Multivariate analysis of genetic divergence and selection indices for yield enhancement in soybean [Glycine max (L.) Merril]

Abstract

In the present study, 45 soybean genotypes [Glycine max (L.) Merril] were evaluated for morphophysiological diversity through Mahalanobis D² statistics and selection indices. The experiment was executed at the Main Oilseeds Research Station, JAU, Junagadh during Kharif-2024 using a Randomized Block Design with three replications and data were collected on 14 quantitative traits. The genotypes of soybean were grouped into 11 clusters from 45 genotypes. The cluster IV was the largest with 14 genotypes followed by cluster I which contained 12 and cluster V which have 11 genotypes. The remaining cluster i.e. cluster II, III, VI, VII, VIII, IX, X and XI are solitary cluster. The maximum inter-cluster distance was found between clusters XI and X (D = 22.66) and intra-cluster distance maximum being in cluster V (D = 12.08). the expected genetic advance and relative efficiency assessed for different indices increased considerably when selection was based on two or more characters. seed yield per plant (X1) along with four components viz., number of pods per plant (X2), number of pods per cluster (X3), biological yield per plant (X4) and harvest index (X5) were identified and considered. Thirty-one selection indices were constructed in all possible combinations of the four yield contributing characters and seed yield per plant. relative efficiency of single character index was measured, it was noted that the maximum efficiency of (520.29%) was exhibited by harvest index, Among the combination involving two component characters; number of pods per plant and harvest index (X2+X5) exhibited maximum relative efficiency of 621.72%, The selection index based on three-character combinations indicated that a discriminant function with number of pods per plant, biological yield per plant and harvest index (X2+X4+X5) possessed maximum relative efficiency of 654.74%. In four-character selection index, a function involving seed yield per plant, number of pods per plant, biological yield per plant and harvest index (X1+X2+X4+X5) exerted maximum relative efficiency of 669.50%.