Abstract
FIFTY bread wheat lines were evaluated for drought tolerance and compared to six local cultivars under three water regimes (Well-watered = 0.8 Evapotranspiration (ETp), Mild drought stress = 0.6 ETp and severe drought stress = 0.4 ETp.). Eight agronomic traits were evaluated, i.e. days to heading, number of spikes/plant, 100-kernel weight (g), relative water content (%), chlorophyll concentration (mu g cm(-2)), grain yield/plant (g), harvest index and water use efficiency (kg/m(3)) under normal and stress conditions. Analysis of variance showed highly significant variations among the tested lines. As an average of all tested lines chlorophyll concentration was the most affected trait by drought followed by grain yield per plant and WUE, while harvest index showed the lowest reduction due to drought stress. Five lines (1, 5, 11, 41 and 42) showed high performance in grain yield/plant and surpassed all local varieties under all conditions. The sequence related amplified polymorphism (SRAP) technique was used for the detection of markers associated with drought tolerance. SRAP was able to discriminate between the bulked-DNA of high and low performance lines in some evaluated traits under drought. Moreover, several unique and specific bands for high-and low-bulked lines were generated exposing the efficiency of SRAP in genotyping and diversity analysis. Evaluation of WUE showed its efficiency in differentiating among the tested lines and was in agreement with SRAP analysis which showed the maximum number of specific markers when the high-and low-WUE bulks were compared unlike the other traits. The generated bands could serve preliminarily as selectable markers for drought tolerance in wheat.