Genetic Dissection of Mechanisms Underlying Drought Tolerance in Wheat

Drought is a major cause of decrease in worldwide crop production. The 2006 drought dropped the total wheat yield by 46% in Australia. A way to improve the drought tolerance of crops varieties is to discover new genes and alleles that allow plants to grow and yield grain under water limited conditions. Although many Quantitative Trait Loci (QTL) have been identified in cereals for yield in dry environments, identifying the genes underlying these QTL is still challenging. Genomic resources have tremendously increased in the last years, which help making progress in genetic mapping and gene identification. Soon the issue will not lie in the lack of genetic information but rather in understanding and tracking complex phenotype such as drought tolerance. One way is to link physiological methods to genetics by dissecting complex traits into elementary and simpler biological parameters. Over a 10 years program, the ACPFG has cumulated QTL information on three genetic populations for yield, agronomical and morphological traits. More recently we also have identified QTL for physiological and cellular traits such as metabolites, plant growth, transpiration and leaf epidermal cells. Some of these loci overlap with QTL for yield in the same populations. These findings are a step-forward in understanding the function of these loci and identifying candidate genes for yield QTL under drought in wheat.