Advances in the Breeding and Genetics of Heat Tolerance to Alleviate the Effects of Climate Change, with a Focus on Common Bean

Crop plants are broadly sensitive to high ambient temperatures during reproductive development while breeding efforts are helping to alleviate the impact of heat stress. Common bean, Phaseolus vulgaris L., is sensitive to moderately high ambient temperature, where temperatures greater than 25C have adverse effects on reproductive development. Some marginal production areas have already reached these temperatures, while climate change will increase the proportion of the production area under heat stress. Simulations indicate that in some common bean producing countries, increasing temperatures will reduce seed yield by 2030. Field experiments under high ambient temperatures are effective for selection of heat tolerance, and reveal sensitivity to heat during male reproductive development, including the response of pollen shed and pollen viability. The progress in elucidating the genetics of response to high ambient temperature stress using genotyping-by-sequencing and association mapping analysis will be presented. Significant advances in developing heat tolerant dry bean and snap bean cultivars have been achieved, contributing to the increase in common bean yields in regions such as Central America. Potential limits to the physiological heat tolerance in common bean may necessitate the introgression of tolerance from, or the production of alternative legume species, such as tepary bean (Phaseolus acutifolius), in areas of excessive heat stress.