Application Of Molecular Marker-assisted Selection Of Improved Rice Blast, Brown Planthopper Resistance

Rice is the most important cereal crop, which provides stable food for about half of the global population. Rice blast disease, caused by fungal pathogen, Pyriculari grisea Sacc, is one of the most serious diseases of rice worldwide. The brown planthopper (BPH), Nilaparavata lugens, is one of the most serious insect pests of rice. Breeding resistant varieties has been proved to be one of the most effective and economical methods to control the rice disease and pests. The objectives of the study were to improve the resistance of Zhenshan97(ZS97) to rice blast disease by pyramiding Pil and Pi2 genes, and the resistance of Minghui 63(MH63) and ZS97 to the brown planthopper by pyramiding Qbpl and Qbp2 genes using molecular marker-assisted selection. The main results are as follows:1. Resistance of the molecular marker recombined lines showed that the Pil gene is located on the top of chromosome 11 between markers RM224 and RM144.2. The BCsFs lines of ZS97/BL6 were identified the resistance to the leaf blast and neck blast. The results showed that there were no significant difference among the resistant scores of the leaf blast of ZS97(?/7)> ZS97(P/2) and ZS97(P/7 > Pi2), which were l.CK 2.(k 2.0 respectively. But to neck blast, the resistant score of ZS97(Pil^ Pi2), which was 1.0 , was significantly higher than that of ZS97(P/7) and ZS97(/J/2), which both were 1.0. It showed that the genes pyramiding can improve the rice resistance to the blast disease, especially to neck blast.3. The SSR markers were founded. Qbpl gene was located in the region of markers MRG2329^ MRG2346> MRG2684 and MRG5949. Qbp2 gene was located in the region of markers MRG4319> RM261. So the MAS system based PCR marker was established.4. The resistant score to BPH showed that Qbpl and Qbp2 genes had significant effects on rice resistance to BPH and genes pyramiding can remarkably improve the resistance of MH63 to BPH.5. The BC3F3 lines of ZS97/B5 were identified the resistance to BPH . The resistant scores of ZS97(Qbpl), ZS97(Qbp2) and ZS97(Qbpl > Qbp2) were 3.1 > 4.4 and 4.2 respectively. The resistant score of ZS97(Qbpl^ Qbpl), was significantly higher than that ofZS97(Qbpl) and ZS97(Qbp2).