partially fertile (PF): 31-70%
Partially fertile (PF): 30-69%
Fertile (F): 21-30%
Fertile (F): 70-79%
Fully fertile (FF): 0-20%
Fully fertile (FF): 80-100%
50
B. Variability for Agronomic Traits in Exotic Rice Germplasm The mean performances of different quantitative characters of individual genotypes with Duncan’s Multiple Range Test (DMRT) are presented in Appendix III, the corresponding analysis of variance and the variability of 50 exotic rice genotypes with 2 check varieties are presented in Table 3 and Table 4, respectively. B.1. Variation and performance of the genotypes The analysis of variance of different genotypes of rice for yield and reproductive characters are shown in Table 3. Analysis of variance for the characters showed highly significant variations among the tested genotypes. This indicated that there was a wide genotypic variation among the genotypes for all the characters. Days to first flowering Analysis of variance for days to first flowering was significant indicating existence of considerable difference among the genotypes for this trait (Table 3). The maximum days to first flowering was found 98 days and the minimum was recorded as 74 days with a mean value of 81.846 days (Table 4). While the genotype RG-BU-08-096 took the longest period for first flowering (98) followed by RG-BU-08-063, 91 and 97. The genotype RG-BU-08-066 took the minimum days to first flowering (74 days) followed by RG-BU-08-85. The rest of the genotypes were different in flowering time and were of medium to long duration in flowering (Appendix III). Similar results were also reported by Souroush et al. (2005).
51
Table 3: Analysis of variance for 16 characters of 50 of exotic rice genotypes with two check varieties Sources of df variation Replication Genotype Error
2
DFF
50% DF
10.635
13.058
DH 8.795
AL(µ)
AB(µ)
SL(µ)
SB(µ)
% PS
5.736
5.530
12.852
12.556
66.311
51 136.738** 97.776** 74.572** 693.586** 65.213** 316.990** 52.514** 3718.338** 102
CV%
5.818
3.927
1.279
28.929
11.789
28.768
5.406
125.606
2.95
2.17
0.97
5.58
15.04
9.22
10.47
3.83
** = Significant at 1% level,
* = Significant at 5% level, ns = Non-significant
Table 3. Contd…. Sources of df %PF variation
% SS
%OCR
90.06
15.130
14.857
Replication 2
FGP
UGP
297.011
3.218
GL (mm) 0.082
GB (mm) 0.032
GYH (g) 41.278
Genotype 51 3760.517** 309.177** 309.378** 2110.328**1195.884** 4.054** 0.542** 176.871** Error CV%
102 119.470 17.10
21.467
21.449
163.708
73.677
0.024
0.016
18.198
16.70
6.41
12.34
21.06
1.68
4.31
15.89
Legend: DFF = Days to first flowering, 50% DF = Days to 50% flowering, DH = Days to harvesting, AL = Anther length(µ), AB = Anther breadth(µ), SL = Stigma length(µ), SB = Stigma breadth(µ), PS = Pollen sterility%, PF = Pollen fertility%, SS = Spikelet sterility%, OCR = Out crossing rate%, FGP= Filled grains per panicle, UGP = Unfilled grains per panicle, GL = Grain length(mm), GB = Grain breadth(mm), GYH= Grain yield per hill (g).
51
Table 4: Varietal differences in 16 characters of 50 exotic rice genotypes with 2 check varieties
Character
Standard deviation
Standard error
Minimum
Maximum
Mean
DFF
74.000
98.000
81.846
6.751
0.922
50% D F
81.000
103.667
91.250
5.709
0.780
DH
111.000
124.000
116.776
4.986
0.681
AL
47.800
146.267
96.318
15.205
2.077
AB
14.333
36.200
22.827
4.662
0.637
SL
36.917
84.167
58.173
10.279
1.404
SB
13.417
32.917
22.202
4.184
0.572
PS
0.133
99.867
36.350
35.206
4.810
PF
0.133
99.867
63.930
35.405
4.837
SS
6.547
53.047
27.744
10.152
1.387
OCR
46.953
93.453
72.251
10.155
1.387
FGP
29.000
197.933
103.709
26.522
3.623
UGP
5.733
102.333
40.749
19.966
2.728
GL
6.267
14.053
9.182
1.163
0.159
GB
2.017
4.327
2.897
0.425
0.058
GYH
7.820
38.907
26.464
6.901
0.943
Legend: DFF = Days to first flowering, 50% DF = Days to 50% flowering, DH = Days to harvesting, AL = Anther length(µ), AB = Anther breadth(µ), SL = Stigma length(µ), SB = Stigma breadth(µ), PS = Pollen sterility%, PF = Pollen fertility%, SS = Spikelet sterility%, OCR = Out crossing rate%, FGP= Filled grains per panicle, UGP = Unfilled grains per panicle, GL = Grain length(mm), GB = Grain breadth(mm), GYH= Grain yield per hill (g).
52
Days to 50% flowering Analysis of variance for days to 50% flowering was highly significant indicating existence of considerable difference among the genotypes for this trait. The study showed that days to 50% flowering for the genotypes ranged from 81 to 103.667 days (Table 4). The maximum days to 50% flowering were found 103.667 days in genotype RG-BU-08-096 followed by genotype RGBU-08-097 and 56 and the minimum was recorded as 81 days in genotype BRRI dhan 28 followed by genotypes RG-BU-08-082, 79 and 76 (Appendix III) with mean value of 91.25 days (Table 4). The rest of the genotypes were different in flowering time and were of medium to long duration in flowering. Souroush et al. (2005) and Dorosti et al. (2004) found the similar results in rice. Days to harvesting Analysis of variance for days to harvesting was highly significant among the genotypes (Table 3). The maximum day to harvesting took 124 days and the minimum was recorded as 111 days with mean value of 116.78 days (Table 4). The genotype RG-BU-08-051, 54, 56, 58, 61, 63, 64, 66, 67, 70, 86, 87, 97 and 98 took the longest period for harvesting. The genotype RG-BU-08-052, 53, 65, 71, 73 and 99 took the minimum days for harvesting (111) (Appendix III). Anther length Analysis of variance for anther length was highly significant among the genotypes (Table 3). Anther length (µ) varied from 47.8 to 146.267µ with the mean of 96.318µ (Table 4). The longest anther was recorded in the genotype RG-BU-08-099, while the shortest was in RG-BU-08-082 (Appendix III). Ali et al. (2007) observed the similar results in rice.
53
Anther breadth Analysis of variance for anther breadth was highly significant among the genotypes for this trait (Table 3). Anther breadth (µ) varied from 14.333 to 36.2µ with the overall mean of 22.827µ (Table 4). The genotype RG-BU-08-099 attained the maximum anther breadth followed by the genotype RG-BU-08-087 and 75. The minimum anther breadth was obtained from the genotype RG-BU-08-086 followed by the genotype RG-BU-08-067 and 85 (Appendix III). Stigma length Analysis of variance for stigma length was highly significant for all genotypes (Table 3). Stigma length (µ) varied from 36.917 to 84.167µ with the overall mean of 58.176µ (Table 4). The longest stigma was recorded in RG-BU-08-099 while the shortest was in RG-BU-08-096 (Appendix III). Ali et al. (2007); Abdel-Ghani et al. (2005) and Chetia et al. (2000) found the similar results in rice. Stigma breadth Analysis of variance for stigma breadth was highly significant for all genotypes (Table 3). Stigma breadth (µ) varied from 13.417 to 32.917µ with the overall mean of 22.202µ (Table 4).
The
genotype RG-BU-08-066 attained the maximum stigma breadth and minimum was obtained in the genotype RG-BU-08-098 (Appendix III). Pollen sterility Analysis of variance for pollen sterility was highly significant for all genotypes (Table 3). The range of pollen sterility was 0.133 to 99.867% with the overall mean of 36.350% (Table 4). The highest pollen sterility 99.867% was recorded in RG-BU-08-085 followed by RG-BU-08-086, 57 and 65. The lowest pollen sterility (0.133 %) was recorded in the genotype RG-BU-08-062 54
and 69 followed by the genotypes RG-BU-08-060, 56 and 77. The rest of the lines were different and showed medium pollen sterility (Appendix III). Ali et al. (2007) and Chetia et al. (2000) found the similar results in rice. Pollen fertility Analysis of variance for pollen fertility was highly significant for all genotypes (Table 3). The range of pollen fertility was 0.133 to 99.867% with the overall mean of 63.930% (Table 4). The highest pollen fertility 99.867% was recorded in RG-BU-08-062 and 69. The lowest pollen fertility (0.133%) was recorded in RG-BU-08-085 followed by the genotypes RG-BU-08-086, 57 and 65. The rest of the lines were different and showed medium pollen fertility (Appendix III). Similar results were also reported by Madhavilatha et al. (2005) in rice. Spikelet sterility Analysis of variance for Spikelet sterility was highly significant for all genotypes (Table 3). Spikelet sterility ranged from 6.547 to 53.047% with the overall mean of 27.744 % (Table 4). The highest spikelet sterility 53.047% was recorded in the genotype RG-BU-08-099 followed by the genotypes RG-BU-08-061 and 96, respectively. The lowest spikelet sterility (6.547%) was recorded in the genotype RG-BU-08-079 followed by RG-BU-08-052, 94 and 76. The rest of the materials were different and showed medium spikelet sterility (Appendix III). Chetia et al. (2000) found the similar results in rice. Out crossing rate Analysis of variance for out crossing rate was highly significant for all genotypes (Table 3). The range of out crossing rate was 46.953 to 93.453% with the overall mean of 72.251% (Table 4). The highest out crossing rate (93.453 %) was recorded in the genotype RG-BU-08-079 followed by genotype RG-BU-08-052 and 94. The lowest out crossing rate (46.953%) was recorded in the 55
genotype RG-BU-08-099 followed by the genotype RG-BU-08-061 and 96. The rest of the lines were different and showed medium out crossing rate (Appendix III). Filled grains per panicle Analysis of variance for filled grains per panicle was highly significant for all genotypes (Table 3). The range of filled grains per panicle among the genotypes was 29 to 197.93 with mean value of 103.709 (Table 4). The highest fertile grain per panicle (197.93) was recorded in RG-BU-08097 and statistically similar to RG-BU-08-057 and 94, respectively. The genotype RG-BU-08099 produced the lowest filled grains per panicle (29) followed by the genotype RG-BU-08-075 and 66. The rest of the genotypes were different and showed diversed filled grains per panicle (Appendix III). Banumathy and Thiyagarajan (2005), Patil and Sarawgi (2005), Souroush et al. (2005) and Mahto et al. (2003) found the similar results in rice. Unfilled grains per panicle Analysis of variance for unfilled grains per panicle was highly significant for all genotypes (Table 3). The range of unfilled grains per panicle among the genotypes was 5.73 to 102.33 with mean value of 40.75 (Table 4). The maximum unfilled grains per panicle was found (102.333) in the genotype RG-BU-08-098 followed by genotype RG-BU-08-088 and the minimum (5.7333) was recorded in the genotype RG-BU-08-079 (Appendix III). Grain length Analysis of variance for grain length was highly significant for all genotypes (Table 3). Grain length varied from 6.267 to 14.053mm with the mean of 9.182mm. The longest grain (14.053mm) was recorded in the genotype RG-BU-08-099 which was similar to the genotype RG-BU-08-084 and 56, respectively while the shortest (6.267mm) was recorded in the genotype RG-BU-08-096
56
related to genotype RG-BU-08-076 and 82, respectively (Appendix III). Souroush et al. (2005) and Chang-JaeKi et al. (2002) found the similar results in rice. Grain breadth Analysis of variance for grain breadth was highly significant for all genotypes (Table 3). Grain breadth varied from 2.017 to 4.327mm with the overall mean 2.897mm. The genotype RG-BU08-099 attained the maximum grain breadth followed by genotype RG-BU-08-070, 88 and 79 respectively and minimum was obtained in the genotype RG-BU-08-087 followed by genotype RG-BU-08-060 and 65 (Appendix III). Similar results were also reported by Souroush et al. (2005) and Chang-JaeKi et al. (2002). Grain yield per hill Analysis of variance for grain yield per hill was highly significant for all genotypes (Table 3). The range of grain yield per hill was 7.820 to 38.907g with mean value of 26.464g (Table 4). The highest grain yield per hill (38.907g) was obtained from the genotype RG-BU-08-071 followed by the genotype RG-BU-08-052 and 94. Whereas the lowest yield per hill (7.820g) was obtained from the genotype RG-BU-08-075 followed by the genotype RG-BU-08-099 and 87. The rest of the lines are completely different for grain yield per hill (Appendix III). It is concluded that there was a wide genotypic variation among the genotypes for all the characters studied.
57
B.2. Variability in exotic rice Genotypes The extent of variability for any character is very important for the improvement of a crop through breeding. The estimates of genotypic variation (2g), phenotypic variation (2p), genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability (h 2) and genetic advance (GA) for different characters have been presented in Table 5. The highest 2g was found for unfilled grains per panicle (621.847) and the lowest magnitude of 2g was observed in grain length (5.483). The highest 2p was found for un-filled grains per panicle (658.148) and the lowest magnitude of 2p was observed in grain length (mm) (6.544). The GCV and PCV were the highest for days to 50% flowering (70.551 and 75.262) followed by spikelet sterility (60.216 and 74.077), days to first flowering (61.292 and 66.690) and pollen sterility (%) (45.739 and 48.438) (Table 5). High GCV and PCV for days to 50% flowering, spikelet sterility, days to first flowering and pollen sterility (%) indicated that selection of these traits would be effective. The GCV and PCV were the lowest for grain length (18.065 and 19.742) and filled grains per panicle (26.910 and 46.816). PCV were slightly higher than GCV in case of all the traits, indicating presence of environmental influence to some degrees in the phenotypic expression of the characters. Akanda et al. (1997) also reported similar result. High GCV and PCV were recorded for days to 50% flowering, spikelet sterility, days to first flowering and pollen sterility (%), but it was moderate for filled grains per panicle (26.910 and 46.816 mm), grain breadth (28.064 and 31.777 mm) and grain yield per hill (29.351 and 32.557 mm). The findings were supported by Saravanan and Senthil (1997) who observed high GCV and PCV for grains per panicle and moderate for hill height and 1000-grain weight in rice. Days to harvesting and days to first flowering exhibited low genotypic as well as phenotypic coefficient of variations in the present study, which may be due to presence of both positive and negative alleles in the population.
58
Table 5: Estimation of genetic parameters of 50 exotic rice genotypes with two check varieties
Characters MSG
MSE
DFF
136.738
50%DF
2g
2p
5.818
151.694 169.689 61.292 66.690 65.887 58.968
97.776
3.927
91.250
139.753 157.747 70.551 75.262 68.546 67.010
DH
74.572
1.279
116.776 378.518 393.791 45.193 46.948 72.275 17.558
PS
3718.338 125.606 36.350
546.874 621.746 45.739 48.438 69.560 56.878
SS
309.177
518.497 542.708 60.216 74.077 51.550 33.680
FGP
2110.328 163.708 103.709 33.353
UGP
1195.884 73.677
40.749
621.847 658.148 30.646 33.345 32.947 37.783
GL
4.054
0.024
9.182
5.483
GB
0.542
0.016
2.897
109.957 141.008 28.064 31.777 60.824 16.848
GYH
176.871
18.198
26.848
365.898 380.851 29.351 32.557 46.886 29.687
21.467
27.744
40.123
6.544
GCV
PCV
h2 b
Grand mean 81.846
GA
26.910 46.816 25.771 6.037
18.065 19.742 65.348 3.900
Legend: MSG = Mean sum of squares due to genotypes, MSE = Mean sum of squares due to error = 2e= Environmental variance, 2g = Genotypic variance, 2p = Phenotypic variance, GCV = Genotypic coefficient of variation, PCV = Phenotypic coefficient of variation, h2b = Heritability and GA = Genetic advance. DFF = Days to first flowering, 50% DF = Days to 50% flowering, DH = Days to harvesting, PS = Pollen sterility%, SS = Spikelet sterility%, FGP= Filled grains per panicle, UGP = Unfilled grains per panicle, GL = Grain length (mm), GB = Grain breadth (mm), GYH= Grain yield per hill (g).
59
High heritability was observed in days to harvesting (72.275), pollen sterility (69.560), days to 50% flowering (68.546), days to first flowering (65.887) but for filled grains per panicle (25.771), unfilled grains per panicle (32.947) heritability was low. Bhatti et al. (1998) reported high heritability for spikelets per panicle, 1000-grain weight and panicles per hill in rice. High heritability estimates have been found to be effective in the selection of superior genotypes on the basis of phenotypic performance. High heritability associated with high genetic advance was obtained in pollen sterility and unfilled grains per panicle. The result also had close agreement with the findings of Hossain and Haque (2003) and Iftekharuddaula et al. (2001). Grain yield per hill, filled grains per panicle and spikelet sterility had moderate heritability with moderate genetic advance. Kumar et al. (2006) also reported that traits exhibited high heritability along with high to moderate genetic advance suggesting that these characters could be of high importance for selecting better genotypes in rice improvement programme. The high heritability estimates along with low genetic advance indicates that non-additive type of gene action and genotypeenvironment interaction plays a significant role in the expression of the trait as observed in days to first flowering, days to 50% flowering, days to harvesting, grain length and grain breadth. Days to 50% flowering and days to first flowering had high genetic advance with high heritability along with moderate genetic advance and moderate heritability in pollen sterility, un- filled grains per panicle and spikelet sterility made these characters most effective in the selection of exotic rice.
60
B.3. Character Association Character association analysis among agronomic traits (Table 6) revealed that the genotypic correlation coefficients were higher than the corresponding phenotypic correlation coefficients in most cases. Accordingly, Bai et al. (1992) reported that the genotypic correlations were greater than the phenotypic values in medium durated rice varieties. From the study, grain yield was found positive and highly significant association with filled grain per panicle and grain length both at genotypic and phenotypic levels (Table 6). Similar associations in rice were also reported by Manuel and Palanisamy (1989) and Kennedy and Rangasamy (1998). Days to first flowering showed significant and positive correlation with days to 50% flowering at both genotypic and phenotypic level (Table 6). Days to harvesting showed highly significant positive correlation with days to first flowering and significant positive correlation with days to 50% flowering at genotypic and phenotypic level, respectively (Table 6). Pollen sterility had significant and positive association with spikelet sterility at both genotypic and phenotypic level as well as grain length showed significant and negative correlation with spikelet sterility at both genotypic and phenotypic level. Unfilled grains per panicle had highly significant and positive correlation with spikelet sterility at both genotypic and phenotypic level (Table 6). Unfilled grains per panicle and spikelet sterility (%) had significant and negative association grain yield per hill at both genotypic and phenotypic level as well as grain length showed highly significant and negative correlation with filled grains per panicle at both genotypic and phenotypic level (Table 6). Filled grains per panicle and grain yield per hill were showed highly significant and positive association with days to first flowering. Similar associations in rice were also reported by Ogunbayo et al. (2005).
61
Table 6: Genotypic (rg) correlation and phenotypic(rp) correlation coefficient among 50 exotic rice genotypes with two check varieties * indicates significant at 5% level of significance, ** indicates significant at 1% level of significance
Parameters 50%DF DFF 50% D F
DH
PS
SS
FGP
UGP
GL
DH
PS
SS
FGP
UGP
GL
GB
GYH
rg
0.42*
0.87**
0.84**
0.45*
0.73**
-0.53*
-0.74**
0.37*
0.76**
rp
0.49*
0.98**
0.88**
0.52*
0.76**
-0.64**
-0.78**
0.45*
0.82**
rg
0.47*
0.46*
0.25
0.40*
-0.29
-0.40*
0.20
0.42*
rp
0.54*
0.48*
0.28
0.41*
-0.35
-0.42*
0.24
0.60**
rg
0.92**
0.49*
0.79**
-0.58*
-0.80**
0.41*
0.83**
rp
0.95**
0.56*
0.83**
-0.70**
-0.85**
0.48*
1.06**
rg
0.48*
0.76**
-0.56*
-0.78**
0.39*
-0.80**
rp
0.54*
0.80**
-0.67**
-0.82**
0.47*
-1.05**
rg
-0.41*
0.60**
-0.42*
0.21
-0.43*
rp
-0.43*
0.66**
-0.44*
0.25
-0.41*
rg
-0.48*
-0.67**
0.34
0.67**
rp
-0.58*
-0.71**
0.40*
0.69**
rg
0.49*
-0.25
-0.51*
rp
0.52*
-0.30
-0.75*
0.34
0.70**
0.41*
0.76**
rg rp
GB
rg
0.34
rp
0.36
Legend: rg indicates genotypic correlation coefficient and rp indicates phenotypic correlation coefficient, DFF = Days to first flowering, 50% DF = Days to 50% flowering, DH = Days to harvesting, PS = Pollen sterility%, SS = Spikelet sterility%, FGP= Filled grains per panicle, UGP = Unfilled grains per panicle, GL = Grain length (mm), GB = Grain breadth (mm), GYH= Grain yield per hill (g).
However, the correlation study revealed that grain yield, days to first flowering, days to 50% flowering, days to harvesting, spikelet sterility (%), filled grain per panicle, unfilled grains per 62
panicle, grain length and grain breadth were the important characters to be considered in the selection for improvement of exotic rice genotypes.
Path Coefficient Analysis Partitioning of genotypic correlation of agronomic traits in exotic genotypes was shown in Table 7. From the path coefficient analysis (Table 7 and Fig. 4) showed that days to harvesting had maximum direct effect (0.956) on yield followed by filled grains per panicle (0.662), unfilled grains per panicle (0.356). The lowest direct effect on grain yield was exhibited by grain breadth (0.175) followed by days to 50% flowering (0.239). The highest negative indirect effects on grain yield were obtained by days to first flowering (-0.809). The results prescribed that highly significant positive correlation with positive direct effect was observed in days to harvesting, filled grains per panicle, unfilled grains per panicle, days to 50% flowering and grain breadth. The residual effect of the present study was 0.741 indicating 26% of the variability of grain yield per hill was contributed by the ten characters studied in the path analysis. Similar findings (R= 0.766) was found by Mojumder (2009).
63
Table 7: Partitioning of genotypic correlation with grain yield into direct (bold) and indirect effect in 50 exotic rice genotypes with two check varieties Parameters
DFF
50% DF
DH
PS (%)
SS (%)
FGP
UGP
GL
GB
GYH (g)
DFF
-0.809**
0.440
0.880**
0.851**
0.457
0.732**
-0.537
-0.743**
0.377
0.769**
50%DF
0.440
0.239
0.478
0.463
0.249
0.398
-0.292
-0.404
0.205
0.418
DH
0.880**
0.478
0.956**
0.925**
0.497
0.796**
-0.583
-0.808**
0.410
0.836**
PS (%)
0.851**
0.463
0.925**
-0.895**
0.481
0.770**
-0.564
-0.782**
0.396
0.809**
SS (%)
0.457
0.249
0.497
0.481
-0.259
0.414
-0.303
-0.420
0.213
0.435
FGP
0.732**
0.398
0.796**
0.770**
0.414
0.662**
-0.485
-0.672
0.341
0.696**
UGP
-0.537
-0.292
-0.583
-0.564
-0.303
-0.485
0.356
0.493
-0.250
-0.510
GL
-0.743**
-0.404
-0.808**
-0.782**
-0.420
-0.672**
0.493
-0.683**
-0.346
-0.706**
GB
0.377
0.205
0.410
0.396
0.213
0.341
-0.250
-0.346
0.175
0.358
R (Residual Effect) = 0.741; * = 5% level of significance and ** = 1% level of significance
Legend: DFF = Days to first flowering, 50% DF = Days to 50% flowering, DH = Days to harvesting, PS = Pollen sterility%, SS = Spikelet sterility%, FGP= Filled grains per panicle, UGP = Unfilled grains per panicle, GL = Grain length (mm), GB = Grain breadth (mm), GYH= Grain yield per hill (g).
64
0.741 R
-0.809 DF
GYH
0.239
0.956
50%D F
DH
0.440
0.880
0.478
-0.895 PS (%)
0.851
0.463
0.925
-0.259
0.662
SS (%)
0.457
0.732
0.249
0.398
0.497
0.796
0.481
0.770
0.396
0.356
FGP
-0.537
-0.292
-0.583
-0.564
-0.303
-0.683
0.175
GL
GB
UGP
-0.743
-0.404
-0.808
-0.782
0.377
0.205
0.410
0.396
-0.420 0.213
-0.485
-0.672 0.493
0.341 -0.250 -0.346
Figure 4: Path diagram of agronomic characters on grain yield per hill. Single arrow lines indicate path coefficients and double arrow lines indicate correlation coefficients. R = Residual effect. DFF = Days to first flowering, 50% DF = Days to 50% flowering, DH = Days to harvesting, PS = Pollen sterility%, SS = Spikelet sterility%, FGP= Filled grains per panicle, UGP
65
C.1. Genetic Diversity in Exotic Rice Genotypes Significant differences among genotypes in respect of agronomic traits are prerequisites of multivariate analysis. The replicated information of the present study of 50 exotic rice genotypes with two check varieties on analysis of variance revealed significant differences among all the genotypes for all the characters (Table 3). A considerable amount of genetic variability was observed and therefore, diversity analysis was carried out through multivariate analysis. Principal component analysis (PCA) Sixteen characters were considered for genetic diversity analysis. So sixteen eigen values of sixteen principal component axis and percentage of total variation accounted for them obtained from the principal component analysis are presented in Table 8. Due to out crossing characteristics, variability was generated in this crop. Quantification of such variability from genetic point of view is very scanty that the first axis largely accounted for the variation among the genotype (4.32) followed by second axis (7.66). The first five axes accounted for 58.10% of the total variation among the 16 characters describing 50 exotic rice genotypes with two check varieties while the former two accounted for 27.07%. These results are in agreement with the findings of Ogunbayo et al. (2005).
66
Table 8: Latent roots (Eigen values) and percentage of variation for corresponding 16 components characters in 50 exotic rice genotypes with two check varieties Latent roots
% of total variation accounted for
Cumulative percent
Days to first flowering
4.32
4.32
15.26
Days to 50% flowering
3.34
7.66
27.07
Days to harvesting
3.14
10.80
38.17
Anther length(µ)
2.88
13.68
48.35
Anther breadth(µ)
2.76
16.44
58.10
Stigma length(µ)
2.42
18.86
66.64
Stigma breadth(µ)
1.95
20.81
73.55
Pollen sterility%
1.80
22.62
79.92
Pollen fertility%
1.55
24.17
85.41
Spikelet sterility%
1.49
25.66
90.68
Out crossing rate%
1.03
26.69
94.31
Filled grains per panicle
0.64
27.33
93.60
Unfilled grains per panicle
0.46
27.78
96.62
Grain length(mm)
0.27
28.05
98.38
Grain breadth(mm)
0.17
28.22
99.52
Grain yield per hill (g)
0.07
28.30
100.00
Principal component axis
67
Construction of scatter diagram On the basis of principal axes I and II from the principal component analysis, a two way dimensional scatter diagram (Z1Z2) (Appendix IV) using component score I as X-axis and component score 2 as Y-axis was constructed, which is presented in Figure 4. The distribution of genotypes in scattered diagram (Fig. 5 and Fig. 6) was apparently distributed into seven groups/ clusters, which revealed that there exists considerable diversity among the genotypes.
48
38 7 15 36 21 35
52 26
47
32 31
34
24
12 4127 1 46 4 28 39 20 33 51 42 40 8 13 10 2 22 11 6 23 14 19 3 37 9
18
43
5
17 29 45
44
30
16
50
25
49
Figure 5: Scatter diagram of 50 exotic rice genotypes with 2 check varieties based on their principal component scores
68
48
VI
38
I
7 36 15 21 35
52 26 31III 34
24
43
5
17 29 45
Z2
18
30
VII
16
44
47
12 27 41 1 46 4 28 39 20 33 51 42 40 8 13 10 11 2 22 6 23 14 II 19 3 37 9
IV
32
50
25
49
V
Z1
Figure 6: Scatter diagram of 50 exotic rice genotypes with 2 check varieties based on their principal component scores superimposed with clustering
69
Non-hierarchical clustering of genotypes Non-hierarchical clustering using co-variance matrix among 50 exotic rice genotypes with two check varieties grouped them into seven clusters (Table 9). It may be concluded that these results were confirmatory with the clustering pattern of the genotypes obtained through principal component analysis (PCA). The distribution pattern indicated that the maximum genotypes (16) was included in cluster II followed by cluster I (11), cluster IV (22), cluster III (7), cluster VII (4), cluster VI (2) and cluster V (1). Genotypes in seven clusters ranged from 1 to 16 in different clusters.
Table 9: Distribution of 50 exotic rice genotypes with two check varieties in seven clusters Cluster Members
Name of Genotypes
I
11
RG-BU-08-055, 57, 65, 67, 71, 74, 81, 84, 85, 86
II
16
RG-BU-08-053, 54, 58, 60, 61, 63, 64, 69, 70, 72, 78, 89, 91, 92, 96, 97
III
7
RG-BU-08-068, 76, 79, 80, 82, 93, 95
IV
11
RG-BU-08-051, 52, 56, 62, 77, 83, 90, 94, 100, BRRI dhan 28, BRRI dhan 29
V
1
RG-BU-08-099
VI
2
RG-BU-08-088, 98
VII
4
RG-BU-08-059, 73, 75, 87
70
Principal coordinate analysis (PCO) Principal coordinate analysis was performed as an auxiliary of principal component analysis. Inter genotypic distances (D2) were obtained from principal coordinate analysis for all possible combinations between pairs of genotypes. The highest inter genotypic distance (6.448) was observed between RG-BU-08-085 and RG-BU-08-069 followed by the distance 6.444 observed between RG-BU-08-085 and RG-BU-08-062 (Table 10). The 10th higher distance (5.852) was observed between RG-BU-08-069 and RG-BU-08-065. The lowest distance was 0.380 which was observed between RG-BU-08-071 and RG-BU-08-057 followed by the distance 0.387 was observed between RG-BU-08-071 and 65 (Table 10). The 10th lower distance (0.613) was observed between RG-BU-08-074 and 68. Differences between the highest and lowest inter genotypic distances indicated the prevalence of genetic diversity among the rice genotypes. These inter genotypic distances were used in computation of intra-cluster distances from distance matrix of PCO. The statistical distances represent the index of genetic diversity among the clusters. The difference between the highest and lowest inter-genotype distance indicated the presence of variability among the 50 exotic rice genotypes with 2 check varieties.
71
Table 10: Ten higher and ten lower inter genotypic distance among the 50 exotic rice with 2 check varieties Sl. No.
Genotypic combination
Distances
A. 10 higher inter genotypic distance 01
RG-BU-08-085 - RG-BU-08-069
6.448
02
RG-BU-08-085 - RG-BU-08-062
6.444
03
RG-BU-08-084 - RG-BU-08-056
6.310
04
RG-BU-08-085 - RG-BU-08-077
6.222
05
RG-BU-08-086 - RG-BU-08-069
6.004
06
RG-BU-08-086 - RG-BU-08-062
5.968
07
RG-BU-08-069 - RG-BU-08-057
5.931
08
RG-BU-08-086 - RG-BU-08-060
5.915
09
RG-BU-08-086 - RG-BU-08-056
5.865
10
RG-BU-08-069 - RG-BU-08-065
5.852
B. 10 lower inter genotypic distance 01
RG-BU-08-071 - RG-BU-08-057
0.380
02
RG-BU-08-071 - RG-BU-08-065
0.387
03
RG-BU-08-086- RG-BU-08-065
0.473
04
RG-BU-08-084- RG-BU-08-055
0.502
05
RG-BU-08-063- RG-BU-08-054
0.524
06
RG-BU-08-065 - RG-BU-08-057
0.588
07
RG-BU-08-078- RG-BU-08-070
0.597
08
RG-BU-08-091 - RG-BU-08-063
0.604
09
RG-BU-08-092 - RG-BU-08-070
0.610
10
RG-BU-08-074 - RG-BU-08-068
0.613
72
genotypes
Canonical variant analysis (CVA) Canonical variant analysis was performed to obtain the inter cluster distances (Mahalanobis’s D 2 value). The values of inter cluster distance (D2) are presented in Table 11. Statistical distances represented the index of genetic diversity among the clusters. The highest inter-cluster distance was observed between cluster V and VI (36.37) followed by clusters V and VII (36.08) (Table 11). The lowest inter-cluster distance was observed between cluster IV and VI (0.56) followed by cluster II and IV (0.74). The maximum value of inter cluster distance indicated that the genotypes belonging to cluster V was far diverged from those of cluster VI. Similarly, the higher inter cluster values between clusters IV and V (35.92), cluster II and V (35.53), cluster III and V (35.14) and cluster I and V (34.05) indicated genotypes belonging to each pair of clusters were far diversed (Table 10). The minimum inter cluster divergence was observed between cluster IV and VI (0.56) indicating that the genotypes of these cluster were genetically closed. However, genotypes within the other pair of clusters indicated that they were less diverged. The inter cluster distances in all the clusters were higher than the intra cluster distances suggesting wider genetic diversity among the genotype of different groups. The results were agreemented with Rahman et al. (1997) and Singh and Chaudhuary (1985). Basher et al. (2007) also reported that inter cluster distances were larger than intra cluster distances in a multivariate analysis in rice. Based on the sixteen quantitative characters of 50 exotic rice genotypes with 2 check varieties, Principal coordinate analysis (PCO) was carried out to determine inter genotype distance (D2). The intra cluster distance, obtained by using the values of inter genotypes distance under each cluster as suggested by Singh and Chaudhuary (1985), and intra cluster distance was obtained from CVA were presented in Table 11.
73
Table 11: Average intra (Diagonal) and intercluster distances (D2) of 50 exotic rice genotypes with 2 check varieties I
II
III
IV
V
VI
I
1.65
II
10.62
0.13
III
4.34
6.44
1.52
IV
11.34
0.74
7.12
0.32
V
34.05
35.53
35.14
35.92
0
VI
11.16
0.88
6.90
0.56
36.37
1.08
VII
8.11
2.88
3.78
3.48
36.08
3.17
VII
2.08
The intra cluster distances ranged from 0 to 2.08 (Table 11). The highest intra-cluster distance was recorded in cluster VII (2.08) containing four genotypes followed by cluster I (1.65). The lowest intra-cluster distance was observed in cluster V (0) having only one genotype and the cluster II showed the second lowest inter cluster distance (0.13) having sixteen genotypes. It was favored to decide that intra-cluster diversity was the highest in cluster VII i.e., more heterogeneous and intra-cluster diversity was lower in cluster II i.e. comparatively homogenous. Higher inter and intra-cluster distances indicated higher genetic variability among genotypes between and within clusters, respectively. The minimum inter and intra-cluster distance indicated closeness among the genotypes of two clusters and within the cluster also. These relationships were also reflected in the scatter diagram (Fig. 4). Genotypes belonging to the distant clusters could be used in hybridization program for obtaining a wide spectrum of variation among the segregates (Mokate et al., 1998). It is more beneficial if crossing might be carried out between genotypes belonging to different groups if their genetic distances (D2) are greater than 12.5 (Wei et al., 1994). Thus it could be suggested that crosses might be made between genotypes belonging to the distant clusters for higher heterotic response.
74
In this present study, the inter cluster distances between cluster I and II with other cluster suggesting that crossing of genotypes of cluster I and II with desirable genotypes of other clusters would express heterotic effect.
Intra cluster mean Intra cluster mean for 16 characters are presented in Table 12. Among 16 characters cluster I had the highest estimates for only one character viz. days to 50% flowering (93.9). On the other hand, cluster I had one characters viz. pollen sterility (20.7%) which showed the lowest cluster mean value among 16 characters. In cluster II, the highest cluster mean value was achieved for two characters viz. days to harvesting (120.4) and spikelet sterility (34.4%). Among 16 characters cluster II which showed the lowest cluster mean value for three character viz. out crossing rate (65.9%) and filled grains per panicle (91.4). No highest cluster mean value was observed in cluster III but cluster III showed the lowest value only for two characters viz. days to first flowering (78.7) and grain yield per hill (23.8). The highest cluster mean value was observed in cluster IV for four characters viz. stigma breadth (25.4), pollen sterility (53.5%), out crossing rate (79.9) and grain breadth (3.1). The lowest cluster mean value was showed in cluster VI for days to 50% flowering (87.4), days to harvesting (111.8), anther length (83.7), pollen fertility (46.5%), spikelet sterility (20.1), unfilled grains per panicle (29.40) and grain length (8.1). In cluster V, the highest cluster mean value was achieved for six characters viz. days to first flowering (85.4), anther length (102.4), anther breadth (24.0), stigma length (64.3), unfilled grains per panicle (53.2) and grain length (9.8) but the cluster V shows lowest value for no characters. Cluster VI did not show any highest value but the lowest value for grain breadth (2.7).
75
Cluster VII showed three highest and three lowest cluster mean value viz. pollen fertility (82.4), filled grains per panicle (123.9), grain yield per hill (29.6) and anther length (21.0), stigma length (50.0) and stigma breadth (17.7), respectively.
Table 12: Cluster mean for 16 characters in 50 exotic rice genotypes with 2 check varieties Characters
I
II
III
IV
V
VI
VII
Max
Min
Days to first flowering
83.0
81.1
78.7
79.1
85.4
82.8
81.8
85.4
78.7
Days to 50% flowering
93.9
91.2
88.3
87.4
93.5
92.1
90.0
93.9
87.4
Days to harvesting
118.5
120.4
114.2
111.8
117.3
116.9
117.7
120.4 111.8
Anther length(µ)
96.1
97.1
95.5
83.7
102.4
96.9
95.6
102.4 83.7
Anther breadth(µ)
23.3
21.9
22.8
21.7
24.0
22.3
21.0
24.0
21.0
Stigma length(µ)
58.7
63.5
54.7
52.7
64.3
55.1
50.0
64.3
50.0
Stigma breadth(µ)
21.3
23.1
20.2
25.4
24.5
20.5
17.7
25.4
17.7
Pollen sterility%
20.7
47.6
41.6
53.5
37.3
32.7
21.3
53.5
20.7
Pollen fertility%
79.1
52.5
58.4
46.5
63.4
67.4
82.4
82.4
46.5
Spikelet sterility%
28.2
34.1
25.3
20.1
32.1
23.9
26.1
34.1
20.1
Out crossing rate%
71.8
65.9
74.7
79.9
67.9
76.1
73.9
79.9
65.9
Filled grains per panicle
99.0
91.4
96.2
108.1
107.5
121.5
123.9
123.9 91.4
Unfilled grains per panicle
39.9
46.3
32.2
29.4
53.2
42.5
45.7
53.2
29.4
Grain length(mm)
9.0
9.3
9.4
8.1
9.8
9.1
9.1
9.8
8.1
Grain breadth(mm)
2.9
3.0
2.8
3.1
2.9
2.7
2.7
3.1
2.7
Grain yield per hill (g)
27.2
25.5
23.8
26.6
25.9
28.9
29.6
29.6
23.8
It was clear from the Table 12 that the highest intra cluster means for yield were obtained from cluster V and four other most important reproductive characters were obtained from cluster IV. Therefore, more emphasis should be given on this cluster for selecting genotypes as a variety and as well as parents in crossing with other genotypes. 76
Contribution of different characters towards divergence of the genotypes The character contributing maximum to the divergence are given greater emphasis for deciding on the cluster for the purpose of further selection and the choice of parents for hybridization (Jagadev et al., 1991). Contributions of characters towards divergence obtained from canonical variant analysis are presented in Table 13. Vectors were calculated to represent the genotypes in the graphical form (Rao, 1952). The value of Vector I and Vector II revealed that both vectors had positive values for days to first flowering, days to 50% flowering, stigma length (µ), unfilled grains per panicle and grain breadth (mm) indicating the highest contribution of these traits towards divergence among 50 exotic rice genotypes with 2 check varieties of rice. In vector I other important character responsible for genetic divergence in the major axis of differentiation were days to harvesting, anther length (µ), anther breadth (µ), stigma breadth (µ), pollen sterility (%), pollen fertility(%), filled grain per panicle and grain yield per hill having positive vector values while rest of the characters played a minor role in the second axis of differentiation. In vector II other important character responsible for genetic divergence in the major axis of differentiation were spikelet sterility and out crossing rate (%) having positive vector values while rest of the characters played a minor role in the second axis of differentiation. Negative values in both vectors for the characters grain length (mm) had lower contribution towards the divergence. Kumari and Rangasamy (1997) concluded that grain yield per plant made the largest contribution to total divergence. Bidhan et al. (2002) found that days to 50% flowering, grain length and grain yield per plant were major yield contributing characters to rice genetic diversity.
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Table 13: Latent vectors for 16 characters of 50 exotic rice genotypes with 2 check varieties
Characters
Vector 1
Vector 2
Days to first flowering
0.364
0.491
Days to 50% flowering
0.191
0.051
Days to harvesting
0.306
-0.046
Anther length (µ)
0.145
-0.390
Anther breadth (µ)
0.034
-0.581
Stigma length (µ)
0.588
0.827
Stigma breadth (µ)
0.980
-1.603
Pollen sterility (%)
0.816
-1.001
Pollen fertility (%)
0.112
-0.045
Spikelet sterility (%)
-0.031
0.190
Out crossing rate (%)
-0.066
0.037
Filled grains per panicle
0.061
-0.411
Unfilled grains per panicle
0.493
0.702
Grain length (mm)
-0.053
-0.374
Grain breadth (mm)
0.023
0.021
Grain yield per hill (g)
0.386
-0.980
78
Comparison of result based on different multivariate techniques Results obtained from different multivariate techniques were super imposed in Figure 4 from which it could be concluded that all techniques gave more or less similar results and one technique supplemented and confirmed the results of the others. The cluster pattern of D 2 analysis through nonhierarchical clustering has taken care of simultaneous variation in all the characters under study. However, the distribution of genotypes in different clusters of the D 2 analysis had followed more or less similar trend of the principal component score 1 and principal component score 2 of the principal component analysis. D2 analysis and principal component analysis were found to be alternative methods in giving information regarding clustering pattern of genotypes. Nevertheless, the canonical variant analysis (CVA) provides information regarding the contribution of characters towards divergence of exotic rice genotypes.
Selection of genotypes as parent for hybridization programme Genotypes were to be selected on the basis of specific objectives and no common criterion can be considered for selection of genotypes. Buu and Tuan (1989) suggested use of diverged genotypes in the hybridization program in rice. Considering the magnitude of genetic distance, contribution of different characters towards the total divergence and magnitude of cluster means for different characters performance, among fifty the following thirteen genotypes were considered to perform better if used in hybridization programme. The genotypes are RG-BU-08-057, 65, 67, 71, 85 & 86 from cluster I, genotypes RG-BU-08-061, 69 & 96 from cluster II, genotypes RG-BU-08-094 from cluster IV, genotype RG-BU-08-099 from cluster V and genotypes RG-BU-08-088 & 98 from the cluster VI might be selected.
79
CHAPTER V SUMMARY The experiment was conducted with 50 exotic rice genotypes with two check varieties at the BSMRAU experimental field to study characterization and genetic diversity of 50 exotic rice genotypes and to find out the association between the agronomic traits. The salient findings of the present study have been summarized below. The genotypes RG-BU-08-072 showed dark red and RG-BU-08-076, 80, 82 and 99 showed light red panicle in colour. The genotypes RG-BU-08-072, 76, 78, 79, 82, 91 and 99 showed closed panicle type. The genotypes RG-BU-08-052, 54, 58, 62, 65, 66, 68, 69, 70, 73, 74, 75, 80, 84, 90, 92, 95 and 97 showed intermediate panicle type and remaining genotypes showed open type panicle. The genotypes RG-BU-08-099 showed the highest seed length (14.053mm) and genotype RG-BU-08096 had the lowest seed length (6.267mm). The genotypes RG-BU-08-099 showed the highest seed breadth (4.327mm) and genotype RG-BU-08-087 had the lowest seed breadth (2.017mm). Seven genotypes were sterile (genotypes RG-BU-08-057, 65, 66, 67, 71, 73 and 86), four genotypes were partially sterile (PS) (genotypes RG-BU-08-055, 76, 81 and 84), nine genotypes were partially fertile (PF) (genotypes RG-BU-08-068, 74, 75, 79, 80, 82, 93, 95 and 99), five genotypes were fertile (F) (genotypes RG-BU-08-070, 78, 87, 96 and 97) as well as twenty four genotypes were fully fertile (FF) (RG-BU-08-051, 52, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 69, 72, 77, 83, 88, 89, 90, 91, 92, 94, 98 and 100). Analysis of variance showed significant for all the genotypes in respect to 16 characters, indicating considerable variation among them. Regarding mean performance, the genotype RG-BU-08-096 took the longest period for first flowering (98) followed by genotype RG-BU-08-063, 91 and 97, respectively and the genotype 66 had the minimum days for first flowering. The longest anther was 80
recorded in genotype RG-BU-08-099, while the shortest was recorded in genotype RG-BU-08-082. The highest pollen sterility (99.867%) was recorded in genotype RG-BU-08-062 and 69. The highest spikelet sterility (53.047%) was recorded in the genotype RG-BU-08-099 followed by RG-BU-08061 and 96. The lowest spikelet sterility (6.547%) was recorded in genotype RG-BU-08-79. The highest fertile grains per panicle (197.933) was recorded in RG-BU-08-097 and closely related to RG-BU-08-057 and 94, respectively. The highest grain yield per hill produced by the genotype 71 (38.907g) which was closely related to genotype 52 and 94 whereas the lowest grain yield per hill obtained from the genotype RG-BU-08-075 followed by genotype RG-BU-08-099 and 87. The highest 2g was found for unfilled grains per panicle (621.847) and the lowest magnitude of 2g was observed in grain breadth (5.483 mm). The highest 2p was found for unfilled grains per panicle (658.148) and the lowest magnitude of 2p was observed in grain length (6.544mm). High GCV and PCV for days to 50% flowering, spikelet sterility, days to first flowering and pollen sterility indicated that selection of these traits would be effective. The high heritability estimates along with low genetic advance indicates that non-additive type of gene action and genotype -environment interaction plays a significant role in the expression of the trait as observed in days to first flowering, days to 50% flowering, days to harvesting, grain length and grain breadth. Pollen sterility and unfilled grains per panicle had high heritability with high genetic advance along with moderate heritability with moderate genetic advance in grain yield per plant, filled grains per panicle and spikelet sterility making these characters most effective in the selection of exotic rice.
Filled grain per panicle with grain yield as well as unfilled grains per panicle with spikelet sterility showed significant and positive correlation but grain length showed highly significant and negative correlation with filled grains per panicle both at genotypic and phenotypic level. Days to harvesting had maximum direct effect (1.06) on yield followed by grain length (0.76) filled grains per panicle 81
(0.69), days to first flowering (0.82mm), days to 50% flowering (0.60) and pollen sterility (1.05mm). Sixteen agronomic characteristics of fifty exotic rice genotypes with two check varieties were evaluated to study the genetic divergence through multivariate analysis. Genotypes were grouped into seven different clusters. PCA showed 58.10% of the total variation among the 16 characters against first five eigen values. The highest inter genotypic distance 6.448 was observed between the genotype RG-BU-08-085 and 69. The lowest inter cluster distance was observed between cluster IV and VI (0.56) followed by cluster II and IV (0.74). The higher inter cluster values between cluster V and VI (36.37), cluster V and VII (36.08), cluster IV and V (35.92), cluster II and V (35.53), cluster III and V (35.14) and cluster I and V (34.05) indicated genotypes belonging to each pair of clusters were far diversed. In cluster II, the highest cluster mean value was achieved for two characters viz. days to harvesting (120.4) and spikelet sterility (34.4%). The highest cluster mean value was showed in cluster V viz. days to first flowering (85.4), anther length (102.4), anther breadth (24.0), stigma length (64.3), unfilled grains per panicle (53.2) and grain length (9.8) as well as the highest cluster mean value was revealed in cluster IV for stigma breadth (25.4), pollen sterility (53.5%), out crossing rate (79.9) and grain breadth (3.1). Considering the magnitude of genetic distance, contribution of different characters towards the total divergence and magnitude of cluster means for different characters performance, genotypes RG-BU-08-057, 65, 67, 71, 85 & 86 from cluster I, genotypes RG-BU-08-061, 69 & 96 from cluster II, genotypes RG-BU-08-094 from cluster IV, genotype RGBU-08-099 from cluster V and genotypes RG-BU-08-088 & 98 from the cluster VI might be selected as a suitable parent for future hybridization programme.
82
CHAPTER VI CONCLUSION
Analysis of variance showed that there were significant variations among the genotypes for 16 characters studied.
Among the fifty exotic rice genotypes the genotype RG-BU-08-072 showed dark red and RG-BU08-076, 80, 82 and 99 showed light red panicle in colour. The genotype RG-BU-08-099 and RGBU-08-096 showed the highest and the lowest seed length. Seven genotypes RG-BU-08-057, 65, 66, 67, 71, 73 and 86 were sterile and twenty four genotypes RG-BU-08-051, 52, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 69, 72, 77, 83, 88, 89, 90, 91, 92, 94, 98 and 100 were fully fertile.
The genotype RG-BU-08-096 took the longest period and RG-BU-08-066 had the minimum days for first flowering. The highest pollen sterility was recorded in RG-BU-08-085 and the highest grain yield per hill obtained from RG-BU-08-071.
The highest 2g and 2p was found for unfilled grains per panicle and filled grains per panicle. High heritability and GA was observed in days to 50% flowering and days to first flowering along with moderate heritability with moderate genetic advance in pollen sterility, un- filled grains per panicle and spikelet sterility suggested that these characters could be transmitted to the hybrid progeny and phenotypic selection based on these would be effective.
The 50 genotypes with two check varieties were grouped into seven clusters. Considering the magnitude of genetic distance, contribution of different characters towards the total divergence and magnitude of cluster means for different characters performance, the genotypes RG-BU-08-057, 65, 67, 71, 85 & 86 from cluster I, genotypes RG-BU-08-061, 69 & 96 from cluster II, genotypes RGBU-08-094 from cluster IV, genotype RG-BU-08-099 from cluster V and genotypes RG-BU-08-088 & 98 from the cluster VI might be selected as a suitable parent for future hybridization programme.
83
RECOMMENDATION The genotypes RG-BU-08-085, 057, 65, 66, 67, 71, 73 and 86 may be used as CMS lines due to their higher pollen sterility. The genotypes RG-BU-08-051, 52, 53, 54, 56, 58, 59, 60, 61, 62, 63, 64, 69, 72, 77, 83, 88, 89, 90, 91, 92, 94, 98 and 100 might be selected as restorer lines due to their higher pollen fertility. The genotypes RG-BU-08-057, 61, 65, 67, 69, 71, 85, 86, 88, 94, 96, 98 and 99 may be used as divergent genotypes as parent in future hybridization programme, which may produce desirable segregants.
84
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