Effect of post-anthesis water deficiency on storage capacity and contribution of stem reserves to the growing grains of wheat cultivars

The experiment described here was carried out to determine the effects of post-anthesis water deficiency stress on dry matter and carbohydrate accumulation and their remobilization from different parts of stem to the growing grain in different wheat cultivars. To this end, an experiment was laid out as a split-plot arranged in a randomized completed block design with three replications during the years 2010-2011. The results showed that post-anthesis water deficit significantly decreased grain yield, TGW and grain number per spike and biomass in evaluated cultivars. The results showed that in all evaluated cultivars maximum weight of peduncle, penultimate and lower internodes, on average, were reached at 14 and 7 days after anthesis and at anthesis, respectively. Post-anthesis water deficiency stress had no significant effect on internodes length and stem weight, but, significantly increased dry matter remobilization and remobilization efficiency of lower internodes by 16.8% and 17%, respectively. Lower internodes had the highest storage capacity of dry matter and remobilization efficiency. Our analyses suggest that, with respect to high amount of dry matter accumulation in lower internodes, increasing of remobilization efficiency of lower internodes can significantly raises grain yield of wheat cultivars especially in arid and semi-arid regions.