Breeding for Drought Stress Resistance in Plants

Most cropping environments worldwide are suboptimal for plant growth and reproduction. Unfavorable environmental conditions prevent crops from attaining their full yield potential. Abiotic stresses including heat, cold, drought, salinity, and flooding have a major impact on world agriculture, reducing by 50% the average yield for most crop plants. Among these, water scarcity is the major factor limiting the expansion of agriculture and the single leading cause of crop losses worldwide. With the impact of climate change and demographic growth looming, stress-tolerant varieties and climateresilient crops emerge as relevant and necessary targets to ensure global food security and to improve sustainability in agriculture. Breeding of crops with enhanced stresses tolerance has been particularly compelling, as the related agronomic traits are complex and quantitative in nature, often associated to several loci exhibiting additive effects. Advances in plant genomics have greatly contributed to dissect such complex traits, unraveling the mechanisms underlying the plant response to stress, and opening unprecedented avenues in breeding improved varieties against unfavorable environmental conditions. This chapter will focus on recent successful stories in molecular breeding and biotechnological strategies for crop improvement against abiotic stress, with particular emphasis on drought tolerance.