Research Article Recurrent selection to obtain drought-tolerant common bean progenies

Abstract

Common bean yield is directly related to climate conditions, and water deficit is one of the main limiting factors. One way of getting around this problem is increasing the frequency of alleles favorable to drought tolerance by the recurrent selection method. We estimated the morphophysiological and agronomic gains achieved in two recurrent selection cycles for drought tolerance and evaluated the genetic potential of the progenies obtained in each cycle. The first recurrent selection cycle was obtained by intercrossing 10 genotypes. This cycle was followed by physiological, morphophysiological, and agronomic evaluations, resulting in selection of 17 progenies. The second cycle was obtained by intercrossing the 17 selected progenies, followed by the same evaluations, resulting in 20 selected progenies. A randomized block experimental design was used for both selection cycles, with split plots and three replications. The plots consisted of two water treatments (irrigated and water deficit), and the subplots consisted of the progenies under evaluation. To select the progenies and estimate the genetic parameters, only the treatment under water deficit was considered, in randomized blocks with three replications. Irrigation was suspended at the R5 stage. Under these conditions, the following traits were evaluated: stomatal conductance, leaf temperature, relative