Genomic dissection of genotype x environment interactions conferring adaptation of cotton to arid conditions

The interaction of genotype with environment is of primary importance in ma ny aspects of genomic research and is a special priority in the study of ma jor crops grown in a wide range of environments. Water deficit, the major f actor limiting plant growth and crop productivity worldwide, is expected to increase with the spread of arid lands. In genetically equivalent cotton p opulations grown under well-watered arid water-limited conditions (the latt er is responsible for yield reduction of similar to 50% relative to well-wa tered conditions), productivity arid quality were shown to be partly accoun ted for by different quantitative trait loci (QTLs), indicating that adapta tion to both arid and favorable conditions can be combined in the same geno type. QTL mapping was also used to test the association between productivit y and quality under water deficit with a Suite of traits often found to dif fer between genotypes adapted to arid versus well-watered conditions. In th is study, only reduced plant osmotic potential was clearly implicated in im proved cotton productivity under arid conditions. Genomic tools and approac hes may expedite breeding of genotypes that respond favorably to specific e nvironments, help test roles of additional physiological factors, and guide the isolation of genes that protect crop performance under arid conditions toward improved adaptation of crops to arid cultivation.