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Characterization of Rice Blast Resistance Gene Pi61(t) in Rice Germplasm
- Ma, Jianbing, Jia, M. H., Jia, Y.
- Plant disease 2014 v.98 no.9 pp. 1200
- Magnaporthe oryzae, alleles, blast disease, chromosome mapping, cultivars, disease resistance, genetic markers, germplasm, greenhouses, heterozygosity, inbred lines, microsatellite repeats, quantitative trait loci, races, rice, United States
- Identification of resistance (R) genes to races of Magnaporthe oryzae in rice (Oryza sativa) germplasm is essential for the development of rice cultivars with long-lasting blast resistance. In the present study, one major quantitative trait locus, qPi93-3, was fine mapped using a recombinant inbred line (RIL), F₈ RIL171, derived from the cross between ‘Nipponbare’ and ‘93-11’. RIL171 contained a heterozygous qPi93-3 allele which was found to be resistant against nine U.S. common races—ID1, IA1, IB49, IE1, IA45, IB1, IC17, IB45, and IH1—of M. oryzae. An F₂ mapping population consisting of 2,381 individuals derived from RIL171 was evaluated with a field isolate (race) ARB82 (IA1) of M. oryzae under greenhouse conditions. Disease reaction of a resistant/susceptible ratio of 3:1 was identified with F₂:F₃ families. In total, 12 simple sequence repeat markers spanning qPi93-3 were used for fine mapping. Consequently, qPi93-3 was delimited to 4.2 Mb between RM3246 and RM7102. Three insertion-deletion (InDel) markers located between RM3246 and RM7102, that had previously used to map Pi61(t), showed that qPi93-3 was Pi61(t). The existence of Pi61(t) in 136 rice germplasm lines from the United States Department of Agriculture rice core collection was evaluated using Pi61(t)-specific InDel markers. Pi61(t) was identified as a source of resistance in 5 of the 136 lines. The characterized germplasm will be useful for rice breeders to use for improving blast resistance.