Remobilization of stem soluble carbohydrates in bread wheat under terminal drought stress

Mutant genetic materials are valuable tools for understanding the physiology of remobilization and could be useful in the breeding of drought tolerant varieties. Two advanced mutant lines of bread wheat (T-67-60 and T-65-7-1) along with their wild type (Tabasi Cv.) were planted at two moisture conditions (normal and 30-40% of field capacity) as a factorial experiment in format of completely randomized design with three replications. Drought treatment initiated at full heading stage (Zadoks 60) and soluble carbohydrates were measured 5 times (0, 7, 14, 21 and 28 days after anthesis) in the stem internodes, separately. Based on the results it could be said that changes in the receiving signals for senescence phenomena under drought stress, capability of the sink, the rate of the reserves assimilated before anthesis and the use of reserves capacity over stem are the factors affecting the differences of genotypes in remobilization of stem soluble carbohydrates under drought stress. It seems that under drought stress mutant line T-65-7-1 was significantly better than wild type cultivar in terms of remobilization and its efficiency and also for faster receiving signals of senescence (as a stimulating factor of remobilization), higher capability of the sink (more grain yield) and higher reserve capacity (higher maximum soluble carbohydrate concentration and specific content). Also, mutant line T-65-7-1 has utilized full ability of all parts of the stem for remobilizing soluble carbohydrates during grain filling.