D2 analysis in Lathyrus (Lathyrus sativus L.) germplasm lines

Fifty-five genotypes were evaluated for a genetic divergence to identify potential parents for the lathyrus breeding program aimed at yield improvement. Mahalanobis D² statistics for eight characters viz. days to 50% flowering (on plot basis), days to maturity (on plot basis), plant height (cm), number of primary branches plant-1, number of seeds pod-1, number of pods plant-1, 100 seed weight (g) and yield plant-1 were used in this study for computing genetic divergence. The analysis of dispersion for eight characters using Wilk’s criterion revealed a highly significant difference between genotypes for all eight characters. The fifty-five genotypes were grouped into seven clusters by Tocher’s method. The maximum inter-cluster distance was recorded between cluster III and cluster VII (D2=15.40) and in between cluster V and cluster VII (D2 = 14.75) whereas the minimum inter-cluster distance was found between cluster IV and cluster VI (D²=3.56). The canonical analysis indicated that yield plant-1, 100 seed weight, number of pods plant-1, number of seeds pod-1, number of primary branches plant-1 and days to 50% flowering were significant source of variation in vector I. Characters number of seeds pod-1, number of pods plant-1, days to 50% flowering and plant height were important source of variation in vector II. Number of seeds pod-1, yield plant-1 and days to 50% flowering were important characters in vector III. The canonical analysis and cluster mean studied together revealed the importance of number of pods plant-1, yield plant-1, and number of seeds pod-1 as important contributors towards the total divergence. Hence, these traits form the criterion for the selection of parents for hybridization program. The 19 genotypes viz., EC-209071, NLK-39, IC-120491, NLK-37, NLK-56, NLK-6, NLK-40, NLK-49, NLK-38, NLK-54, NLK-73, EC-207071, NLK-42, NLK-74, BIOR-208, AKL-7, JRL-16, BIOR-231 and BIOR-222 were identified as potential and diverse parents for their use in crossing program.