الفهرس 
ACKNOWLEDGMENTOnly 14 pages are availabe for public view
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Abstract
1 – Nature of gene action for some important traits under normal and saline conditions. 2 - The potentiality of heterosis expression for agronomic characters, yield and its components and panicle characters under normal and saline conditions. 3 - Using SSR molecular markers to evaluate the genetic variation in the materials under study. Methods & Results: Two experiments were conducted at both natural saline conditions in El-serw and normal conditions in Sakha and the two experiments were replicated in the next year. Six parents (three CMS lines and three restorer lines) and their 9 F1 hybrids resulted from 3 x3 by Line x Tester were evaluated. Some of agronomic traits & yield and its components traits and panicle traits were studied as well as all the genotypes under this study were evaluated by SSR molecular markers. The results indicated to presence highly significant variations for genotypes, parents and crosses under normal and saline conditions as well as combined analysis for all studied traits. Also, mean squares of GCA for CMS lines and testers revealed highly significant variations for most traits under study at all conditions and combined data. The means showed that the hybrids IR70368A x Giza181R and IR58025A x Giza182R were the best for most traits under all conditions. On the other hand, the parental lines IR69625A and Giza178R were the best parents for most studied traits. Also, the results showed that the SSR molecular marker RM223 con be used to determined the salinity tolerant genetic backgrounds than the sensitive ones. Conclusion: it could be concluded that the hybrids IR70368A x Giza181R and IR58025A x Giza182R recorded significantly positive values and were most promising ones, for grain yield and most desirable characters and could be utilized as commercial hybrids under normal and saline conditions. Among the parents, the CMS IR69625A as female line and Giza178R as restorer line were found to have favorable genes for the most studied characters then it could be used in hybrid rice breeding programme. Also, the molecular marker from the type SSR, RM223 could be used in classification of salinity tolerant genetic backgrounds than the sensitive ones. In addition, due to the importance of additive gene action in the gene expression for most studied traits, it could be suggested that the selection breeding program is the proper to improve these traits under normal and saline conditions.