Abstract:

The Pm21 gene, originating from Haynaldia villosa (6AL/6VS), is one of the effective powdery mildew resistance genes. It was observed from chromosome analysis and resistant testing to powdery mildew that Pm21 on 6VS could be stably inherited when transferred to wheat. It is valuable for identification of the molecular markers linked to wheat powdery mildew resistance gene Pm21 in marker-assisted selection in wheat breeding practice. In this study, wheat-Haynaldia chromosome substitution line (6A/6V), translocation lines (6AL/6VS, 6DL/6VS) were used to identify molecular markers located in chromosome short arm 6VS by using RAPD, AFLP techniques, and to investigate the relationship between the molecular markers and Pm21. RAPD test indicated that a Haynaldia villosa chromosome 6VS-specific polymorphic DNA segment OPK08910 was amplified in 6A/6V substitution line, 6AL/6VS and 6DL/6VS translocation lines of wheat-H. villosa. AFLP analysis showed three H. villosa chromosome 6VS-specific polymorphic DNA sequences (264 bp, 218 bp, and 232 bp) could be amplified by three AFLP primer pairs, PstⅠ+AGG / MseⅠ+CAC, PstⅠ+ACC / MseⅠ+CCT and PstⅠ+AAG / MseⅠ+CGC in substitution line (6A/6V), translocation lines (6AL/6VS and 6DL/6VS) and H. villosa (VV). These AFLP markers of PstⅠ+AGG / MseⅠ+CAC-264, PstⅠ+ACC / MseⅠ+CCT-218 and PstⅠ+AAG / MseⅠ+CGC-232 which derived from 6VS, were found to be cosegregated with powdery mildew resistance gene Pm21. These molecular markers can be used as novel DNA markers for selecting powdery mildew resistance gene Pm21 in wheat breeding program.

Key words: Wheat powdery mildew, 6A/6V, 6AL/6VS, AFLP molecular marker, Marker-assited selection