Evaluation Of Adult Plant Resistance To Stripe Rust In Elite Wheat Cultivar Fan6and Its Derivatives

Breeding practice proved that the founder parents played an important role in wheat breeding. However, systematic evaluation of founder parents was still poor in the breeding process. Fan6is one of the founder parents in China with many excellent characteristics, including excellent resistance to stripe rust. In this study, Fan6and its derivatives, and intermediate parents were analyzed by using traits and SSR markers.1. The stripe rust resistance of Fan6and its derivatives was investigated by mixed physiological race. Fan6showed adult plant resistance to mixed physiological races in disease severity, incidence and disease index. Among the derivatives of Fan6, four cultivars showed immunity. These cultivars could be used in the genetic improvement of wheat resistance to stripe rust.2. Fan6and its derivatives, and intermediate parents were analyzed by using80SSR markers associated with adult plant resistance to strip rust. Among the80SSR markers,32were polymorphic, and the frequency of polymorphic markers was40%. A total of131alleles were detected. Alleles per locus ranged from2to12, and the average number of alleles was4.10. The alleles were transmitted to the progeny with the frequencies of0to100%. Eighteen alleles were amplified at18SSR loci in Fan6and could be found in over60%of the progeny. This indicated that the chromosomal loci in Fan6were selected under different pressure. 3. Compared with four parents (Dalizao, Chuanmai10, Shuwan761and Wanya2) of the first progeny, nine loci (Xwmc631, Xgwm359, Xwmc407, Xgwm501, Xgwml48, Xgwm539, Xgwm533, Xgwm299and Xgwm639) had unique alleles in Fan6. These unique alleles of fan6could be tracked form first to four generation by high frequencies at6loci (Xwmc631, Xgwm359, Xgwm501, Xgwm299and Xgwm639). Therefore, these unique alleles were continually selected.4Association between important chromosomal loci and traits was carried out by using the polymorphic markers. Six SSR markers were found to be associated with traits using association mapping. The results showed that1,3,5and1markers were associated with disease severity, infection type, incidence and disease index, respectively. Parts of the SSR markers were connected with several traits. Xgwm539were found to connect with disease severity, infection type, incidence, disease index and explained high phenotypic variance.5. Associated markers were compared with the markers which amplified unique alleles. Two markers Xgwm539and Xgwm299were associated with disease severity, infection type, incidence and disease index.