Studies On The Slow Rusting Resistance And The Chromosomal Location Of Pm Genes By Molecular Marker In Wheat

Slow-rusting resistance is generally conferred by several additive minor genes that individually give partial resistance against many rust pathotypes. In this study, we investigated the resistance mechanisms of a number of Chinese wheat lines and the application of the molecular marker mapping the resistance gene.Initial work involved the postulation of seedling resistance genes against Puccinia recondita in 46 Chinese wheat lines. In 28 of these lines, only 6 named Lr genes were involved: Lr1, Lr10, Lr13, Lr14a, Lr16 and Lr26. Lr26 was the most common gene and was found to be present in nearly 40% of tested lines (46 lines). This indicates that Chinese wheats probably have a narrow genetic background for resistance to leaf rust.Slow rusting resistance was initially tested by observation of severity and AUDPC in the field of the 46 lines. Fourteen of these showed a slow-rusting component. Further glasshouse analysis of three of the lines showed that cultivar Kunqiao#28 had lower receptivity, Chinghuang#3 had a longer latent period and Yehe had smaller pustules, lower receptivity and a longer latent period. Genetic analysis of Kunqiao#28 and Chinghuang#3 indicate that 3 minor genes are likely to contribute to the slow-rusting character of these lines.Resistance to stripe rust was also investigated on a number of lines. Chuanyu 12 resistance appears to be controlled by a major gene while Saar, Tukuru and Chapio have Yr18 complemented with 2-3 other slow rusting genes. This information will facilitate the incorporation of slow-rusting resistance into breeding programs.Genetic study of the F3 lines of cross "87-12/288//T9062" showed a dominant major resistance gene to powdery mildew was temporarily designated G288. SSR marker Xgwm164 located in chromosome 1A and Dp532 were associated with the resistant gene, G288.