Effect of random intermatings in early generations on seed yield in interracial populations of common bean

Abstract

Zero (I0), one (I1), and two (I2) rounds of random intermating were made among S1 or S0 families of two interracial populations (GX 8904 and GX 8929) of common bean (Phaseolus vulgaris L.). The resulting S4 families were evaluated for seed yield, 100-seed weight, and number of days to maturity in six environments in Colombia during 1993 and 1994. The experimental design was a partially balanced, 10 × 10 lattice, with three replications. The mean seed yield after I1 increased by 8.9% in population GX 8904 and by 20.1% in GX 8929. No change occurred in seed yield after I2 in either population. The I1 and I2 of GX 8904, on average, were slightly later maturing than the I0. In GX 8929, I2 was later maturing than I0 and I1. The random intermatings did not induce appreciable changes in 100-seed weight in either population. All S4 families in both populations were either small or medium seeded (< 40 g/100 seed weight) and of intermediate to late maturity (> 70 d to maturity). Key words: Bean (common), interracial population, Phaseolus vulgaris, random intermating, yield selection