Marker‐Assisted Selection to Improve Drought Resistance in Common Bean

Abstract

Breeding for a quantitative trait like drought resistance would be facilitated by the development of a method of marker‐assisted selection (MAS) that is capable of identifying high performing genotypes in early generations. Two recombinant inbred populations were grown from 1990 to 1994 at eight locations in Michigan and Mexico under stress and nonstress conditions to identify random amplified polymorphic DNA (RAPD) markers associated with drought resistance in common bean (Phaseolus vulgaris L.) Six‐hundred random decamer primers were screened against the parents of the two populations, 50% of which were polymorphic. Seventy of these polymorphic primers were screened against each population. Using one‐way analysis of variance and multiple regression, four RAPD markers were identified in one population and five in another that were consistently and significantly associated with yield under stress, yield under nonstress, and/or geometric mean yield across a broad range of environments. To test the effectiveness of MAS for drought resistance, markers were used to select genotypes from either extreme. Yield data from three locations were examined to evaluate the effectiveness of these markerbased selections. Marker‐assisted selection in the Sierra/AC1028 population was found to be effective in Michigan under severe stress and ineffective in Mexico under moderate stress. The five RAPD markers used for MAS in the Sierra/Lef‐2RB population improved performance 11% under stress and 8% under nonstress, whereas conventional selection based on yield performance failed to increase performance. Response to conventional selection was three times greater in the Sierra/AC1028 population, supporting the conclusion that the effectiveness of MAS is inversely proportional to the heritability of the trait under examination.