Study On The Identification And Characterization Of Durable Blast Resistance Source In Rice

Rice blast, caused by Magnaporthe grisea (Hebert) Barr., is the most devastating fungal disease in the world, and has important effect on the yields. It has been proved that breeding and planting disease-resistant cultivars is the most economical and efficient means to control this disease. Screening and utilization of rice resources resistant to blast is the foundational measure to breed resistant varieties.Investigation on agronomic characters about rice materials from Institute of plant protection, Sichuan academy of agricultural science was made. The resistance, resistance spectrum and resistance gene analog techniques were studied for some important rice material in order to reconstruct rice resources and to breed disease-resistant varieties of rice. The main results of this study are as follows.1. Rice from the 770 rice materials selected 80 better resistance to the anti-source materials for the field and indoor of statistics and data types. Statistic and analysis about 80 rice materials agronomic characters was made. The result of correlation analysis about the blast resistance with agronomic characters of 80 tested rice material indicated that correlation coefficient did not achieve prominence level. Maybe resistance does not only judged by agronomic characters.2. Investigate on blast resistance disease level about 20 tested rice materials in different ecological zones. The result show that resistance of 20 tested rice material no difference in evidence. Leaf and neck blast resistance of R710 and R707 were higher than other material, no prominent difference with each other.3. The result of resistance spectrum indicated that Simiao-1, IR60937-40-3-1-3(89) were to 100%, of which resistance spectrum were wide. Gumei-1, Gumei-2, Gumei-3, Gumei-4, Gumei-5 that have been bred by Institute of plant protection, Sichuan academy of agricultural science in 1982, of which spectrum were 92.31%, 89.74%, 84.62%, 94.87%, 89.74%. Correlation analysis showed that resistance spectrum had negative relation with leaf and neck blast resistance disease level. In another word, leaf and neck blast resistance disease level higher as resistance spectrum lower.4. Five pairs of primer, RGAl(XLRR-for/XLRR-rev),RGA2(XLRR-invl/XLRR-inv2), RGA3(NLRR-for/NLRR-rev), RGA4 (Pto-kin1/Pto-kin2), RGA5 (S1/AS1) designed and synthesized according to the conserved domains of plant resistance gene were used for analyzing RGA-PCR of the 37 rice material, including 20 resistance resources and 17 Single genetic rice material. The result showed that RGA banding patterns produced by the five primers revealed a high level of polymorphism. Clustering analysis showed that the 20 rice materials could be classified into 6 groups by five pair primers combinations at 0.72 similarity coefficients. The dominant lineage were lineage III, including 6 rice materials, occupy with 30.00%. RGA-PCR maps of single genetic rice material amplified by RGA2 show 4 special bands around of 600bp, 150bp, 400bp, 320bp, and RGA1 show one special bands around 300bp. The five special fragments were retrieved and re-amplified, acquired relevant bands in RGA-PCR maps clearly. Finally, the strategies of improvement and utilization of rice resistance resources were also discussed.