Genomics-based approaches to improve drought tolerance of crops.

The genetic bases of the molecular, cellular and developmental responses to drought involve many gene functions regulated by water availability. Genomics-based approaches provide access to agronomically desirable alleles present at quantitative trait loci (QTLs) that affect such responses, thus enabling us to improve the drought tolerance and yield of crops under water-limited conditions more effectively. Marker-assisted selection is already helping breeders improve drought-related traits. Analysis of sequence data and gene products should facilitate the identification and cloning of genes at target QTLs. Based on such premises, we envision a quick broadening of our understanding of the genetic and functional basis of drought tolerance. Novel opportunities will be generated for tailoring new genotypes "by design". Harnessing the full potential of genomics-assisted breeding will require a multidisciplinary approach and an integrated knowledge of the molecular and physiological processes influencing tolerance to drought.