الفهرس 
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Abstract
This study aimed to : Wheat (Triticum aestivum L.), as nutritive crop, considered one of the most important cereal crops in Egypt as well as in many parts of the world. the present work was concerned with the response of wheat genotypes to stem rust disease at different locations under filed conditions in Egypt, and the epidemiological parameters of the level of partial resistance.
Objectives :
1- Identifying response of wheat genotypes to stem rust disease at different locations under filed conditions in Egypt.
2-Measuring the field resistance at plant adult stage.
3-Impact of stem rust infection on grain yield.
4- Identifying the nature of resistance to wheat stem rust disease.
5-Detecting the adult plant resistance genes for stem rust in the studied wheat cultivars under field conditions by.
6-Identifying stem rust resistance genes (s) in selected Egyptian wheat cultivars using PCR-based molecular marker techniques.
Methods & results : Stem rust resistance genes i.e. Sr 2 complex, Sr 24, Sr 26, Sr 31, Sr 32, Sr 33, Sr 36, Sr 38, Sr 39 and Sr 40 either singly or in combination with other genes provides a good degree of resistance, this study indicate the importance of the two Egyptian bread wheat cultivars Sakha 94, Sids 1, Sids 13 ,Gemmeiza 10 and Shandwel 1 as a source of adult-plant stem rust resistance genes. the wheat cultivars which showed high stem rust disease severity exhibited maximum values of AUDPC and yield losses%, the wheat cultivars Sids 1 and Shandwel 1 gave the highest yield (low level of loss %) among all tested cultivars , while cultivars Misr 1, Sohag 3, Misr 2, Beni Sweif 5 and Giza 168 gave the lowest yield (high level of loss %) in grain yield. Genetic analysis was conducted to identify the genes governing adult plant resistance to stem rust. Out of the six wheat cultivars, the two cultivars Sids 1 and Gemmeiza 10 expected to carry Sr 11, Sr 32, Sr 33 and Sr 40 adult-plant stem rust resistance genes. molecular markers analysis. expected that Sr 40 present in all the examined thirteen Egyptian bread wheat cultivars Sr 22, Sr 24 and Sr 32 expected to be present in eleven cultivars. Sr 25, Sr 28 and Sr 2 complex are expected to be present in 10, 9, and 8 cultivars, respectively. Sr 33 expected to be present in only three Egyptian bread wheat cultivars .Adult plant resistance in the tested wheat cultivars is a quantitative trait (not simple), with dominance effects in its genetic expression. he heritability in broad-sence ranged from 88.85% to 97.30%. indicated that the selection for adult plant resistance materials in the early generations was possible, while delaying it to late ones is more effective, due to the importance role of dominance effectives in the expression of this trait.
Conclusion : The results of this study indicate the importance of the two Egyptian bread wheat cultivars Sakha 94, Sids 1, Sids 13 ,Gemmeiza 10 and Shandwel 1, Stem rust resistance genes i.e. Sr 2 complex, Sr 24, Sr 26, Sr 31, Sr 32, Sr 33, Sr 36, Sr 38, Sr 39 and Sr 40 as a source of adult-plant stem rust resistance genes which could be utilized in wheat breeding program for improving stem rust resistance in Egypt.