Association Analysis, Genetic Variability and Genetic Diversity Studies in Soybean [Glycine max (L.) Merrill]

To study the genetic variability, association analysis and genetic diversity for productivity in soybean, a field experiment was conducted during Kharif 2005 at University of Agricultural Sciences, Dharwad, India. The experiment comprised of 84 genotypes of which, most of the cultivars were released in India, along with some indigenous and exotic lines. Observations on 11 productivity traits of soybean were recorded. The data were subjected to variability and multivariate analysis. The analysis of variance revealed the prevalence of significant difference among the genotypes for all the 11 characters studied. Plant height was the only character which showed high phenotypic and genotypic co-efficient of variation while days to maturity, number of nodes per plant and oil content recorded a low phenotypic and genotypic coefficient of variation and rest of characters recorded moderate phenotypic and genotypic coefficient of variation. Number of pods per plant, pod weight per plant, 100 seed weight and oil content showed positive and significant correlation with seed yield per plant. Path coefficient analysis revealed maximum positive direct effect of pod weight on seed yield per plant followed by 100 seed weight and its indirect effect through other characters were also considerably high. Therefore, emphasis may be laid on this character for improving seed yield. There was not much amount of diversity was obtained in the material representing diverse eco-geographical regions of the country revealed no relationship between geographic diversity and genetic diversity.