Influence of cropping systems on combining ability and gene action for grain yield and its components in blackgram (Vigna mungo)

Field experiments were conducted at Regional Research Station, Himachal Pradesh Agricultural University, Palampur during rainy (kharif) season of 2003-04 and 2004-05 to study the effect of cropping system on the nature and magnitude of gene action for seed yield and its component traits in the parents and progenies of linextester cross in blackgram [Vigna mungo (L.) Hepper], grown both as a sole crop and intercrop with maize (Zea mays L.). There was not much effect of cropping system in the manifestation of phenotypic and genotypic variability. There were strong progeniesxcropping system interactions for different traits. Cropping system had a large influence on the phenotypic expression of yield and its components. Both additive (sigma 2A) and non-additive (sigma 2D) genetic variances were important in the genetic determination of seed yield and its components. However, the ratio of sigma(2)A to sigma(2)D was greater under monoculture than under intercropping for almost all the traits except harvest index, seeds/pod, pods/plant and days to 50% flowering, where it increased indicating that cropping systems influence the genetic control of important yield component traits. However, the occurrence of low genotypic correlations for seed yield and its components across and cropping systems justify the selection of different parents and crosses for monoculture and in association with blackgram.