Identification of superior progenies between common bean gene groups for root system obtained by recurrent selection

Abstract

Genetic variability is essential for gains in breeding programs. The cyclic process of progeny recombination is a strategy to raise the chances of selecting better genotype combinations. The objective of this study was to identify superior progenies between common bean genes groups in first recurrent selection cycle for root system traits. Parents of the Andean and Middle American gene groups were hybridized in a complete diallel scheme. Thereafter, the parents and F 1 and F 2 populations were planted in the field. To establish the base population of recurrent selection (C 0 ), seven segregating populations (F 2 ) with superior performance for root system were selected and intercrossed, resulting in recombinant progenies (C 1 ). To estimate the selection gain, the parents and C 0 and C 1 genotypes were compared with regard to the following variables: total root length (TRL, cm), projected root area (PRA, cm²), root volume (VOL, cm³) and number of root tips (RT). The difference between genotype combinations indicates the presence of genetic variability and effectiveness of recurrent selection. The mean genetic progress for root system-related traits was 12.9% (TRL), 12.6% (PRA), 12% (VOL) and 11.5% (RT) in the first recombination cycle. The mean phenotypic performance of seven of the C 1 progenies exceeded that of their parents for all root system traits. These progenies are promising as base populations of the next selection cycle.