Exploration of quality tea cultivars with high yield ...

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Tea (Camellia sinensis/assamica) is the most important crop species ofthe genus .... black tea of each clone and allowing it to stand for 3 min. Tea tasters' sniffed ...
Two and a Bud 58:127-131,

2011

RESEARCH PAPER

Exploration of quality tea cultivars with high yield potential RK. Bordoloi,

D. Thakur, P. Tamuli, and T.S. Barmanl Department of Plant Physiology and Breeding, Tocklai Experimental Station, Tea Research Association, Jorhat - 785 008, Assam, India

ABSTRACT With the objective of developing quality clones with high yield potential, five quality tea plants were selected on the basis of morphological features from seed jat populations. Each plant was multiplied through vegetative propagation at Tocklai. A long term agriculture trial was established in the Growth Habit Plot at Tocklai during the year 2006/2007 with the popular clones TV 1, S.3A13 and Teenali 17/1/54 as controls. The cultural operations for bringing up of young tea were followed as per TRA recommendations and the growth behavior of these clones was studied in vivo. The first frame formation prune (FFP) was given in January, 2009, and the final FFP was given in January, 2011. Clones were evaluated by Percentages of brightness, compared with the control be released to the industry

comparing the crop yield, pruning litters, catechin profiling and organoleptic analysis. theatlavins (TF), thearubigins (TR) and total catechin of made tea were quantified and clones. From this long term agricultural trial, clones showing better performance would for mass plantation.

INTRODUCTION

Tea is a strictly cross-pollinated crop and selected genotypes are multiplied vegetatively following the technique of vegetative propagation (VP) developed by Tunstall (1931). The success in the breeding of any crop depends on the availability of diverse genotypes. The cultivars are developed either by selection and evaluation of the existing genotypes or by the creation of new variability. The importance of collecting diverse germplasms at Tocklai has been realized since the establishment of the station (Bezbaruah and Dutta 1977). Tocklai has the second largest collection of tea germplasms (around 1800) but yet seems to be quite small in view of the highly heterogenous nature of the available tea population. It is estimated that the chance of getting an acceptable clone is one out of 40000 to 100000 gennplasms or even more (Wight, 1956). Exploration of quality tea cultivars has been given due importance in the ongoing tea improvement program at Tocklai.

Tea (Camellia sinensis/assamica) is the most important crop species ofthe genus Camellia, which has 82 species (Sealy, 1958) and accounts for more than 325 species (Mondal et al.,2002). It indicates a wide genetical variation and high outbreeding nature of the genus. But only 3 of them are being used for manufacturing oftea (Barua 1965). The Camellia assamica (Assam tea) is indigenous to Assam (India) and is characterized by tall trees with large leaves. The Chinatype Camellia sinensis (China tea) is indigenous to China and is bushy in nature with small leaves and multiple stems. Another plant introduced in Assam for cultivation, commonly known as Cambod or Indochina tea, which is not very different from the Assam plant, was considered by Wight (1962) to be a sub-species of the Assam plant which he designated as Camellia assamica sub species lasiocalyx (Planch MS). Cambod or Indochina tea has been treated as an intermediate between the China and Assam

Since 1949, through introduction, selection and hybridization, Tocklai Experimental Station, has released 31 Tocklai Vegetative (TV) and 153 TRA/garden series clones for commercial cultivation. In field trials, the yield of the released clones has been found superior over the popular seed varieties like Betjan, Khorijan, Tingamira etc. Out of 31 TV clones development of only one quality clone TV21 indicates the

types of tea plant. Presently, over 600 cultivated varieties are available world-wide, of which many have unique traits (BTRI. 2003; Mondal et al., 2004).

1

Corresponding author e-mail: [email protected] 127

greater success in the breeding for yield than for quality. There could be several reasons for it, such as non availability of enough genetically diverse and properly evaluated germplasms, inadequate quality evaluation techniques, lack of genetic information about quality components, diverse quality needs of the consumers and/or variable emphasis on breeding objectives etc. (Singh, 1980).

were quantified for catechins and caffeine by using HPLC with Luna 51!phenyl-hexyl-phenomenax column (4.5 x 250 mm) and UV-Visible detector at 278 nm. The solvent system used was solvent "A" (2.0 % acetic acid and 9.0 % acetic acetonitrile); solvent "B" (80 % acetonitrile) as described in ISO (ISO committee draft, 1999). The chromatographic peaks were identified and estimated by 'comparing the retention times and areas ofthe standard catechins expressed as percentage dry weight.

The paper describes the high yielding quality clones developed at Tocklai using yield potential, biochemical and organoleptic taste analysis.

Fermentability of green leaf Chloroform test was carried out on harvested two leaves

MATERIALS AND METHODS

and a bud shoots sampled from five randomly selected bushes from each plot to determine the fermentability of clones following the methods described by Sanderson (1964). Fermentability was scored based on the change in colour after 1-2 hours using a 4-point scale as bright red brown (fast fermented), dull brown (moderate fermented), greenish tinge (poor fermented) and green (non-fermented).

Selection of mother bushes and propagation The mother bushes were selected based on some ideal morphological and numerical parameters having positive correlation with the desired traits (high yield and quality potential, free from pest and diseases) as described by Barua (1989). To develop quality clones with high yield potential, five promising tea plants were selected from seed progenies. The selected plants were coded as St.652, St.659, St.660, St.662 and St.663. All plants were multiplied by vegetative propagation. Mortality percentage was recorded after 5 months of propagation. Plants of uniform size were selected for transplanting to the experimental site. Now onwards each plant will be considered as clones (unreleased)

Biochemical and organoleptic analysis of made tea Theatlavins (TF), thearubigins (TR) and total colour (TC) of all clones were estimated frop" r:TC black tea by 1984). Catechin spectrophotometric method (Ullah e. profiling of the new clones was quanti tied and compared with the quality clone S.3A/3.Tasters' evaluation of black tea was performed. Infusions were prepared by pouring 150 ml of boiling distilled water into a cup containing 3 gm of black tea of each clone and allowing it to stand for 3 min. Tea tasters' sniffed and tasted the infusions, including tea leaves. Tea tasters scored their sensory evaluations of brightness, briskness, strength and valuation on a scale of 0-10 for each parameter. Alternatively, samples of made tea were sent to J. Thomas & Co. Private Ltd., Kolkata, India for oorgano1eptic evaluation.

Establishment of Long Term Trial (LTT) The tea cultivars were planted in a randomized complete block design field trial. Spacing was 105cm x 60cm accommodating 30 plants per replication. The trial was established at Growth Habit Plot, Tocklai (26°45'N, 94°13 'E) during November, 2006, with the popular clones TV 1, S.3N3 and Teenali 17/1/54 as controls.

RESULTS AND DISCUSSIONS The young tea bringing up such as cultivation, centering, pruning, plucking, manuring, drainage etc. were followed as per practices recommended by TRA (Tea Field Management 2011). The first FFP was given in January, 2009 and the [mal FFP was given after two years i.e. in January, 2011.

Some of the important morphological characteristics of the clones are presented in Table 1. Tea clone St. 660 possessed high pubescences in the lower surface of young leaves (Table 1). But other clones showed low to medium quantities of pubescence, except Teenali-17/l /54. Pubescence varies widely between genotypes. In some clones hairs develop only on the midrib but in highly pubescent clone it spreads on the lower surface of leaves and forms a dense covering on the entire lamina. Density of pubescence has positive correlation with quality (Wight and Barua, 1954; Wight et al., 1963; Venkataramani and Padmanabhan, 1964). Wight and Gilchrist (1961) reported that pubescence produced tips in orthodox manufacturing but in C.T.C. manufacturing, there was no correlation betwee 1 pubescence and quality. Variations in shoot length are observed among the clones (Table I). Amma (1975) observed good correlation between lengths of the growing

Crop yields and pruning litters weight Morphological characters of the clones were studied and recorded. Crop yield data were recorded from 2008 to 2011. Plucking was done at 7 days intervals. The green leaf yield was converted into kg made tea per hectare (KMTH). Pruning litters weight was recorded after 15t and 2nd FFP and converted to kg/ha.

Total polyphenols of green leaf Two grams of two and a bud shoots was extracted with 70% methanol at 70°C. The solvent extracts of tea leaves 128

Table 1. Attributes

and establishment

of clones used in the field trial



cence Fast T.E. Fast Nt4Large il NBA. Fast Ovate PigmenShoot Bullation FermenShoot PubesLeaf Tocklai Source Ovate Medium Green Nil TS.379 Lenceolate Low Green4 Green3 Low Medium TS.497 Prominent fast prominent fermenting Mortality ability Progeny length High prominent to green Coppery Ugh Moderately Broad Borsapori ly fermenting Marge Large (silvery fermenting termenting Moderately (%) Elliptical Merge Lar geMedium sho ots, of Type oftation clones fermenting St 659

yellow

kg/ha), St. 660 (2489 kg/ha) and St. 662 (2280 kglha). In 2011, the young tea bushes were pruned (2nd FFP) and only 25 rounds of plucking were completed. In the year of 2nd FFP, the crop yield was highest in St. 663 (2573 kglha) foHowed by St.660 (2166 kg/ha), St.662 (1974 kg/ha), St.652 (1763 kglha), St. 659 (1288 kg/ha). The crop yields of clones TV1, S.3A/3 and TA 17/1.54 were 1477, 1990 and 1688 kglha respectively in the year of2nd FFP, 2011.

shoots and yields particularly in small-leaf China and Chinahybrid populations. The fermentation time of tea leaves play an important role in determining the quality of made tea. Emersion of yielding shoots in liquid chloroform is practiced in many countries for screening bushes for fermentation ability (Toyao and Katsuo, 1972). Chloroform test showed fast fermenting behavior of clones St. 659, 660, 662 and 663 (Table I). Mortality rate of the young plants under field condition were recorded after 5 months of propagation and results are presented in Table I. All the clones under field condition showed very good growth and the percentage of mortality was insignificant. Crop yields and pruning

Table 2. Yield of made tea kg per hectare clones from 2008-2011

Clone

2008

(KMTH)

KMTH of new clones 2009 20 I0 20 II

of new

Mean

(UP) (I stFFP) (UP) (2 nd FFP) . St. 652 1174 1531 2627 1763 1774 St. 659 558 858 1307 1288 1003 St. 660 1651 1392 2489 2166 1924 St. 662 1298 1418 2280 1974 1742 St. 663 1851 1654 2652 2573 2182 TV 1 1102 1227 1457 1477 1315 S.3A/3 825 1283 2186 1990 1571 TA 17/\/54 825 1222 1809 1688 1386 CD for clone 5% 357.318 1% 525.22 CV %: 12.59

litter weights

The crop yields in made tea kglha from 2008 to 20 II of each clone are presented in Table 2 and Fig. 1. In the unpruned year 2008, 29 rounds of plucking were done. In 2008, the crop yield was highest in St. 663 (1852 kg/ha) foHowed by St. 660 (165Ikglha) and St. 662 (1298 kg/ha). In 2009, young tea bushes were pruned (1 st FFP) and 24 rounds of plucking were completed. The crop yield was highest again in St. 663 (1655 kg/ha) foHowed by St. 652 (1532 kglha), St. 662 (1418 kg/ha) and St. 660 (1393 kg! ha). In 2010, the bushes were kept unpruned and only 27 rounds of plucking were completed. The crop yield was highest in St. 663 (2652 kglha) followed by St. 652 (2627

In respect of yield potential (average of 4 years) the clones were in the order ofSt. 663 > St. 6bo > St. 652> St. 662 > S.3A/3 >TA 17/1/54 >TVI> St. 659. The mean crop yields

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4). However, the quality of CTC black tea of all clones is acceptable as the TF is above 1% and TR is above 15%.

of clones except St.659 were significantly higher (P