Efficiency of progeny selection in common bean for oxalic acid reaction

Abstract

The common bean is affected by several diseases like white mold (Sclerotinia sclerotiorum), that reduces the grain quality and grain yield in many countries, mainly in culture under mild temperature and high humidity. Genetic resistance is one of the measure that contribute for diminish these problems, although higher level of resistance are not still available in most of the cultivars. Some resistance sources are promising although in general they are not adapted especially in the growing conditions of Brazil. There are several procedures for evaluating white mold resistance in common bean, and an indirect one is through measuring the ability of young plants to support the oxalic acid solution for some hours, expressed by the level of wilting of the plants (Kolkman & Kelly, 2000). This acid is exuded by the fungus during the plant infection process, and those that tolerate this acid are considered more resistant.This indirect method of measuring the resistance is fast, easy, many plants can be evaluated at a time, and also it is free of the error, which is caused by the variability of the pathogen in the direct evaluation of the resistance. However, due to the quantitative nature of the white mold resistance, it is important to use an efficient procedure of selection like evaluate progeny instead of individual plant. Thus the objective was to check the efficiency of evaluating common bean progenies reaction to oxalic acid compared to individual plants.