Population bulk versus F1-derived family methods of yield testing in early generations of multiple-parent interracial and inter-gene-pool crosses of common bean

Abstract

To simultaneously improve qualitative and quantitative agronomic traits, markers and gamete selection can be used. However, the effectiveness of alternative methods of yield testing in early generations must first be investigated. In this study, we therefore determined the relationships between seed yield of F1-derived families and of population bulks in F2 and F3 generations. We also compared seed yields of a high-versus low-yielding population in F2 and F3 with their advanced generation (F7) lines. First, we yield-tested 25 multiple-parent, interracial and inter-gene-pool populations, each represented by their population bulk, and 24 F1-derived families, at three locations, in F2 (1993) and F3 (1994). Each plot of the bulk of each population consisted of four rows and was replicated twice. The 24 F1-derived families were randomly divided into six groups of four. The four families of each group were sown together to represent one plot of each replication. But each family was harvested separately and the mean yield of the four families represented the plot yield. Then, based on the mean seed yield of F2 and F3, one comparatively high-yielding and one low-yielding population were selected. Ten F4-derived F7 lines from each population were yield tested at the same three locations in 1995–1996. Positive correlations were found between the mean seed yields of F2 and F3, and between the seed yield of population bulks and the yields of F1-derived families in both F2 and F3. The mean seed yield of the 10 F4.7 lines from the high-yielding population was significantly higher (P < 0.05) than that of its counterpart from the low-yielding population. Marker-assisted gamete selection for qualitative traits during hybridization and population development in the F1 can therefore be combined with yield selection among F1-derived families in early generations of common bean populations. Key words: Common bean, Phaseolus vulgaris L., gamete selection, early generation yield testing