MIXING ABILITY AND INTERGENOTYPIC COMPETITION FROM 7X7 UNIBLENDS AND BIBLENDS OF MUNGBEAN (Vigna radiata L,Wilckzek.) GENOTYPES

Abstract

Cultivar mixtures have been suggested as a means to achieve increased crop productivity. By choosing cultivars that complement each other for performance of important traits, mixtures could be formulated to meet specific production requirements. Mixing ability and inter-genotypic competition from 7x7 mechanical diallel mixtures excluding reciprocals of Mungbean (Vigna radiata (1.) Wilczek.) were studied, during March to Mid June 2008, under two experimental sets which provided for intra-row and inter row mixing of genotypes in biblend, designated respectively as Set I and set II, as well as uniblend stand in both Sets. The significant differences among the genotypes were found for all the traits examined. Seven mungbean uniblend line and the 21 biblends obtained by mixing seed of pairs of cultivars in equal proportions were evaluated. The mean performance analysis showed that, the genotype BD-6893 showed best performance for most of the vitally important characters such as pods per plant, seeds/plant, and yield/plant. In respect of biblend mixture, the biblend BD-6901+BD-6922 was found as best biblend mixture for different characters. Averaged biblends were 1.35% higher yielding than the mean yield of their uniblend components. For grain yield, performance in biblends was highly correlated with the average of the two component uniblends. The genotype BD-6906 had a good mixing ability for different yield and yield contributing characters as pods/plant, pod length, seeds/pod, yield/plant etc. in the both experimental sets. The mixture (biblend) BD-6901 + BD-6922, BD-6893+BD-6901 and BD-6921+BD-6922 were found to be a good specific mixer for different characters. Diallel analysis of mixing ability, analogous to genetic analysis of combining ability, demonstrated that uniblends differed in their ability to determine grain yield in biblends. The ability to predict biblend performance based on uniblend performance, together with the potential for above average grain yield, suggested that biblends can be formulated to achieve specific production requirements. Although varietal mixtures are not an alternative to pure culture, they nevertheless exhibit better performance under any adverse conditio