GENETIC DIVERGENCE AND CLUSTER ANALYSIS IN TOMATO ( Solanum lycopersicum

Present investigation was carried out at AICRP on Vegetable Crops, OUAT, Bhubaneswar, Odisha to assess the value and magnitude of genetic divergence among the genotypes using Mahalanobis D 2 statistics. About fifty five genotypes were evaluated for 17 growth, yield and quality traits which were grouped into nineteen clusters. Cluster V topped in having maximum of 11 genotypes

Present investigation was carried out at AICRP on Vegetable Crops, OUAT, Bhubaneswar, Odisha to assess the value and magnitude of genetic divergence among the genotypes using Mahalanobis D 2 statistics. About fifty five genotypes were evaluated for 17 growth, yield and quality traits which were grouped into nineteen clusters. Cluster V topped in having maximum of 11 genotypes followed by cluster I with nine and cluster XVIII with three genotypes while cluster II, III, IV, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII and XIX were monotypic. The maximum inter-cluster distance was noticed between cluster XIII and XVIII (D 2 =15603.23) followed by cluster XI and cluster XVIII (D 2 =13232.33). Therefore, selection of divergent parents of tomato based on these cluster distances would be useful in formulating a comprehensive strategy to develop superior hybrids or better segregants in tomato. On the basis of the present study, superior hybrids or variety (s) may be expected by crossing parents selected from cluster XIII (BT-19-1-1-1 X BT-22-4-1, BT-22-4-1 ) with parents of cluster XVIII (Utkal Kumari X BT-19-1-1-1, Utkal Kumari X BT-317, Utkal Kumari X BT-3).

…………………………………………………………………………………………………….... Introduction:-
Tomato (Solanum lycopersicum L.) is one of the important vegetable grown throughout the world. The cultivated tomato originated in a wild form in the Peru-Ecuador-Bolvia area of the Andes (Vavilov, 1951). Despite its wide cultivation and high yield potential the average yield is very low due to non-availability of improved varieties or hybrids. Diversity in parents is a pre-requisite in the development of variety or hybrid. Systematic study and evaluation of germplasm is of great importance for future genetic improvement of the crop. Furthermore, evaluation of germplasm is imperative, in order to understand the genetic background and breeding value of the available germplasm (Singh et al., 2002). Success of crop improvement programme depends on the extent of variability, choice of parents for hybridization and selection procedure. Multivariate analysis is a potent tool for measuring ISSN: 2320-5407 Int. J. Adv. Res. 6(4), 690-696 691 divergence among a set of populations based on multiple characters. D 2 statistic proposed by Mahalanobis (1936) has been generally used as an efficient tool in the quantitative estimation of genetic diversity for a breeding programme. For the first time use of this technique for assessing the genetic variability in plants was suggested by Rao (1952). Moreover, grouping of different genotypes of a particular crop by adopting Tocher's method will be more useful in choosing suitable parents for heterosis breeding. Keeping in view the above facts present investigation was undertaken with an objective to study of genetic diversity in fifty five genotypes of tomato based on seventeen important traits, to help in selecting promising and genetically diverse parents for desired improvement.

Materials and Methods:-
The experimental materials for the present study consisted of 55 genotypes of tomato evaluated at AICRP on Vegetable Crops, Orissa University of Agriculture and Technology, Bhubaneswar, Odisha during Rabi, 2016. The experiment was laid out in the randomized block design with three replications at spacing of 60cm x 45cm. The crop was raised by adopting recommended package of practices uniformly. Observations were recorded from five randomly selected plants (excluding border rows) of each genotype in each replication, for seventeen characters. Mean values of five plants were used for statistical analysis. The data of 55 genotypes of tomato were analyzed utilizing multivariate analysis (D 2 statistic) (Mahalanobis, 1936). The original measurements were transformed to standardized uncorrelated variables by pivotal condensation.Grouping of genotypes into different clusters was carried out by adopting Tocher's method and the relative contribution of different characters towards total divergence was calculated (Singh and Choudhary, 1985).  Utkal Kumari X BT-21, BT-19-1-1-1 X BT-317

Results and Discussion:-
On the basis of Mahalanobis D 2 analysis, 55 genotypes were grouped into 19 clusters (Table 1). Cluster V, the largest group included 11 genotypes followed by cluster I comprising of 9 genotypes and cluster XVIII comprising of 3 genotypes. Cluster II, III, IV, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII and XIX comprised of 02 genotypes each. When the clusters were compared for divergence, maximum inter-cluster distance was observed between clusters XIII and XVIII followed by XI and XVIII, clusters XII and XVIII, clusters XI and XVIII ( Table 2). The genotypes with BT as prefix were developed at AICRP on Vegetable Crops, OUAT, Bhubaneswar. But all such genotypes were distributed among divergent clusters. This indicated that geographic distribution and genetic divergence did not follow the same trend.
If genotypes possessing high genetic divergence are involved in hybridization programmes, it is expected that more heterotic hybrids and transgressive segregants may be produced in segregating generations. Present results are in agreement with the findings of Mahesh et al. (2006) and Singh et al. (2008).It is evident from Table 2 that cluster II had the minimum intra-cluster distance (6.17) whereas maximum intra-cluster distance (66.44) was observed in cluster XIX.
Since improvement in yield and other related traits is a basic objective in any breeding programme, cluster means for fruit yield plant -1 and its major components need to be considered for selection of parents. The cluster means of 17 quantitative and qualitative characters for groups of tomato genotypes are presented in Table 3 The relative contribution of 17 quantitative and qualitative traits to genetic divergence among the 55 genotypes of tomato have been presented in Table 4, by rank average of individual character over all 1485 paired combinations. Among the yield contributing quantitative characters, the maximum contribution towards divergence was made by yield plant -1 (32.3906) followed by average fruit weight (1.2121 %), length of fruits (0.1347 %), plant height (0.0673), total number of branches plant -1 (0.0673), number of fruits plant -1 (0.0673) and number of cluster plant -1 (0.0673). Rest of the qualitative characters contributing to divergence in descending order were ascorbic acid content (53.1313), acidity content of fruit (6.7340) and TSS of fruit (6.1279). It was observed that in the characters days to first flowering, days to 50% flowering, number of flowers cluster -1 , number of fruits cluster -1 , diameter of fruits, pericarp thickness of fruits and number of locules fruit -1 contribution to divergence was 0%. The characters like average fruit weight and number of fruits plant -1 will offer a good scope for improvement throughselection and directselection can be adopted effectively for achievingdesirable results. In order