Abstract: Lr34 and Yr18 are important slow rusting resistance genes that have been widely used in many countries. The aim of this study was to identify Lr34/Yr18 genes in 231 Chinese wheat cultivars and 422 landraces using an STS marker csLV34, which can amplify a 150-bp and a 229-bp fragment in the genotypes with and without Lr34/Yr18, respectively. The results indicated that only 14 genotypes carried the resistance genes Lr34/Yr18 in the improved wheat cultivars, with a frequency of 6.1%. Different frequencies were found in wheat cultivars from different zones, which were 0, 3.0%, 21.4%, 16.7%, and 33.3% in North Plain Winter Wheat Region (NPWWR), Yellow-Huai Facultative Winter Wheat Region (YHFWWR), Middle-Lower Yangtze Valley Winter Wheat Region (MLYVWWR), Southwest Winter Wheat Region (SWWR), and Northwest Spring Wheat Region (NSWR), respectively. Whereas, 85.1% of 422 landraces contained Lr34/Yr18, with the frequencies of 89.6%, 77.4%, 93.1%, 93.8%, 96.6%, and 61.1% in NPWWR, YHFWWR, MLYVWWR, SWWR, Southern China Winter Wheat Region (SCWWR) and NSWR, re-spectively. The marker csLV34 exhibited a good repeatability, and can be therefore used for the identification of Lr34/Yr18 in wheat breeding programs.

Key words: Common wheat (Triticum aestivum L.), Lr34/Yr18, STS marker csLV34, Marker-assisted selection