Breeding Strategies to Enhance Drought Tolerance in Crops

Global climate change is expected to increase the occurrence and severity of drought episodes due to increasing temperatures and evapotranspiration. Therefore, food security in the twenty-first century will increasingly depend on the release of new cultivars with improved adaptation to drought conditions. However, selection for drought tolerance is difficult due to a complex genotype and by environment interactions. Recent progress in genomics makes possible a more efficient assessment and enhanced diversity in germplasm collections, introgression of valuable traits from new sources and identification of the genes that control key traits. Marker-assisted selection helps to reduce the environmental impact of breeder selection. Significant advances have been made in the development of in vitro selection methods. The broader use of traits from alien species and the manipulation of heterosis and polyploidy create new perspectives for improving yield potential and adaptation to abiotic stresses. The use of the knowledge generated by these approaches should clarify the functional basis of drought adaptation traits. The integration of these new methods and tools into breeding programs and their potential impact in the development of drought-tolerant germplasm are discussed.