Identification of SSR and EST-SSR Informative markers associated to leaf rust resistant in Aegilops tauschii in seedling and adult-plant stages

Aegilops tauschii Coss is an annual and diploid plant (2n = 2n = 14, DD) that grows as a wild weed in the highlands or plains near the shores of the high seas, from Turkey to China. Since the northern regions of Iran are considered as one of the most important centers of origin and diversity of this species, it is very important to identify sources of resistance to brown rust (wheat leaves) in these regions. In the present study, the resistance of rangeland species, Aegilops tauchii Coss., to six isolates of brown rust was evaluated in seedling and adult plant stages. SSR and EST-SSR markers with proper coverage on D genomes of wheat were applied to identify marker-trait association (MTA). Analysis of population genetic structure showed that the 100 investigated genotypes separated in two distinct sub-populations. Association analysis among markers and phenotypic data was conducted out based on the Kinship coefficients using generalized linear and mixed linear models. Significant associations among markers and traits obtained for amplified fragments of Xgwm2, Xgwm44 and Xgwm30 primers correspondingly located on 3D, 7D & 2D chromosomes, respectively. Furthermore, EST-SSR primers SWES186 and SWES92 correspondingly located on 2D & 7D chromosomes, respectively. These associated markers have the highest R2 coefficients for resistance level to leaf rust disease. Informative markers with association to most isolates could be exploited for genomic selection and early screening of genotypes for resistance to leaf rust.