An AFLP marker linked to the leaf rust resistance gene LrBi16 and test of allelism with Lr14a on chromosome arm 7BL

Leaf rust (LR), caused by Puccinia triticina, is one of the most widespread diseases of common wheat (Triticum aestivum L.) worldwide. The LR resistance gene LrBi16 has been mapped on chromosome arm 7BL in Chinese wheat cultivar Bimai 16 and was closely linked to SSR loci Xcfa2257 and Xgwm344 with genetic distances of 2.8 cM and 2.9 cM, respectively. In the present study, a total of 304 AFLP primer pairs were used to screen Bimai 16 and Thatcher and resistant and susceptible DNA bulks. The polymorphic AFLP marker P-ATT/M-CGC_{173 bp} was used to genotype F₂ and F₃ populations to identify markers more closely linked to LrBi16. Marker P-ATT/M-CGC_{173 bp} was tightly linked to LrBi16 with a genetic distance of 0.5 cM. As LrBi16 was mapped near the Lr14a locus, 809 F₂ plants from the Bimai 16/RL6013 (Lr14a) cross were inoculated with the Pt pathotype FHNQ to test the allelism of Lr14a and LrBi16. All of the F₂ plants were resistant to FHNQ (IT between; and 2), suggesting that Lr14a and LrBi16 are allelic.