Genetic divergence among common bean cultivars from different races based on RAPD markers

The genetic divergence of 27 common bean (Phaseolus vulgaris L.) cultivars from different races was evaluated using RAPD markers. The association of t his divergence with some indirect variability estimates obtained in field e xperiments was also assessed. Genetic distances were calculated using Soren sen-Dice's similarity coefficient, displayed in a dendrogram (UPGMA method) , and by projection in two-dimensional space. Analysis of molecular varianc e (AMOVA) was used to evaluate the distribution of variance between and wit hin domestication centers. RAPD marker genetic diversity within these cente rs was also calculated. The correlations between estimates of genetic dista nces obtained with RAPD markers and estimates of Mahalanobis' generalized d istances, specific combination ability, and midparent heterosis obtained fr om morpho-agronomical traits were also determined. RAPD markers were effici ent in separating cultivars according to domestication centers. However, on ly for Middle American domestication center was there good agreement betwee n the grouping obtained and the proposed classification of races. The genet ic divergence obtained with these markers was similar to that provided by m orpho-agronomical traits. RAPD markers, however, were not efficient in pred icting the specific combination ability and midparent heterosis expressed i n crosses.