| Stripe rust and powdery mildew, caused by Puccinia striiformis f. sp. tirtici and Blumeria graminis f. sp. tritici, respectively, are two important diseases in wheat production worldwide. Breeding and growing of resistant varieties are the most economical, effective and environment friendly way to control the disease. Characterization and utilization of resistance genes are essential for breeding resistant wheat cultivars. Roegneria kamoji (syn. Elymus tsukushiensis Honda,2n=6x=42, StStYYHH) is a perennial species in Roegneria of the tribe Triticeae (Poaceae) with large fleshy leaves. R. kamoji is a member of the tertiary gene pool of common wheat and it can provide a useful source of new genetic variation for wheat improvement.The objectives of this study were:(1) to broaden genetic diversity and develop new anti-disease cultivars of wheat crops,34 populations of R. kamoji (33 of them are wild germplasms, one is variety) which introduced from overseas and domestic regions were evaluated on resistance to stripe rust and powdery mildew at adult-plant stage in the fields; (2) to determine the resistance of ZY 1007 and Gansi No.1 to the predominant races of Pst in China, which including stripe rust physiological strains CYR29, CYR32, CYR33, PST-V26, G 22-8, G 22-9, G 22-14 and the mixed urediospores; (3) to analyze the resistant inheritance by testing the F1 and F2 populations of Gansi No.1× ZY 1007 in a field inoculated with the mixed urediospores. The main results are summarized as follows:1. Adult-plant resistance results indicated that the resistance of the germplasm resources were quite different. The variation range of Severity level of disease, Incidence and Disease index of stripe rust for the 34 populations of R. kamoji were 11.49%-50.46%, 19.85%-74.24% and 2.63-37.60, with a coefficient of variation of 30.01%,26.54% and 49.67%, respectively. The Infection type and Occurrence degree index were 1-4 and 1-5, respectively. Among the various indexes were significantly positive correlation (P< 0.01). All of the above indexes were analyzed by tree diagram of cluster analysis, the results showed that 34 populations of R. kamoji were clustered into 4 groups, namely high resistance (HR), middle resistance (MR), middle susceptibility (MS) and high susceptibility (HS). And the percentage of each resistance classification was 17.65%, 11.76%,50.00% and 20.59%, respectively. The variation range of Infection type, Severity level of disease and Ratio of diseased plant of powdery mildew for the 34 populations of R. kamoji were 0-4,0-60.00% and 0-100%. The proposed resistance classification were 12 populations for HR,5 populations for MR,11 populations for MS and 6 populations for HS. The percentage of each resistance classification was 35.29%,14.71%,32.35% and 17.65%, respectively. The results suggested that accessions of ZY 1007 and Pr 87-88344 could preferably resist to both stripe rust and powdery mildew.2. In the seedling test with CYR29, CYR32, CYR33, PST-V26, G 22-8, G 22-9, G 22-14 and the mixed urediospores in the greenhouse, Gansi No.l was susceptible to all of them, whereas ZY 1007 was resistant to stripe rust physiological strains CYR29, CYR33 and PST-V26, but susceptible to CYR32, G 22-8, G 22-9, G 22-14 and the mixed urediospores. There may be new effective resistance gene(s) to the new virulent mutation strain PST-V26 in ZY 1007.3. ZY 1007 and all the observed 11 hybrid F1 plants were resistant, while plants of Gansi No.1 were susceptible. Among the 221 F2 plants,168 plants were resistant and 53 were susceptible, segregation of resistant and susceptible plants fit 3R:1S ratio (?2= 0.074, P> 0.75). All of the above data revealed that the resistance of stripe rust in ZY 1007 was controlled by a single dominant gene, here we tentatively designated it as YrK1007, which may be a typical adult-plant resistance gene to the mixed predominant races of Pst in China. |
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