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. (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) Identify the gene coding for heat shock proteins in wheat: (4) Characterize the 15 wheat varieties by using random amplified polymorphic DNA of the polymerase chain reaction (RAPD – PCR) analysis: