A Good Day to Flower: Environmental Dependent Genetic Control of Flowering Time in Common Bean

Common bean is the most important grain legume for direct consumption in human diets supplying necessary protein, carbohydrates, folic acid and micronutrients to more than 300 million people. Their wide range of cultivation in several continents makes it necessary to develop high yielding varieties adapted for various climatic zones throughout the world. The developmental transition (flowering time) from vegetative to reproductive stage plays a vital role in plants adaptability to a given environment. Local climatic cues as well as genetically controlled signal transduction pathways dictate the timing of anthesis. Therefore, genetic manipulation can help us tailor the timing of flowering to develop cultivars adapted to specific climatic zones. This study aimed to locate major genes (G) and environmental (E) factors controlling flowering time in common bean, and to identify and measure G x E interactions. Flowering time phenotype data were collected from a biparental [Andean x Mesoamerican] recombinant inbred population (F_11:14, 188 genotypes) grown at five environmentally distinct sites. A dense linkage map with 513 markers (1.8 cM inter-marker distance) was constructed using the genotyping-by-sequencing technology. QTL analysis revealed eleven QTL, and four of these showed strong interaction with the environment. G x E interaction was dissected using linear mixed models, which revealed that temperature, photoperiod and solar radiation interacted with specific QTL thereby playing major role in controlling flowering time.