Combining ability of common bean in a complete diallel cross under water deficit

Abstract

The aim of this study was to identify drought-tolerant parents and combinations of common bean based on general and specific combining abilities. A complete diallel was conducted, including the reciprocals, among 12 parents, obtaining 132 populations.These populations and respective parents were evaluated in pots in a greenhouse in a randomized block experimental design with three replications and placed under intermittent water deficit applied in the pre-flowering. Physiological, morphological, and agronomic traits were evaluated, and general combining ability (GCA), specific combining ability (SCA), and reciprocal effect (RE) were estimated. Significant effects were found among the genotypes for most of the traits confirming genetic variability among populations. The additive effects were more expressive than the non-additive effects, with reciprocal effect for some traits. The Carioca Precoce and SER 16 parents exhibited significant GCA, contributing alleles favorable to additive effects for increasing grain yield and harvest index. Significance of SCA and RE was not observed for grain yield. However, the SEA 5 (pollen receptor) × SER 16, Carioca Precoce (pollen receptor) × BRS FP403, and the reciprocal Carioca Precoce (pollen donor) × BRS FP403 hybrid combinations achieved positive estimates for harvest index, which is an indirect selection trait for grain yield. This study allowed selection of progenies coming from the parents Carioca Precoce and SER 16, as manifested favorable traits related to grain yield.