Abstract:

【Objective】 The objectives of this study were to characterize the allelic variation at Lr34/Yr18/Pm38 locus in 273 CIMMYT wheat cultivars (lines), evaluate their resistance against stripe rust, leaf rust and powdery mildew, and validate the functional markers for the locus. 【Method】 A total of 273 CIMMYT wheat genotypes were tested using a STS marker csLV34 and 5 functional markers cssfr1-cssfr5 which were developed based on a 3-bp deletion in the exon 11 of Lr34/Yr18/Pm38 gene, and were tested for stripe rust resistance in fields in Chengdu and CIMMYT, respectively, leaf rust in CIMMYT, and powdery mildew in Beijing. 【Result】 The results tested by the STS marker csLV34 showed a 96.7% identity to those of cssfr1-cssfr5. Of the 273 lines, 43 were characterized to have Lr34/Yr18/Pm38 resistance gene, with partial resistance against stripe rust, leaf rust and powdery mildew in field across different environments. 【Conclusion】 The 5 functional markers (cssfr1-cssfr5) could be used to detect the allelic variants in Lr34/Yr18/Pm38 locus, and 43 CIMMYT lines with Lr34/Yr18/Pm38 may be used in wheat breeding targeting for stripe rust, leaf rust and powdery mildew resistance with marker-assisted selection of cssfr3, cssfr4 and cssfr5.

Key words: Triticum aestivum L., Lr34/Yr18/Pm38, functional marker, slow rusting and mildewing resistance