Abstract
Cereal cyst nematode (CCN: Heterodera avenae Woll) causes a significant damage to wheat yield in the Kingdom of Saudi Arabia. Wheat cultivar Yecora Rojo and advanced lines derived from the cross between Yecora Rojo and local line (Sama) were sown in a field infected with CCN. Microsatellite markers linked to Cre1, Cre3, Cre5, Cre8, and CreY genes were used in this study. In addition, the presence of the peroxidase genes in wheat lines was investigated. Three groups of peroxidase genes (TaPrx111-A, TaPrx112-D, and TaPrx113-F) were found to be greatly induced by cereal cyst nematode in the resistance wheat line. In particular, parenchyma cells, where the nematode starts its feeding, were hyper-reactive to some probes belonging to (TaPrx112-D, and TaPrx113-F) groups. The field data showed significant differences in yield performance and CCN score. Four local lines were scored as resistant (KSU114, KSU118, KSU119 and L11-21). The highest grain yield was obtained from local lines KSU 110, KSU 118 and L11-21 compared to the check variety Yecora Rojo. Analysis of microsatellite markers linked with resistant genes revealed that there were significant differences in the presence of genes. Moreover, the results indicated that Cre3 gene located on chromosome 2DL, provided high levels of resistance to CCN in wheat genotypes using Xgwm301 marker. Also, there was a significant association between CCN resistance with Cre1 locus which explained 12% of the phenotypic variation in CCN infection. Gene-specific primer pairs for amplification of peroxidase genes revealed the presence of the TaPrx113-F peroxidase gene in all wheat genotypes. Moreover, cultivar Yocora Rojo and advanced line KSU 119 had TaPrx112-D peroxidase gene. On the other hand, the other wheat lines lacked the presence of TaPrx112-D peroxidase gene. The advanced line KSU 119 was resistant to CCN and contained Cre1, which was absent in susceptible cultivar Yecora Rojo. Therefore, the presence of peroxidase genes alone did not explain differences among wheat genotypes for CCN resistance. Amplification conditions for Cre3 and Cre1 loci were optimized, and used in marker-assisted selection to identify CCN-resistant wheat in the Saudi wheat cultivars. Data of this study emphasized the potentiality of identifying a highly productive CCN resistant cultivar.