Resistance Evaluation Of Different Rice Lines Response To Brown Planthopper And BPH Resistance Gene Mapping In 08BPH327

As a major pest in rice production, Brown planthopper (BPH) had brought immeasurable losses to rice yielding.At present, preventive measures to BPH primarily for the use of chemical pesticides. Howevef, due to the long-term use of chemical pesticides, causing the brown planthopper and their descendants mutation and even immunity to drugs.So finding resistant rice resources will be the main method of controlling BPH. In this study, different resistance evaluation methods were used to identify different rice varieties and then to study their resistance mechanisms. Besides, a new BPH resistance gene had been excavated from the Oryza rufipogon in our laboratory,and had been located at rice chromosome 4, the physical distance is about 16.0cM and between marker Ym61 and Ym54 of 70Kb region.To verify the accuracy of the positioning of the gene and provide research foundation for the subsequent fine mapping and cloning, in this study, we constructed a new mapping popullation then identified it and located it again, use the extreme recessive plants method for preliminary localization of the resistance gene.The main founding we summarized as follows:1.We evaluate the resistance of rice varieties Mudgo、ASD7、Rathu Heenati、Babawee、ARC10550、Swarnalata、T12、Chin Saba、Pokkali、 08BPH327、PTB33 and OB677、ARC5984、BPH660. TN1 in seedling and adult stages, respectively. And test the varieties for parameters of honeydew, growth rate, mortality rate, emergence rate and population density to perform the difference of their resistance to the BPH. The result showed that of the 15 rice varieties tested 13 presented not any or little difference in BPH resistance between seedling test and adult stage, while the other two varieties, T12 and OB677, were susceptible in seedling stage and moderate resistance in adult stage. The study on rice resistance mechanism showed that rice antixenosis to the BPH is usually not consistent with its resistance, but rice antibiosis to the insect is highly consistent with its resistance. It is concluded that rice varieties presenting resistance in seedling stage must resist in adult stage to the BPH, while some resistant varieties are susceptible in seedling stage and only present certain resistance adult stage. Therefore, seedling stage is a stage for reliable, efficient, simple and rapid screening for the BPH resistance. The antibiosis is dominant in rice resistance mechanisms,and it can reflect the rice resistance whether it is strong or weak.2.Use the variety of rice 08BPH327 which contain the new resistance gene to cross and backcross with rice 9311 (very sensitive to BPH),then had the mapping populations BC2F2. We screened the populations with BPH infestation,segregating 402 high resistance plants from the 1562 plants of the BC2F2,and then located the resistance gene at rice chromosome 4,between the SSR markers RM 16720 and RM 16794 about 2.4Mb region.