Selection for seed yield in Middle American versus Andean × Middle American interracial common‐bean populations

Abstract

The objective of this study was to compare the seed yield, seed weight, and maturity of random lines derived from two contrasting populations of common bean (Phaseolus vulgaris L.): Middle American (TR 7790) and Andean × Middle American (TR 7791). TR 7790 involved crosses between common‐bean races of Middle American origin only (Mesoamerica and Durango), whereas TR 7791 involved crosses between races of Middle American and Andean origin (Mesoamerica and Nueva Granada). A total of 85 random lines from each of these two double‐cross, interracial populations, a bulk sample of both populations, and all parents were evaluated in a replications‐in‐set design in eight environments in Colombia between 1991 and 1993. The mean yields of parents, population bulk, and lines from TR 7790 were significantly higher (P < 0.05) than those of TR 7791. Six lines in TR 7790 and nine lines in TR 7791 yielded significantly higher (P < 0.05) than the mean of their parents. Four lines from TR 7790 out‐yielded the highest‐yielding line from TR 7791. Moreover, while three lines from TR 7790 out‐yielded its best parent, none of the lines from TR 7791 out‐yielded its highest yielding parent. Thus, substantial yield gains should be expected from interracial populations within the Middle American group of common beans, whereas selection for higher seed yield from Andean × Middle American populations would seem problematic.