| Wheat is one of the most popular crop all over the world. However, the yield decreased a lot because of stripe rust, powdery mildew and fusarium head blight. Resistant cultivars had been considered the most effective, low-cost, and safe way to control the disease. However, the rapid development of new races lead to the loss of resistance. It is necessary to take a rapid identification technology system for the analysis of resistance level and resistance genes to stripe rust, and the method could used for giving guidance for the application of the materials and for the evaluation of the resistance level of our country. In this way data support was offered for variety certification and genetic layout.One hundred and sixty elite varieties(lines) were investigated for race-specific resistance at the seedling stage in greenhouse and at adult plant stage in field for two croping seasons. Two types of disease nursery were established: one was artificial nursery inoculated two mixed prevalent races in Yangling, Shaanxi Province; the other was a natural infection of Pst in Tianshui, Gansu Province. Stripe rust resistance genes were postulated using molecular markers in combination phenotyping for the given Yr-genes, such as Yr1, Yr2, Yr5, Yr7, Yr9, Yr10, Yr15, Yr17, Yr18 and Yr26. In the method resistance level was evaluated by the combination of microscopic molecular detection and macroscopic phenotype. The results were as follows:1. Of all the one hundred and sixty wheat varieties(lines), there were two entries carrying seedling(all stage) resistance to stripe rust; there were thirteen entries carrying adult-plant resistance; there were 15 entries carrying adult plant resistance in 2012, while with the races changing, little resistant entries at the adult-plant growth stages were identified in 2013; seven entries had middle susceptibility to stripe rust, other 123 entries were susceptible to stripe rust. The presence of resistance genes Yr1, Yr2, Yr7, Yr9, Yr17 and Yr26 were identified in certain elite cultivars, in 4, 4, 5, 49, 4 and 21 entries, respectively. None carried Yr5, Yr10, Yr15 and Yr18 genes.2. What the object of the study was to evaluate the resistance level to stripe rust and Yr-genes of elite wheat in China. The way which was set up above had been used here.Of all the entries, none had seedling resistance to stripe rust; there were four entries carrying adult-plant resistance; there were ten entries carrying adult-plant resistance at Yangling artificial nursery, while few resistant entries were identified with the high disease pressure at Tianshui nature nursery; the other sixty were susceptible to stripe rust. The presence of resistance genes Yr9, Yr17 and Yr26 were identified by molecular detection, in 24, 4 and 5 entries, respectively. None carried Yr5, Yr10, Yr15 and Yr18 genes.3. It was found that there were 27 susceptibility materials,30 adult-plant stage resistance materials, 17 all stage resistance materials on stripe rust; The number of susceptibility, middle susceptibility, middle resistance and resistance on powdery mildew and fusarium head blight is: 13, 38, 19, 4 and 33, 33, 8, 0, respectively. By comprehensive analysis it was found that there were 23 materials carrying different degrees of resistance to stripe rust and powdery mildew, cluding 3 materials which were highly resistant to stripe rust and powdery mildew but were susceptibily to fusarium head blight and 10 materials were middle resistance to stripe rust and powdery mildew but were middle susceptibily to fusarium head blight; there were 5 materials carrying different degrees of stripe rust and fusarium head blight. SPW57-35 was middle resistance to all the three diseases. Space mutation was an effective method which could provide high resistance and multi-resistant materials for wheat breeding, especially, multi-resistant materials were good for appling in the future. |
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