Abstract:

From 102 synthetic wheat germplasms of Triticum durum and Aegilops tauschii, a germplasm CI108 with combination of GAN/Ae. squarrosa 201 conferring good resistance to stripe rust, with infection type (IT) of 0 or 0; grade, was identified through inoculating Chinese prevailing races of Puccinia striformis f. sp. Tritici（Pst），including CY28–CY32, and Shuiyuan 11-4. The results of genetic analysis suggested the stripe rust resistance gene in CI108 was controlled by a single nuclear dominate gene, temporarily termed YrC108. The results of gene postulation, in which the responses of CI108 and 25 wheat lines possessing known stripe rust resistance genes were evaluated to 30 races of Pst showed that CI108 conferred resistance to all 30 races of Pst. The response pattern of CI108 to the 30 races was different from those of the 23 lines containing known resistance genes but similar to those of K733 containing Yr24 and Lovin 13 containing Yr9+unknown gene. However, the degree of resistance of CI108 was different from those of K733 and Lovrin 13. By using an F₂ population of CI108/Mingxian 169 and BSA method, SSR markers associated with YrC108 were screened. We identified three SSR markers: Xgwm456 and Wmc419 located on one side of YrC108 with a genetic distance of 0.6 cM and 1.8 cM respectively, whereas Wmc413 located on the other side of YrC108 with a genetic distance of 0.6 cM. Furthermore, the markers could distinguish YrC108 from the resistance genes in K733 and Lovrin 13, suggesting that YrC108 should be a novel resistance gene.

Key words: Synthetic wheat, Stripe rust resistance gene, Gene postulation, Genetic analysis, SSR marker