DEVELOPMENT OF SSR & STS MOLECULAR MARKERS ASSO-CIATED WITH STEM RUST RESISTANCE IN BREAD WHEAT (Triticum aestivum L.)

Screening experiment was performed on twelve genotypes of bread wheat (Ttriticum aestivum L.) to select the most stem rust resistant genotype (Misr1) and the most stem rust susceptible genotypes (Line 37 and Line 92) according to stem rust reaction. Crosses were carried out between the resistant parent (Misr1) with each of the susceptible parents as well as between the two susceptible parents (Line 37 and Line 92) to obtain the F1 kernels. Some of the F1 kernels were sown in the field and selfed to obtain the F2 kernels for each cross. These three selected parents, their F1 and the most resistant and susceptible F2 plant groups for the three crosses were evaluated for their response to stem rust resistance by recording some stem rust–related traits. However, infected condition caused a reduction in the values of all traits except spike length and number of spikelets per spike traits. The three parents, their F1 plants and some individual plants of the two contrasting F2 plant groups (the most resistant and the most susceptible F2 groups) for the three crosses were used to develop some molecular genetic markers associated with stem rust resistance using SSR and STS markers. The results indicated the presence of two positive markers out of the three SSR and three STS primers which used in this study. Sr2 (SSR) and Sr25 (STS) primers gave positive markers at fragment sizes of 120 and 130 bp, respectively, for stem rust resistance that could be considered as reliable markers for stem rust resistance in bread wheat (Ttriticum aestivum L.).