الفهرس 
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Abstract
The present study was carried out at El-Gemmeiza Research Station, Wheat Research Department, Field Crop Research Institute, Agriculture Research Centre (ARC), Egypt and the Biotechnology Laboratory, Crop Sciences Department, Faculty of Agriculture, Elshatby, Alexandria University, Egypt, during the period from 2013 to 2017 to investigate the response of 40 wheat genotype to normal and drought stress conditions, in addition to characterize the 40 wheat genotypes under drought stress using SSR markers. Wheat genotypes were sown in the two winter season of 2013/2014 and 2014/2015.The most important results obtained from this study could be
summarized in the following:
I- Field Experiment: I.1. Agronomic traits: The results obtained from agronomic characters indicated that drought applied at both vegetative and reproductive stages caused significant reduction in those traits compared to normally irrigated conditions. Reduction in grain yield reached 20 %, as an average of all genotypes.
1- Analysis of variance, expressed a significant variation with all agronomic traits, as influenced by irrigation levels and wheat genotypes, while their interactions for I*G had seven significant traits out of eleven. On the other hand, the three factor interaction showed significance only with three traits out of eleven studied traits. In focus to the grain yield trait, data revealed that the grain yield (GY), significantly decreased under drought stress treatment across wheat genotypes in the two seasons.
2- Means grain yield as influenced by genotypes indicated that the double haploid group gave the lowest grain yield (3.80-4.35 t / ha.), DH 36 (3.80 ton / ha.), DH 75 (3.82 ton / ha.), DH 74 (4.10 ton / ha.), DH 40 (4.12 ton / ha.) and DH 38 (4.35 ton / ha.). Conversely genotypes Misr 1 (6.01 ton / ha.), Shandaweel 1 (5.94 ton / ha.), Gemmeiza 11 (5.80 ton / ha.), Gemmeiza 10 and Misr 2 (5.68 ton / ha.) and Gemmeiza 9 (5.67 ton / ha.) gaved the highest GY.
3- Means of grain yield as influenced by the interaction between seasons* irrigation levels * genotypes revealed that, progressive decrease in grain yield Summary 100< of wheat genotypes was observed in drought stressed treatment, compared to normal irrigation, in the two seasons. In the first season under normal irrigation genotypes, Gemmeiza 11 gave the highest GY, and DH 40 gave the lowest GY, while under drought conditions in the same season Veery gave the highest GY, and DH 36 gave the lowest GY. On the other hand, Shandaweel 1 was the superior genotype and DH 75 gave the lowest GY in the S2 under normal irrigation. Genotypes Sakha 93 and DH 75 recorded the highest and lowest values respectively under drought condition in S2.
4- In the first season, Gemmeiza group and Misr 1 were the highest in grain yield with a range of 5.703 to 5.943 ton / ha under normal conditions. The reduction in those genotypes under drought treatment ranged from 21 to 32 %. In the second season, the highest grain yields were recorded for Gemmeiza 10, Misr 1, Sids 12, Shandaweel 1 and Sids 14 with a range of 7.667 to 8.333 ton / ha. The reduction in grain yield for the genotypes ranged from 22 to 39 %.