| DH population from IR64/Azucena, and RIL population from Zhenshan97B/Milyang46, with different genetic background, were used for studies on inheritance and gene mapping of blast resistance in rice. Several genes conferring blast resistance were mapped. Below are the major results.1. R64 is resistance to eight of the 20 rice blast isolates originating from Zhejiang province. ZB13 and ZB15 are prevailing races in Zhejiang province, IR64 showed medium resistance to one isolate of ZB13 (98-182) and one isolate of ZB15(21-1) with a score of 3, but susceptible to another isolate of ZB15(21-19) with score of 6. Azucena is susceptible to all above 20 isolates .2. Three genes were found conferring resistance to 4 rice blast isolates in IR64, designate Pi-irl, Pi-ir2, Pi~ir3, Each of these genes was found to confer resistance to at least two blast isolates but none to all four isolates. Pi-irl, Pi~ir2 & Pi-ir3 were mapped on chromosome 2% 8 & 12, located on fragment of RG95-RG123 (LOD=4. 70) , RAG8ARO-A10K250 ( LOD=4. 31) & AF6-RG341(LOD=7.52) respectively. Pi~ir3 is resistant to all three indica isolates 20-3(ZB29) , 21-25(ZC15) &98~182(ZB13); Pi-ir2 is resistance to one indica isolates 20-3(ZB29) and one japonica isolate 20-116(ZG1); Pi-irl is resistant to one japonica isolate 21-116(ZG1). Interval mapping identified three QTLs with resistance to an indica isolate 98-182(ZB13), Two QTLs for LSN(qLSN) and one for LSI (qLSI). Both qLSN-1 and qLSI were mapped on chromosome 12 between AF6-RG341 with LODs of 4. 86 and 7.03 respectively. qLSN-1 was mapped on chromosome 2 between RFLP markers RG95 and RG256 (LOD=2. 60). It was overlapped by the major blast resistance gene Pi-irl.3. By analysis of the resistance to isolate 98-182(ZB13) in the RIL population, one major resistance gene from Zhenshan97B designated Pi-zsand one from Milyang46 designated Pi-my were mapped on chromosome 1 between RFLPmarkers RZ460 and RZ730, 3. 8cM from RZ730, and on chromosome 12 between RG81 and RM313, 4.OcM from RG81.4. Comparison analysis of the two linkage map of the DH and RIL population, showed that Pi-ir3and Pi-my, located on the chromosome 12, might be the same gene. |
