Selection index for recommendation of cowpea cultivars for green bean production

Abstract

Cowpea is one of the main food crops in the Northeast region of Brazil, thus, breeders have carried out researches to identify genotypes with good production response and attributes that satisfy growers and consumer market demands for green beans and pods. Therefore, the objective of this work was to develop a selection index that assists in the recommendation of cowpea cultivars for green bean production and select the best genotypes based on this index. Twenty cowpea genotypes, including lines and cultivars, were evaluated for eleven characters in five locations in the state of Ceará, Brazil: Acaraú, Pentecoste, Crato, Mauriti, and Madalena. A randomized block design was used, with four replications. The characters evaluated were: number of days for the beginning of flowering (NDF), number of days for maturation (NDM), plant height (PH), green pod length (GPL), number of beans per green pod (NBP), green pod weight (GPW), bean weight per green pod (BWP), one hundred green bean weight (100GBW), bean index (BI), green pod yield (GPY), and green bean yield (GBY). The results of the characters were subjected to analysis of relative importance, estimated by principal component analysis and analysis of factors, and used to develop selection indexes. The following index was obtained: I 3 = 0.079 NDF -0.083 PH + 0.119 GPL + 0.034 GPW -0.176 100GBW + 0.340 GPY. This index indicated that the genotypes MNC05-847B-123, Azulão-MS, MNC00-595F-27, MNC99-541F-15, MNC05-835B-16, and MNC00-595F-2 are the most promising for green bean production.