الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The objectives of this study are to investigate the population structure of 70 Egyptian, Syrain and Iranian wheat accessions and to identify some markers associated with salinity tolerance in bread wheat. In addition to identify some genes that control some important agronomic parameters of wheat under salinity stress.
The wheat germplasm panel was consisted of 70 accessions obtained from Egypt, Syria and Iran. The assessment of salinity tolerance was conducted over the years of 2018 and 2019 in the green house of Agricultural genetic Engineering research institute (AGERI), Agricultural Research Institute (ARC), and the experimental filed of faculty of environmental agricultural sciences, Suez university in Arish , Sinai, Egypt. This subset was chosen from the International Center for Agricultural Research in the Dry Areas (ICARDA) and Agricultural Research Center gene banks, Giza, Egypt. The genome association analysis (GWAS) and population structure analysis was conducted using six SCoT, five SSR and 93 SNP markers.
A total number of 61 PCR-bands were revealed using SSR and SCoT primers, where SCoT analysis provided a higher number of bands (46 bands) compared to SSR analysis (15 bands). The maximum number of bands was obtained from SCoT-05 primer (10 bands). Additionally, the total number of polymorphic bands was 48 bands, where SCoT-10, and SCoT-01
SUMMARY
primers revealed the maximum number of polymorphic bands (eight bands). The PCR primers of SCoT-02 and SSR-01 revealed the maximum percentage of polymorphism (100%). On the other hand, out of the 91 SNP primers used for SNP genotyping, only 17 makers were monomorphic.
Analysis of the structure using allele frequency of Egyptian, Syrian and Iranian wheat genotypes indicated that these genotypes belong to four different population groups. Where, for the most portion, Egyptian, Syrian and Iranian genotypes were clustered depending on their country of origin. On the other hand, some genotypes showed a type of genetic migration, which could be caused by varietal adaptation. Similar results were retrieved using the phylogenetic analysis. Most genotypes were almost clustered, depending on their geographical origin, although some Egyptian genotypes were clustered with the Iranian and Syrian genotypes, which could indicate their source of origin. Such analysis could indicated a number of potential foreign genotypes that could be successfully adapted in the Egyptian environment through local breeding programmes.
SNP genotyping was used to detect genes that are related to wheat response to salinity stress. GWAS analysis revealed 13 significant SNP markers that were. These markers are distributed across the chromosomes of 7B (3 markers), 6A (3 markers), 5A (2 markers), 2B (1 marker), 2A (1 marker), 5B (1 marker), 3B (1 marker), and 1B (1 marker) . The effect of these markers on STR trait was ranged from -0.56 (BS00076622 marker) to 0.469
SUMMARY
(BS00064146 and BS00101408 markers). DF trait was correlated with four SNP markers (BS00024921, BS00083630, BS00078124, and BS00038820
markers), where its effect were ranged from -2.544 (BS00078124 marker) to 2.526 (BS00038820, and BS00024921 markers). Some SNP markers showed correlation with multiple traits such as BS00038820 (DF and PH traits), BS00107837 (NS and NT traits), and BS00089954 (NS and STR traits) markers.
By studying genes located near the SNP markers associated with wheat agronomic traits under salinity, 13 different genes were identified. Most of these genes included cytochrome P450 709B2, MALE DISCOV- ERER 2, STAY-GREEN, phosphatidylinositol 4-phosphate 5-kinase 9, monosaccharide-sensing 2, beta-amylase, 3beta-hydroxys- teroid-dehydrog- enase /decarboxylase, and disease resistance RPM1. Most of these genes were reported to be highly associated with salinity tolerance in different plant species.
Our reported salinity-associated genes can provide a more com- prehensive blueprint for salinity tolerance in wheat bread. These genes can be studied using gene expression technologies to identify possible protein-protein interaction networks that control wheat response to salinity stress. In addition, the SNP marker technology has shown its utility in supplying more detailed molecular markers can be used for marker-assisted selection in local and international breeding programs.