Selection potential for seed yield from intra- and inter-racial populations in common bean

Common bean populations from crosses between lines of different races are t hought to be more promising for selection of high yield potential than thos e from intra-racial crosses. Three distinct diallel crosses were made to te st this hypothesis and to determine the possibility of substituting diallel crosses for multivariate techniques that estimate genetic divergence. The crosses were between races Mesoamerica x Mesoamerica, Mesoamerica x Durango and Jalisco, and Mesoamerica x Nueva Granada. The parents and the resultin g F-4 populations were evaluated at Lavras-MG, Lambari-MG and Patos de Mina s-MG, Brazil. The diallel analysis of seed yield was done and the genetic d ivergence estimated by Mahalanobis distance. Estimates of general and speci fic combining ability indicated that some inter-racial populations were mor e promising for selection to increase seed yield than intra-racial populati ons. However, due to their undesirable seed color and size, and growth habi t, especially in a short term breeding program, the chances of obtaining hi gh yielding lines with an acceptable bean is reduced. Genetic divergence wa s not a good measure to choose the parents because usually, the most diverg ent groups included were not adapted lines.