Genetic divergence analysis in germplasm of Indian mustard (Brassica juncea L. Czern & Coss.).
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Date
2012
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CCSHAU
Abstract
An attempt was made to study the genetic divergence amongst 200 germplasm lines of Indian
mustard. Significant differences for various traits indicated substantial amount of variability existed
among the germplasm lines for various traits. High heritability coupled with high genetic advance was
observed for seed yield and most of the traits. Based on relative magnitude of genetic distances 200
germplasm lines were grouped into 10 clusters. The clusters I comprising 28 germplasm lines followed
by cluster II and III consosting of 26 germplasm lines, cluster IV, V, VI, VII, VIII,IX and X contained
22,21,21,21,15,11 and 9 germplasm lines, respectively. No correspondence was observed between the
geographical and the genetic diversity, but distribution of genotypes were random and independent.The
magnitude of inter-cluster distance was greater than intra-cluster diatances, suggesting presence of
diversity among the clusters. The maximum inter-cluster distance was observed cluster VI and VIII
(6.542) followed by cluster IX and X (6.447); cluster VIII and IX (6.420); cluster VIII and X (6.408);
cluster V and IX (6.394); cluster VII and VIII (6.376); cluster III and VIII (6.359); cluster II and VIII
(6.222) and cluster V and VIII (6.171).The use of germplasm lines in hybridization from these clusters
having most of the desirable characters are likely to produce more heterotic hybrids vis a vis
transgressive segregants. The D2 analysis indicated that high variation for various seed yield
contributing traits viz. number of secondary branches per plant, number of primary branches per plant,
siliqua angle, 1000 seed weight and speed of germination contributed more than 70% of the total
divergence and had maximum contribution towards genetic divergence. In general genotypic
correlation coefficient were higher in magnitude than theirphenotypic correlation coefficient.
Seed yield per plant was found to be positively and significantly correlated with plant height, number
of primary branches per plant, number of secondary branches per plant, main shoot length, and number
of siliquae on main shoot. Path analysis reveled that characters such as number of secondary
branches/plant, number of siliquae on main shoot,germination percentage and primary branches angle
were the major component traits of seed yield and hence these characters should be given priority in
selection in view of their high heritability coupled with high genetic advance also. The genotypes RC-
1001,RC-1004,RC-1007,RC-1008,RC-1200,RC-1017,RC-1021,RC-1118, RC-1070,RC-1149,RC-
1548,RC-1347selected from various divergent clustetrs having most of the desirable characters were
identified as promising on the basis of genetic divergence and per se performance for several traits
particularly for seed yield and oil content and can be used in future breeding programme for improving
seed yield and component traits in order to enhance the productivity of Indian mustard.
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Keywords
Brassica species, Indain mustard, Genetic divergence, Multivariate analysis