Two Cycles of Recurrent Selection for Seed Yield in Common Bean

Abstract

Seed yield of common bean (Phaseolus vulgaris L.) can be improved by exploiting the genetic variability available in the crop's cultivated races and gene pools. The objectives of this study were to (i) compare yield gains obtained through two cycles of recurrent selection, based on S1 family tests, in two types of populations [interracial Middle American (MA) and inter‐gene‐pool Andean × Middle American (AMA)], and (ii) estimate genetic variance, heritability, and expected gains from selection. The MA population comprised 11 parents from race Mesoamerica, three from Jalisco (Mexico), and two from Durango (Mexico). The AMA population had six parents from race Mesoamerica, one from Jalisco, five from Nueva Granada (northern Andes), and two from Chile (also Andean). From the initial cycle (C0,) of each population, 45 S2 families were evaluated at three locations in Colombia in 1992 to select the 10 highest yielding families to be intermated in a diallel fashion (excluding reciprocals) to generate 45 S1 families for cycle 1 (C1). Similarly, 45 S1 families from C1 and cycle 2 (C2) were evaluated in 1993 and 1995, respectively. The 10 highest yielding selected families from each of C0, C1, and C2 and a corresponding bulk of all 45 S1 families from each of the three cycles were evaluated at three sites in 1997. Data were recorded for seed yield, seed weight, and maturity. Genetic variance among 45 S1 families in C1 and C2 was greater in the AMA population than in the MA, diminishing from C1 to C2 in MA and increasing in AMA. Heritability for seed yield ranged from 0.31 to 0.46, for seed weight from 0.75 to 0.86, and for maturity from 0.50 to 0.81. Expected gains from selection for seed yield was lower (3–4%) in C2 compared with C1 (7.9–13.2.%). The mean yields of C0, C1, and C2 of the MA were significantly (P < 0.05) higher than those of the AMA. The C2 of both MA and AMA out yielded their respective C1 and Co families. The average realized yield gain per selection cycle was 15% or higher in both populations. These results justify the use of recurrent selection in interracial and inter‐gene‐pool populations for improving seed yield of common bean.