Pi35(t), a new gene conferring partial resistance to leaf blast in the rice cultivar Hokkai 188.
The japonica rice cultivar Hokkai 188 shows a high level of partial resistance to leaf blast. For mapping genes conferring the resistance, a set of 190 F2 progeny/F3 families was developed from the cross between the indica rice cultivar Danghang-Shali, with a low level of partial resistance, and Hokkai 188. Partial resistance to leaf blast in the F3 families was assessed in upland nurseries. From a primary microsatellite (SSR) linkage map and QTL analysis using a subset of 126 F2 progeny/F3 families randomly selected from the above set, one major QTL located on chromosome 1 was detected in the vicinity of SSR marker RM1216. This QTL was responsible for 69.4% of the phenotypic variation, and Hokkai 188 contributed the resistance allele. Segregation analysis in the F3 families for partial resistance to leaf blast was in agreement with the existence of a major gene, and the gene was designated as Pi35(t). Another QTL detected on chromosome 8 was minor, explained 13.4% of the phenotypic variation, and an allele of Danghang-Shali increased the level of resistance in this QTL. Additional SSR markers of the targeted Pi35(t) region were further surveyed in the 190 F2 plants, and Pi35(t) was placed in a 3.5-cM interval flanked by markers RM1216 and RM1003.
Nguyen
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TT
Fungal Disease Laboratory, Department of Plant Pathology, National Agricultural Research Organization, Kannondai 3-1-1, Tsukuba, Ibaraki 305-8666, Japan.
Koizumi
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La
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TN
Zenbayashi
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KS
Ashizawa
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T
Yasuda
N
N
Imazaki
I
I
Miyasaka
A
A
D001203:Ascomycota / Q000502:physiology; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D017343:Genes, Plant; D008040:Genetic Linkage; D007113:Immunity, Innate / Q000235:genetics; D018895:Microsatellite Repeats; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D010375:Pedigree; D010935:Plant Diseases / Q000235:genetics*; D011110:Polymorphism, Genetic; D040641:Quantitative Trait Loci