الفهرس 
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Abstract
This investigation was carried out in the laboratories of molecular Genetics, Department of Genetics, Faculty of Agriculture, Ain Shams University during 2008-2010. Fifteen wheat varieties with different genetic background were used in this study as, 10 Hexaploid bread wheat varieties (Triticum aestivum L.), 4 Tetraploid varieties (Triticum durum) and one Alas Diploid wheat (Triticum dicoccum). The wheat varieties which were used in the present study were supplied by Agricultural Research center Giza, Egypt and Genetics Department, Faculty of Agriculture, Ain Shams University. were used in this study. The aim of this study are to:
(1) Detect thermo-tolerance for wheat varieties by heat shock proteins using SDS –PAGE.
(2) Test the expression of HSP gene by Reverse Transcriptase–Polymerase Chain Reaction (RT-PCR) Analysis.
(3) Characterize the 15 wheat varieties by using random amplified polymorphic DNA of the polymerase chain reaction (RAPD –PCR) analysis.
(1) Detect thermo-tolerance for wheat varieties by heat shock proteins using SDS – PAGE:
All 15 wheat varieties produced heat-shock proteins under the exposure of 37°C temperature in the comparison of the control treatment (25°C). Gemmeiza9 variety showed the maximum number of heat-shock protein (eight bands), whereas the lowest number of heat-shock proteins (one band) produced by three varieties; Bani-Swaif3, Sohag3 and Gemmeiza 7 .
Among the observed 25 protein bands via the SDS-PAGE for the 15 wheat varieties, only five bands had no relation with heat stress. The majority of protein bands (20 bands) were observed under heat stress conditions with different frequencies. The most frequently heat shock protein band was 8 kDa which observed in six wheat varieties (Bani-Swaif3, Sohag1, Gemmeiza1, Gemmeiza7, Ald and Wheater). While seven heat shock protein bands (140, 131, 93, 78, 72, 52, , 24 kDa) were observed each of them in just one wheat variety.
(2)Test the expression of HSP gene by Reverse Transcriptase–Polymerase Chain Reaction (RT-PCR) Analysis:
Expression of candidate HSP gene was tested using total RNA extracts of the five wheat varieties (Bani-Swaif 1, Sohag 1, Gemmeiza 1, Katila. and Alas) utilizing RT-PCR gene expression system. RT-PCR analysis showed one fragment with molecular weight about 250bp . This fragment was observed under control (25°C) and heat stress (37°C) in all five varieties; 2 tetraploid (Bani-Swaif 1 and Sohag 1), 2 hexoploid (one local Gemmeiza 1 and one exotic katila) and one diploid (Alas) with different density. The density of the produced fragment under control was lower than the density of PCR fragment under stress
In high temperature the gene expression which responsible for mRNA synthesis as a step to produce HSPs work in active case.
(3) Characterize the 15 wheat varieties by using random amplified polymorphic DNA of the polymerase chain reaction (RAPD –PCR) analysis:
Eight arbitrary random primers were used to determined RAPD-PCR of the 15 varieties; 10 hexaploid, 4 tetraploid and one diploid wheat genotypes. The highest number of PCR amplified fragments was (35) in cultivar Gemmeiza 9, while the lowest number of PCR amplified fragments (23) in Gemmeiza 1. The other varieties displayed different number of amplified fragments.
The primer OP-O13 gave the highest number of amplified fragments with all studied varieties (72 fragments), while the primer OP-O10 showed the lowest number of amplified fragments with all studied varieties (30 fragments). The primer OP-B10 gave the highest polymorphism percentage (100%), while primer OP-A03 gave the lowest polymorphism percentage (71.4%) .Out of 76 amplified products, 13.2 % were monomorphic, and 86.8 % were polymorphic.
The dendrogram divided the 15 wheat varieties into three clusters, cluster one included 5 cultivars, cluster two included 7 cultivars, while the cluster 3 included 3 varieties.
Within cluster 1, one sub-cluster between Sakha 93 and Alas. These sub-clusters joined with Gemmeiza 9 and all these three varieties joined with Gemmeiza 10. Cluster two was divided into 3 sub-cluster. Cluster three was divided into one sub-cluster.
The three hexaploid Egyptian varieties ( Gemmeiza 9,Sakha 93 and Gemmeiza 10) were presented in one cluster indicated that they possessed narrow genetic background, and they may be produced from one origin genotype. The majority of foreign hexaploid varieties found in other cluster (Cluster 2), three tetraploid varieties were present in one group (cluster 3), indicating that they may produced from one origin genotypes.
The genetic similarity ranged from 22 to 70% among the wheat varieties with an some average 46%. Some distinctive varieties showed high genetic similarity with other varieties such as Ald and Wheatear (70%), Sakha 93, Ald (66%) Wheatear, Star (69%), with some varieties displayed low genetic similarity, such as Katila, Alas (22%), Gemmeiza 1, Alas (28%) Bani-Swaif 1 and Sakha 93 (31%).