Abstract
Terminal drought is an increasing risk for wheat production in many parts of the world, especially those with mediterranean type climate. The improvement of drought tolerance has been identified as a research priority. Under terminal drought, the impact of stem carbohydrate remobilization makes significant contributions to grain filling. Our study showed that the stem water soluble carbohydrate (WSC, main components fructan) level is not, on its own, a reliable criterion for the drought tolerance, the performance of the key enzymes involved in the WSC remobilization, which varied among different varieties, were critical in the terminal drought response. The genes involved in the mobilization of stem WSC, 1-FEHs and 6-FEHs (fructan exohydrolases), have been studied in detail to define their role in contributing to water deficit tolerance. The study includes the isolation of mutations where genes of interest have been deleted.