벼 도열병 저항성 유전자 Pi45(t)의 균계 특이적 반응과 고밀도지도 작성

Mapping and Race Specific Reaction of the Resistance Gene Pi45(t) in Rice

QTL analysis for blast resistance was carried out using 140 BC 3 F 3 lines derived from a cross between Ilpum as a recurrent parent and Moroberekan as a donor parent. 140 BC 3 F 3 lines with the parents were inoculated with nine blast isolates. To identify QTLs for resistance to nine blast isolates, 134 SSR markers showing polymorphisms between the parents were genotyped for the 140 BC 3 F 3 lines. A total of 17 resistance QTLs to nine isolates were detected on chromosomes 2, 3, 4, 6, 7, 9 and 10. The phenotypic variance explained by each QTL ranged from 8.2% to 26.4%. The Moroberekan alleles contributed the positive effect at these 17 QTL loci. In a previous study, the QTL, Pi45(t) for durable resistance to blast was identified using a sequential planting method. To know the relationship between Pi45(t) and the isolate-specific resistance gene, an F 2 population was developed from a cross between Ilpum and an introgression line harboring Pi45(t). F 3 lines segregating for the Pi45(t) were inoculated to three isolates. F 3 lines from the F 2 plants with the Moroberekan segment at the target region showed resistance to two isolates. This result seems to indicate that the Pi45(t) and the isolate-specific resistance gene are tightly linked or the resistance is controlled by the same gene(s). The markers linked to genes controlling blast resistance would be useful in developing blast resistance lines in the breeding program.