Genetic Resource Management in Fruit Crops 25 Years of Accomplishment

Genetic resource management in litchi – Three decades of accomplishment at ICAR RCER, Research Centre, Ranchi

Bikash Das

ICAR Research Complex for Eastern Region, Research Centre, Ranchi

Plandu, Ranchi

Abstract

Litchi is an important fruit crop of the Eastern plateau and hill agro-climatic zone. Visualizing need for location specific high yielding cultivars in the region, the programme on genetic resource management in litchi was initiated at the ICAR Research Complex for Eastern Region, Research Centre, Ranchi (formerly Horticulture and Agro-forestry Research Programme, Ranchi) in the very first year of its establishment.Efforts on collection and conservation of germplasm have resulted in augmentation of 53 genotypes in the field gene bank. Out of them, 17 genotypes which have attained full bearing potential have been characterized based on 83 characters (Tree characters-12, Leaf characters-20, Inflorescence characters-12, Fruit characters-31, Seed characters-9, Growing Degree Days requirement). Classification of genotypes through D2-analysis based on leaf biochemical characters like total free amino acid, total phenol, total soluble protein and total carbohydrate was found to be insufficient, although the method holds promise by inclusion of more number of biochemical parameters. Studies on genetic variability among the genotypes indicated that characters like ascorbic acid content, seed and peel weights and their percentage, peel thickness, seed shape index and seed volume had high heritability as well as high genetic advance. And hence are governed by additive gene action. Stability analysis of economically important traits indicated that stable varieties Rose Scented can be a source for improvement of yield, tree girth and fruit length while Purbi can be source for improvement in fruit weight and fruit diameter in addition to plant yield and tree girth. Changes in yield pattern of different varieties indicated yield stabilization after 20 years. Based on performance evaluation of different genotypes, the litchi cv. Shahi has been recommended at Group Workers Meeting of All India Coordinated Research Project on Subtropical Fruits for cultivation in Jharkhand and Bihar. Apart from this, a distinct variety Swarna Roopa has also been released from the centre for cultivation in Jharkhand.

Introduction

Collection and conservation of germplasm

The collection and conservation of litchi germplasm was initiated soon after the establishment of the station in May 1979 with the collection of 15 litchi cultivars from BAC Sabour and Dholi. Intensive survey of litchi orchards conducted in Ranchi, Samastipur, Darbhanga, Muzaffarpur, and Motihari districts to locate superior clones during 1986 increased the total germplasms up to 24. During 1987, the germplasm holding was raised upto 26 through the collection of identified materials and materials from the known sources. Subsequently fine-grid survey was undertaken in the variability region and 27 more accessions were identified and collected.

Major collections made in litchiat ICAR RCER, RC, Ranchi

Year of augmentation / Areas from where exploration/collection augumented / Number of germplasms augumented / Scientist involved in the identification and augumentation
1980 / Bihar, West Bengal and Chhatisgarh / 15 / Dr. I. S. Yadav
Dr. H. P. Singh
1985 / Bihar / 5 / Dr. H. P. Singh
1998 / North Bihar / 26 / Dr. Mathura Rai
Dr. K.K. Gangopadhyay
2002 / North Bihar / 36 / Dr. Vishal Nath
Dr V.K. Gupta (NBPGR)

At present the total number of germplasm holding in the field gene bank is 53out of which 30 varieties have started fruiting.

Collection and conservation of litchi Germplasms

Coll no. / I C No. / Cultivar / Village / P.O. / District / State
Litchi 1 / 333446 / Ajhauli / Sabour / Sabour / Bhagalpur / Bihar
Litchi 2 / 333447 / Green / Sabour / Sabour / Bhagalpur / Bihar
Litchi 3 / 333448 / Purbi / Sabour / Sabour / Bhagalpur / Bihar
Litchi 4 / 333449 / Late Bedana / Sabour / Sabour / Bhagalpur / Bihar
Litchi 5 / 333450 / China / Sabour / Sabour / Bhagalpur / Bihar
Litchi 6 / 333451 / Bedana / Sabour / Sabour / Bhagalpur / Bihar
Litchi 7 / 333452 / Deshi / Sabour / Sabour / Bhagalpur / Bihar
Litchi 8 / 333453 / Dehradun / Sabour / Sabour / Bhagalpur / Bihar
Litchi 9 / 333454 / Kasba / Sabour / Sabour / Bhagalpur / Bihar
Litchi 10 / 333455 / D’Rose / Dholi / Dholi / Muzaffarpur / Bihar
Litchi 11 / 333456 / Rose Scented / Dholi / Dholi / Muzaffarpur / Bihar
Litchi 12 / 333457 / Longia / Dholi / Dholi / Muzaffarpur / Bihar
Litchi 13 / 333458 / Shahi / Dholi / Dholi / Muzaffarpur / Bihar
Litchi 14 / 333459 / Trikolia Sel / Trikolia / Trikolia / Motihari / Bihar
Litchi 15 / 333460 / CHES-2 / BCKV / Mohanpur / Calcutta / West Bengal
Litchi 16 / 333461 / Bombaiya I / BCKV / Mohanpur / Calcutta / West Bengal
Litchi 17 / 333462 / Bombaiya II / BCKV / Mohanpur / Calcutta / West Bengal
Litchi 18 / 333463 / Swarna Roopa / Plandu / Rajaulatu / Ranchi / Jharkhand
Litchi 19 / 333464 / Yogada I / Club Road / Doranda / Ranchi / Jharkhand
Litchi 20 / 333465 / Yogada II / Club Road / Doranda / Ranchi / Jharkhand
Litchi 21 / 333466 / Sarguja I / ARS / Ambikapur / Ambikapur / Chhatisgarh
Litchi 22 / 333467 / Sarguja II / ARS / Ambikapur / Ambikapur / Chhatisgarh
Litchi 23 / 333468 / CHES-3 / Club Road / Doranda / Ranchi / Jharkhand
Litchi 24 / 333469 / CHES-4 / Club Road / Doranda / Ranchi / Jharkhand
Litchi 25 / 333470 / CHES-5 / Club Road / Doranda / Ranchi / Jharkhand
Litchi 26 / 333471 / CHES-6 / Club Road / Doranda / Ranchi / Jharkhand
Litchi 27 / 333472 / Late Large / Sabour / Sabour / Bhagalpur / Bihar
Litchi 28 / 333473 / Lal Bombaiya / Sabour / Sabour / Bhagalpur / Bihar
Litchi 29 / 333474 / Sri Koliya Green / Sabour / Sabour / Bhagalpur / Bihar
Litchi 30 / 333475 / CHES-7 / Namkum Bazar / Khijri / Ranchi / Jharkhand
Litchi 31 / 333476 / CHES-8 / Patra Toli / Khijri / Ranchi / Jharkhand
Litchi 32 / 333477 / Mandraji / Patharchatta / Pathchatta / Udham Singh Nagar / Uttarkhand
Litchi 33 / 333478 / Maclean / Patharchatta / Pathchatta / Udham Singh Nagar / Uttarkhand
Litchi 34 / 333479 / Late Seedless / Patharchatta / Pathchatta / Udham Singh Nagar / Uttarkhand
Litchi 35 / 333480 / Late Large Green / Patharchatta / Pathchatta / Udham Singh Nagar / Uttarkhand
Litchi 36 / 333481 / Early Seedless / Patharchatta / Pathchatta / Udham Singh Nagar / Uttarkhand
Litchi 37 / 333482 / Calcuttia / Patharchatta / Pathchatta / Udham Singh Nagar / Uttarkhand
Litchi 38 / 333483 / Muzaffarpur / Patharchatta / Pathchatta / Udham Singh Nagar / Uttarkhand
Litchi 39 / 333484 / CHES-9 / Kharsidag / Tetari / Ranchi / Jharkhand
Litchi 40 / 333485 / CHES-10 / Namkum Bazar (Tea garden) / Khijri / Ranchi / Jharkhand
Litchi 41 / Bombaiya III / BCKV / Mohanpur / Kalyani / West Bengal
Litchi 42 / 333487 / Dehradun / FRS / Saharanpur / Saharanpur / U.P.
Litchi 43 / 333488 / Piyaji / FRS / Saharanpur / Saharanpur / U.P.
Litchi 44 / 333489 / Sabour Sel / Sabour / Sabour / Bhagalpur / Bihar
Litchi 45 / 333490 / Sabour Purbi / Sabour / Sabour / Bhagalpur / Bihar
Litchi 46 / 333491 / Sabour Madhu / Sabour / Sabour / Bhagalpur / Bihar
Litchi 47 / 333492 / Bedana IV / Sabour / Sabour / Bhagalpur / Bihar
Litchi 48 / 333493 / Ellaichi / Sabour / Sabour / Bhagalpur / Bihar
Litchi 49 / 333494 / Rukka Coll / Rukka / Rukka / Ranchi / Jharkhand
Litchi 50 / 333495 / Nafarpal / BCKV / Mohanpur / Kalyani / West Bengal
VKG-8/1 / 209852 / Shahi Sel. / Narayanpur / Pusa / Samastipur / Bihar
VKG-8/5 / 209856 / Shahi Sel. / Ladaura / Kalyanpur / Samastipur / Bihar
VKG-8/6 / 209857 / Shahi Sel. / Ladaura / Kalyanpur / Samastipur / Bihar

Evaluation and characterization

a. Based on tree characters and yield

Different litchi genotypes vary in their tree growth characters. Seventeen genotypes collected in the first phase were characterized on the basis of tree growth and foliage characters as per IPGRI Descriptor after attaining more than 20 years of age (Adult bearing stage).Ajhauli, Deshi, Green, kasba, Dehradun and Dehra Rose are vigorus genotypes whereas Shahi, Rose Scented, Late Bedana, Trikolia and Purbi showed medium vigour. CHES-2, Bedana and China appeared to be dwarf stature genotype at adult bearing stage. With respect to yield, Shahi, Deshi and China have been found to be high yielding cultivars whereas Purbi, Ajhauli and Trikolia have been found as medium yielding genotype of litchi.

b. Based on cluster characteristics

Litchi has multi branched racemose inflorescence composed of several panicles in which fruits are generally borne in cluster. The cluster character and physical parameters of fruits (weight and volume) of litchi genotypes govern its production potential. The typical cluster characteristics of any litchi cultivar have a genetical base although, the external factors like climatic conditions and management practices also play a vital role. Keeping this in view, the characterization was done on the basis of flowering behavior and cluster characteristics of 17 litchi cultivars under sub humid plateau region of eastern India.

i. Sex ratio

Data on flowering behaviour of 17 litchi cultivars showed that the average number of flowers and male flowers at the top (780.2 and 655.2, respectively) was higher than that at the periphery (757.2 and 619.0, respectively). The maximum number of flowers was produced in cv. Green (1246.2) and the minimum in case of Swarna Roopa (285.2). The maximum number of female flowers (267.0) were recorded in cv. Kasba in the periphery followed by Ajhauli (198.0) and CHES-II (191.6).

ii. Fruit set and retention

The cultivars did not differ significantly with respect to initial fruit set, whereas the variation was highly significant with regard to number of fruits per cluster at maturity. Hence, it is evident that the percentage of fruit drop was very high in all the 17 cultivars which may be due to genotypic effect. The maximum number of fruits per cluster was recorded in cv. Late Bedana (14.9) which was at par with Purbi, Shahi and Bombaiya II. Cultivar Swarna Roopa recorded the minimum number of fruits per cluster (6.7). Cultivar Shahi recorded the minimum percent fruit drop (72.66) while it was the maximum in case of Bombaiya I (92.39).

iii. Cluster characteristics

Litchi has simple as well as compound bunch (more than one main axis). The different litchi cultivars differed significantly with respect to percent compound bunch which ranged from 0 in D’Rose to 100% in CHES-II, Bombaiya I and Swarna Roopa. Significantly higher correlation (0.73) was observed between percent compound bunch and per cent fruit drop. Significant differences were observed among different cultivars with respect to length of cluster which ranged from 15.0 cm in Swarna Roopa to 31.9 cm in Trikolia. The significant negative correlation between cluster length and per cent fruit drop (-0.54) as observed in the present studies may be attributed to the fact that the longer panicle may have minimized the competition among the fruits per unit length. Significant negative correlation was also observed between cluster length and per cent compound bunch (-0.49) and it may be due to the loss of apical dominance in the main axis of the inflorescence. The cultivars also differed significantly with respect to cluster width which ranged from 5.5 cm in Swarna Roopa to 12.0 cm in Late Bedana.

c. Characterization based on fruit characters

Cultivar synonymy does exist due to the insufficient information on characterization for different fruit morphological traits and delineation of the characters in its original name. Based on fruit characters and maturity period only few cultivars can be distinguished, which creates confusion in identifying the suitable cultivar for any specific region. Keeping this in view, the characterization was carried for 17 litchi genotypes on the basis of physico-chemical characteristics of fruit descried by IPGRI Descriptor.

i. Fruit physical parameters

Fruit length in different genotype of litchi varied from 2.77 (Swarna Roopa) to 3.67 (Bombaiya-II). The fruit length in cultivar Deshi, Kasba, Bombaiya-II, Bombaiya-I, Late Bedana, Green, Rose Scented, CHES-II and China were significantly higher than the other varieties. Fruit width was the maximum in cultivar Bedana (3.4 cm) followed by Bombaiya-I (3.25 cm) while the minimum values (2.52 cm) were recorded in cultivar Dehradun. Bedana and Bombaiya-I showed significantly higher fruit width among the litchi genotype. With respect to fruit shape index, maximum values (1.2) have been observed in cultivar China followed by 1.19 in cultivar Purbi and 1.17 in Bombaiya-II, which indicates an elongated fruit shape. Cultivar Bedana recorded the minimum value (0.9) followed by Swarna Roopa (0.95), Trikolia (1.00), Shahi (1.01) which can be anticipated with the roundish shape of the fruit. Fruit weight among the litchi cultivars varied from 14.34 (Trikolia) to 20.34 (Bombaiya-I). The cultivars Kasba, Bombaiya-II, Green, Rose Scented, Bedana and Shahi have shown significantly higher fruit weight in comparison to other cultivars under study. The pulp percentage in the fruit ranged from 53.84 to 77.09 being significantly higher in Bedana, D’Rose, Late Bedana, Green, and Rose Scented. Significant difference was observed among the cultivars with regard to peel weight which ranged from 1.42 (D’Rose) to 3.50 (Purbi) while the peel percentage ranged from 8.88 to (D’Rose) to 21.97 (Trikolia). The peel thickness was significantly higher in Purbi, China, Swarna Roopa and Dehradun while Green, D’Rose and Rose Scented had the thinnest peel. Skin protuberances has been used as a major key for classifying litchi genotypes. The genotypes differed significantly with regard to number of protruberances/cm2 which ranged from 10.25 (Swarna Roopa and Dehradun) to 15.50 (Ajhauli and Shahi).

ii. Quality parameters:

All the cultivars differed significantly with respect to their fruit quality. The percentage of total soluble solid was significantly higher in Purbi followed by Late Bedana, D’Rose, Kasba, and Rose Scented. However, the minimum percentage of TSS was recorded in Bombaiya-II (17.2). The total sugar percentage was the maximum in D’Rose (16.80) which was at par with Kasba and China. With regard to titratable acidity, it was the maximum in Dehradun (0.75%) and the minimum in CHES-II (0.28%). Cultivar Dehradun had the maximum ascorbic acid content (71.47 mg/ 100 g), while it was the minimum in Bedana (12.94 mg/ 100 g).

iii. Seed characteristics:

In order to facilitate the description of seed, different seed shape indices were hypothesized e.g. Seed Shape Index (SSI) and flatness of seed. Significant variation was observed among the cultivars with regard to seed shape index which ranged from 1.2 (Bedana) to 2.0 (Bombaiya-II). A high SSI is an indication of slender seed which was observed in cultivars Bombaiya-I, Bombaiya-II, Late Bedana, CHES-II, China and Purbi. Though the length of seed in cultivars Late Bedana was significantly lower, the lower width of the seed puts in under the category of slender seed. Similarly, the cultivars differed significantly with respect to flatness of seed. In the present study the flatness was higher in case of cultivars Deshi, Bombaiya-I and Late Bedana indicating flat seed. A lower value of flatness was observed in case of Trikolia, Dehradun, Swarna Roopa, Purbi, Ajhauli, Bedana, CHES-II, Rose Scented, Green, Bombaiya-II, D’Rose and Kasba indicating a cylindrical seed.

d. Characterization based on Growing Degree Days requirement

Growing Degree Days (GDD) is one of the easier and feasible method being used in different fruit crops for predicting fruit maturity. An experiment was conducted to find out the GDD requirement for litchi cultivars and test their validity with the existing method used for prediction of maturity. GDD values were determined using monthly maximum and minimum temperatures considering a base line temperature of 100C indicates the date of fruit setting and ripening of fruit cultivars during the period of experimentation. The maximum GDD was received during 1999 (1902.70C). Among the cultivars, it ranged from 1258.60C (Trikolia) to 1661.60C (Dehradun). The mean TSS : Acid ratio was the maximum during 1999 (71.2). Among the cultivars the TSS : Acid ratio ranged from 53.3 (China) to 79.9 (Rose Scented). Regression analysis indicated linear relationship between GDD and TSS : Acid ratio in 8 cultivars (R2 > 0.50) viz., Ajhauli, Green, China, Deshi, Dehradun, Kasba, Dehra Rose, Shahi. Based on this, the cultivars have been classified into different groups viz., GDD < 14000C (8 cultivars), 1400-16000C (3) > 16000 C (2), TSS : Acid ratio < 60 (3), 60-70 (5) > 70 (5).

Grouping of litchi cultivars based on Growing Degree Days requirement for maturity and fruit quality

DegreeDaysRange (0C) / Cultivar / TSS : Acid ratio range / Cultivar
< 1400 / Ajhauli, Trikolia, Shahi, Green, Early Bedana, Deshi, Dehra Rose, Rose Scented / < 60 / Green, China, Deshi
1400-1600 / China, Purbi, Late Bedana / 60-70 / Ajhauli, Late Bedana, Dehradun, Shahi, Trikolia
> 1600 / Dehradun, Kasba / > 70 / Purbi, Early Bedana, Kasba, Dehra Rose, Rose Scented

e. Differentiation of litchi genotypes based on leaf biochemical parameters

A study was undertaken with the objective to differentiate the litchi genotypes statistically, based on content of different biochemical constituents. Leaf samples collected from 25 genotypes of 25 year old litchi trees at 2 stages from fruit set to maturity were analyzed for content of Total free amino acid, total soluble protein, total phenol and total carbohydrate. At both the stages of observation, significant differences among the genotypes could be recorded for all the four parameters. During both the stage of observation, the content of total free amino acids was found to be the maximum in genotype Purbi whereas the genotype CHL-3 contained the maximum leaf carbohydrate content at both the stages of observation. Cluster analysis based on Euclidean Distance coefficients resulted in grouping the entire genotypes in to 5 primary clusters. Although the phenotypically similar genotypes were present in the first cluster, a number of phenotypically distinct genotypes were also found under the same cluster. The genotypes Shahi and China which are distinct from each other in terms of morphological as well as phenological characters, were found to have close affinity. However, the cultivar Swarna Roopa which is phenotypically distinct from other genotypes was found as single member in a different cluster. Hence, classification of genotypes through D2-analysis based on leaf biochemical characters like total free amino acid, total phenol, total soluble protein and total carbohydrate was found to be insufficient, although the method holds promise by inclusion of more number of biochemical parameters.