Some of Defence Mechanisms and Breeding Prospects of Drought Stress Tolerance in Common Bean (Phaseolus vulgaris L.)

Most of the common bean production in the world takes place under rainfed conditions and drought due to insufficient or unpredictable rainfall limits yield. Nearly 60% of bean production occurs in agricultural land prone to water deficit, where the costs of irrigation or the lack of precipitation are major difficulties for producers. Consequently, there is an increasing need to improve drought tolerance in common bean cultivars, where adaptive mechanisms to cope with this main abiotic stress include characters such as root architecture, growth habit, maturity acceleration, early flowering, shoot biomass accumulation and efficient assimilate redistribution towards seeds, contributing to an increased harvest index. With projections of expanding and more frequent drought in many regions, the tepary bean has the potential of being a game-changing technology, providing farmers with an alternative but similar and equally nutritious bean crop that will enhance their resilience to pending climate change. This review will highlight some of the unique features of tepary bean as a promising source for amelioration of drought stress tolerance in common bean.