| Rice false smut, caused by Ustilaginoidea virens (Cooke) Takahashi, is a panicle fungal disease. Since the 1980s, the rice disease has risen as one of the main rice diseases from one secondary disease in China, because of the widespread promotion of hybrid rice and the abuse of stimulation, which has drawn great attention in the plant protection field and rice breeding field. The article analyzed genetic diversity of the pathogen from the same period, the same area, and the same host materials, which can provide theoretical basis for resistance breeding against rice false smut. Based on the identification of resistance to on series combinations of rice restorer line YaHui 2115-a good fertility restoring line of rice, we wish to get a new combination with high quality and ease and high resistance to rice false smut, and it will establish foundation for controlling the disease by resistance of rice varieties.In this experiment, we made the biology characteristic observation and analysis of genetic diversity of 54 single spore strains isolated from Pu Jiang 6 that is high sensitive to rice false smut at Caoba, Ya'an, Sichuan province. The test shows that colony color mainly can be divided into 4 kinds:white, yellow-green, yellow, green, and it account for 13.0%,27.8%,48.1% andll.1% of the strains. There are 2 strains with large spore yield,3.7% of the total strains; 10 strains with middle spore yield, 18.5% of the total strains; 38 strains with small spore yield,70.4% of the total strains; and 4 strains with no spore yield,7.4% of the total strains. And, the slowest growing strain is 85-2-22. with1.78±0.05 mm/d, and the fastest growing strain is 97-3-6, with 3.02±0.18 mm/d, and most of the strains are in a middle level of growth rate.2 makers, abundant SNP loci and easy to amplify single spore strains based on MLST analysis of Ustilaginoidea virens, are chosen to amplify of 54 single spore strains. Only marker1 amplifies all 54 strains. According to sequencing results and the basis of adjacency method (NJ), molecular tree is established by using of the MEGA5.1 software.54 strains can be divided into 5 groups:? class has 24 strains,44.4% of the total groups; ? class has 1 strain,1.9% of the total groups; ? class has 13 strains, 24.1% of the total groups; ? class has 6 strains,1.1% of the total groups; ? class has 10 strains,18.5% of the total groups. Group I is the dominant group. The results suggest that there are genetic differences in pathogens from the same ears, even the same rice curveball, but most of the strains have similar genetic backgrounds. Each of genetic groups contains all biological characteristics of strains (spore yield, colony color, growthrate of colony).Taken together, there are no correlation between gene groups of strains and their biological characteristics.We identified and evaluated the resistance of rice false smut on restorer line YaHui 2115 and its 25 combinations at 5sowing periods at Caoba, Ya'an. The results shows that there are 72% with high resistance, the rest 28% of combinations are middle resistant at the first sowing time; even 96% of combinations are high resistant, the other 4% are middle resistant at the second sowing time; and 80% of combinations with high resistance.All above show that series combinations of restorer line YaHui 2115 have good resisitance to rice false smut.As the sowing time delayed, combinations are more sensitive to rice false smut:At the forth sowing time,32.00% of combinations middle resistant, but 16.00% of combinations are sensitive or high sensitive, and at the fifth sowing time, there is no combination with resistance, only one combination is middle resistant, however 64.00% of combinations are middle sensitive, and even 32.00% of combinations are sensitive. Therefore, just planted timely in the actual production, combinations ofrestorer line YaHui 2115 will not be seriously harmed from rice false smut. According to the data of initial heading stage and the meteorological data of 3-5days before initial heading stage, we come to aconclusion that the rainy weather later plays an important role in fluctuction of disease index of rice false smut on the combinations. |
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