Modeling the Genetic and Environmental Factors Underlying Post-Anthesis Reproductive Development in the Common Bean (Phaseolus vulgaris L.)

The common bean (Phaseolus vulgaris L.) is an important grain legume for direct human consumption. In spite of its importance, many key questions remain about its reproductive biology, including the environmental sensitivity and genetic control of post-anthesis reproductive development. The objective of this study was to study the genetic and environmental factors that affect post-anthesis reproductive development in the common bean. The study centered on a recombinant inbred (RIL) population developed from a cross between an Andean (‘Calima’) and a Mesoamerican (‘Jamapa’) cultivar. The population was grown in three contrasting sites in the USA (Florida, North Dakota and Puerto Rico) and two in Colombia (Palmira and Popayan), that varied widely in climatic conditions. Six plants of each genotype in each of 3-6 plots per site were monitored for the timing of the onset of reproductive stages after anthesis: first pod appearance (R3), onset of seed-fill (R5) and physiological maturity (R7). Over 12 quantitative trait loci (QTL) were detected that affect the timing and duration of post-anthesis reproductive stages in the RIL population using mixed-effects QTL models. These included two major QTLs, Fin and DiM.1-22, that affect the timing for the onset of stages R3 (first pod) through R7 (physiological maturity), and the duration of seed fill (R5-R7), respectively, explaining up to 34% of the observed phenotypic variance. Moreover, results from mixed-effects models that incorporate environmental covariates suggest that DiM.1-22  has temperature and photoperiod-specific effects.