Evaluation of Stem Reserves and Remobilization in Barley lines and cultivars under Terminal Drought Stress

Terminal drought is one of the major factors limiting the yield of barley. Under this condition, Barley crops grown may depend more on stem reserves for grain filling than on current photosynthesis. To investigation the effects of terminal drought on yield, stem reserves and the mechanism of remobilization in 6 barley breeding lines and genotypes, the experiment was conducted in a split-plot design with three replications (block) at two controlled plots )well-watered and drought stressed. Plants were grown under well-watered conditions until anthesis; the drought treatment was started by withholding water at the anthesis. At 7-d intervals after anthesis (in six stages) peduncle, penultimate and lower internodes samples were collected from well-watered and drought-stressed plants. Internodes length, weight and specific weight measured in 6 date of harvest. The results showed that maximum accumulation and release of stored, was found in penultimate followed by lower internodes. The rate of dry matter translocation was much higher in drought stress condition. Dry matter mobilized from penultimate was significantly correlated with grain yield (r2= 0.99) in droughted plants. Two barley genotypes Yousef and Moroco had highest and lowest dry matter translocation and remobilization efficiency respectively. Significant genotypic variations for accumulation and remobilization were observed under both conditions indicated that these traits can be manipulated in barley breeding programs.