Evaluation of leaf rust resistance in the Chinese wheat cultivar ‘Een1’

Abstract

Wheat cultivar Een1, 34 near isogenic lines (NILs), and two cultivars were used as plant materials to evaluate the resistance of Een1 to leaf rust disease. Infection type identification and gene postulation were carried out by inoculation of 12 Chinese Puccinia triticina (Pt) pathotypes. Based on the unique phenotype of Een1, we speculated that Een1 might carry Lr gene(s) different from the tested ones. The chromosomal locations for resistance gene to leaf rust disease was employed using SSR primers mapping the populations derived from the cross between Een1 and susceptible Thatcher. A total of 285 plants in the F2 population were tested by inoculating Pt pathotype FHNQ during the seedling stage. Results from the segregation analysis fits a ratio of 3:1 (${\chi }_{3:1}^{2}=2.37$, P = 0.12), indicating the presence of a single dominant gene in Een1 conferring resistance to FHNQ. A total of 1,255 simple sequence repeat (SSR) primers were first used to identify the likely linked markers based on bulk segregation analysis (BSA), and then those likely linked markers were further genotyped in the F2 population for linkage analysis. Our linkage analysis found that the resistance gene (LrE1) was distal to seven SSR loci on the long arm of chromosome 7B, with distances from 2.6 cM (Xgwm344) to 27.1 cM (Xgwm131). The closest marker Xgwm344 was further verified with F3 lines.