Detection of QTLs Controlling Time to First Anthesis in Phaseolus vulgaris L

Fine tuning the timing of transition from vegetative and reproductive stages to suit specific environments can significantly increase yields. This can be accomplished by identifying genes that control rates of development, particularly those that are responsive to environmental factors.  The aim of this study was to identify major QTL controlling time to first anthesis (TFA) in common beans. To reach our goal, we phenotyped a RIL population [Mesoamerican x Andean] comprised of 188 individuals for TFA at five different sites with contrasting temperatures and photoperiod regimes. To facilitate mapping process, we build a dense SNP-based linkage map (1.7cM) via the genotyping-by-sequencing approach. TFA (calendar days) and genotype data allowed us to map seven QTLs regulating time to TFA in our population, some of these were site specific. We further converted the calendar days to growing degree days (GDD) to normalize temperature effects on the rate of development. GDD-based QTL analysis allowed us to identify QTLs controlling developmental rates under an optimal growth environment, as well as QTLs that control developmental rates as a function of environmental factors.