Genetic variability, character association and genetic divergence in soybean [Glycine max (L.) merrill] germplasm under rainfed situation of Assam

Genetic variability, character association and genetic divergence was studied in a set of 44 soybean germplasm with respect to 10 quantitative traits viz. Plant height (PH), Internodal length(IL), No. of trifoliate leaves plant⁻¹ (TL), Pods plant⁻¹ (PP), Seeds plant⁻¹ (SP), 100-seed weight (SW), Pod weight (PW), Seed yield plant⁻¹ (SY), Days to 50% flowering (DF) and Days to maturity (DM). Highest Genotypic as well as phenotypic coefficient of variance (GCV and PCV) were observed for 100-seed weight followed by seed yield plant⁻¹ and seeds plant⁻¹ revealing a high level of diversity among the genotypes for these traits. Character association studies revealed significant and positive genetic correlation of seed yield plant⁻¹ with pod weight plant⁻¹ and 100-Seed weight. This indicated that selection for these traits would be effective for improving seed yield plant⁻¹. All the native soybean germplasm of North East India except for one variety (NESC 6) belonging to the same cluster indicated their close relationship. The diversity study revealed no significant relationship between gentetic diversity and geographical distribution of soybean genotypes. Based on the genetic distance, character association and the per se performance of the genotypes, crossing programme may be undertaken considering the parents viz. NESC 10(For seed yield), VLS 81(For seed weight), KS 112(For seeds plant⁻¹) and JS 20–35 (For pods plant⁻¹) belonging to clusters, VII, I and III, respectively for improving seed yield in soybean.