An assessment of genetic diversity and combining ability of elite castor genotypes suitable for rainfed conditions

Abstract

A study was conducted to assess the diversity of 72 castor genotypes used as male lines in the hybrid breeding programme in India using multivariate analysis in addition to morphological characterization using DUS (Distinctiveness, Uniformity and Stability) testing guidelines of castor. Fifteen agronomical and three morphological traits were measured in 72 genotypes in field studies conducted for two years. The multivariate data set was subjected to genetic divergence analysis using Mahalonobis’ D2 static and clustered into nine subgroups following Tocher’s method in addition to Principal Component Analysis (PCA). The genotypes from Clusters 1 and 5 and Clusters 2 and 5 are genetically diverse with 556.9 and 469.7 units while cluster 7 genotypes with higher mean seed yield are potential candidates as varieties after multilocation testing. In PCA, the first two canonical variants were significant and accounted for 68 per cent of the inter accession variability. Grouping of castor genotypes was also done based on four grouping characteristics of DUS guidelines like stem color, bloom, capsule spines and maturity. Combining ability analysis indicated that DCS-96, DCS-94, DCS-104, DCS-97 were good general combiners for seed yield while M-568 x DCS-96 yielded 21 per cent standard heterosis over the best check DCH-177.