Abstract: 【Objective】 The objective of this study is to determine the types of stripe rust resistance, the potential resistance genes and the genetic diversity in Chinese 40 wheat landraces and 40 commercial cultivars grown in Gansu Province, that will provide reference information for the selection and utilization of stripe rust resistance resources. 【Method】 For stripe rust resistance identification of 80 wheat accessions, the prevalent race CYR32 of Puccinia striiformis f. sp. tritici and 12 mixed races including prevalent races and important pathogenic isolates were used for inoculation at the seedling stage in greenhouse and adult-plant stage in nursery field, respectively. Thirty wheat lines with known resistance genes, 17 international and European stripe rust differential varieties, 80 landraces and commercial cultivars and susceptible control Mingxian 169 were inoculated with 25 races of different virulences of P. striiformis at the seedling stage in greenhouse. Besides the comparison of resistance spectrum to stripe rust and pedigree of these wheat cultivars, the tested cultivars and standard cultivars were compared to postulate the possible resistance genes or their combinations contained in the landraces and commercial wheat cultivars according to their infection types to different races. For genetically classifying the cultivars using their pedigree information, the genetic similarity coefficient was calculated by software NTSYSpc-2.2, and a distance tree was constructed using UPGMA (unweighted pair-group mean average). 【Result】 Most of the tested cultivars showed a high level of stripe rust resistance at adult-plant stage, except that Qingnong 1, Qingnong 2 and Hongkexiaomai 2 were susceptible. Twenty cultivars such as Lantian 3, Lantian 4 and Lantian 6 exhibited slow rusting resistance, and the other cultivars ranged in resistance from moderate level to immunity. The resistance phynotype of the tested cultivars was mainly provided by all-stage resistance and partly by adult-plant resistance. Most commercial cultivars from Gansu Province contain Yr9, Yr24 and/or Yr26, and some of them also contain other unknown genes. For instance, Yr9 was postulated to be present in cultivars Lantian 1, Lantian 14, Lantian 17, Lantian 21, Qingnong 4; Yr24 in cultivars Lantian 24, Zhongliang 04335 and Tianxuan 51; and Yr26 in cultivars Lantian 17, Lantian 23, Lantian 25, Zhongliang 17, Zhongliang 04260 and Tianxuan 43, Tianxuan 48. Among the landraces, 19 of them were found to carry unknown resistance gene(s) alone and the other landraces may contain Yr1, Yr2, Yr4, Yr6, Yr7, Yr8 and/or Yr40. Results of the cluster analysis also indicated that the commercial wheat cultivars possessed higher levels of genetic similarity and had wider resistance spectra than the landraces. The similar coefficient of resistance types among the 40 commercial wheat cultivars varied from 0.30 to 1.00. They were classified into 3 groups when the similar coefficient value was 0.70: one group included Lantian 15 alone; the other group included Qingnong 1 and Qingnong 2; and the third one included 37 cultivars. But the range of resistance spectrum was different among the landraces, which possess a higher level of genetic diversity. The similar coefficient of resistance types was from 0.38 to 1.00, and the 40 cultivars were classified into 9 groups when the similar coefficient value was 0.70. 【Conclusion】All tested wheat cultivars showed a higher level of stripe rust resistance. Compared to the commercial wheat cultivars in Gansu, landraces possessed abundant genetic diversity and more effective stripe rust resistance gene(s), so they can be used as stripe rust resistance resources in wheat breeding programs.

Key words: wheat stripe rust, common wheat, landrace, commercial cultivars in Gansu Province, resistance gene, gene postulation