MIXING ABILITY AND INTER.-GENOTYPIC COMPETITION FROM 7x7 UNIBLENDS AND BIBLENDS OF SOYBEAN GENOTYPES

Abstract

Mixing ability and inter-genotypic competition from 70 mechanical diallel mixtures excluding reciprocals of Soybean (Glycine mat L.) were studied, during November 2001-April 2002, under two experimental sets which provided for intra-row and interrow mixing of genotypes in biblend, designated respectively as Set I and Set 11, as well as uniblend stand in both. The significant differences among the genotypes were found for all the traits examined. The mean performance analysis showed that, the genotype PM-78 had earliness for flowering and maturity, and the biblends PM-fl + Ramsom and BS-3+ 85-16 exhibited earliest flowering and maturity behaviour. The genotype G-2 showed the best performance for pods/plant, seeds/plant, yield/plant, biological yield/plant, and yield/plot. Variances due to general mixing ability (GMA) and specific mixing ability (SMA) were significant for most of the traits. The predominant role of OMA variances were affirmed in all the characters studied. The genotype PM-iS was found to be the best general mixer for earliness in flowering and maturity in both experimental sets. The genotype BS-16 was found to be a good general mixer for plant height, branches/plant, yield/plant, biological yield/plant, and yield/plot in both the experimental sets. The genotype G-2 had a good mixing ability for pods/plant, seeds/S-pods and seeds/plant in the both experimental sets. Whilst the genotype BS-60 was found to be a good general mixer for harvest index in both experiments, as revealed by thcir respective uniblend stand. The mixture (biblend) BS-60 + 85-16 was earliest in flowering and maturity. The plant mixture BS-3+BS-16 was found to be a good specific mixer for plant height, branches/plant, pods/plant, seeds/plant, yield/plant, biological yield/plant, and yield/plot in experimental Set-I. But in experimental Set-Il, the mixture P13-l+BS-16 was found to be a good mixer for branches/plant, pods/plant, seeds/S-pods, seeds/plant, yield/plant, biological yield/plant, yield/plot and 100-seed weight. For experimental Set I, the biblend BS-3+BS-16 and for experimental Set lithe biblend PB-I +BS-1 6 were the best specific mixers.