554 Mapping of QTL for Seed Size and Shape Traits in Common Bean

Abstract

Our objective was to identify QTL for seed weight (SW), length, and height segregating in a recombinant inbred line (RIL) population from the cross `PC-50' (Larger SW) × XAN-159 (Smaller SW). The parents and RILs were grown in two separate greenhouse experiments in Nebraska, and in field plots in the Dominican Republic and Wisconsin. Data analysis was done for individual environments separately and on the mean over all environments. A simple linear regression analysis of all data indicated that most QTL appeared to be detected in the mean environment. Composite interval mapping (CIM) analysis was then applied to the means over environments. Eight QTL for SW were detected on common bean linkage groups (LGs) 3, 4, 5, 6, 7, and 8. All eight markers associated with these QTL were significant in a multiple regression analysis (MRA), where the full model explained 63% of the variation among SW means. Six QTL for seed length were detected on LGs 2, 3, 4, 8, and 11 using CIM. The markers associated with the three seed length QTL on LGs 2, 8, and 11 were significant in a MRA with the full model explaining 48% of the variation among seed length means. Three QTL for seed height on LGs 4, 6, and 11 explained 36% of the phenotypic variation for trait means. Four of the six QTL for seed length and two of three QTL for seed height also appeared to correspond to QTL for SW.