摘要：

Forty genotypes of Indian mustard were evaluated during the rabi season of 2001-02 for days to 50% flowering and maturity, plant height, length of main branch, primary and secondary branches per plant, siliquae per plant, seeds per siliqua, length of siliqua, seed yield per plant, 1000-seed weight, oil content and harvest index. The analysis of variance showed highly significant differences among the genotypes for all the characters. The 40 strains were grouped into 4 clusters. Cluster I was the largest, consisting of 28 strains, while group IV comprised only one strain, suggesting that genotype Zem 2 diverged most from others. The intra-cluster distance was maximum in cluster II (102.7) and minimum in cluster IV (0.00), therefore, the 8 strains in cluster II indicated to be the most heterogeneous. As regards inter-cluster distance, the maximum statistical distance appeared between cluster III and cluster IV (594.1) followed by cluster I and cluster IV (415.5), suggesting wide diversity between them. An examination of cluster mean value showed that the importance of cluster IV for number of primary and secondary branches per plant, number of siliquae per plant, seeds per siliqua and seed yield and that of cluster III for early flowering, dwarf plant type, high oil content and high harvest index became obvious. The crosses involving parents belonging to the most divergent clusters are expected to manifest maximum heterosis. The clusters comprising only one genotype with specific traits could also be used in hybridization programme. Thus, the crosses between the genotypes of cluster III (SKM, TM 24 and TM 9) with that of cluster IV (Zem 2) would produce high heterosis and is also likely to exhibit new recombination with desired traits..

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