RESISTANCE OF BEAN (Phaseolus vulgaris L.) IMPROVED THROUGH QUANTITATIVE METHODS AGAINST Xanthomonas axonopodis pv. phaseoli

Abstract

A genetic improvement program was developed for global horizontal resistance in bean (Phaseolus vulgaris L.), with an emphasis on common blight (Xanthomonas axonopodis pv. phaseoli), for the Mixtec region in Oaxaca, México. Laboratory and field experiments were performed in the summer and autumn seasons of 2002, to evaluate the level of resistance accumulated in the genotypes of improvement cycles 3, 4, 5, 6 and 7, comparing them with the levels of resistance of the original parents, and regional and commercial varieties. Through the application of severe pressure from the bacteria inoculum, the greatest genetic advancement against X. axonopodis pv. phaseoli was made evident, in the genotypes of the most advanced cycles, considering the yield, incidence and reduced damage of the bacteria, both in
laboratory and field experiments.