| Abstract |
Rice blast (BL) caused by Magnaporthe oryzae is a fungal disease causing significant yield
losses in rice production worldwide. To overcome the breakdown of resistance by the rapid adaptation
of pathogens, identifying resistance (R) genes or QTLs in indigenous rice, which harbors the R genes
that co-evolved with the local pathogen race, is necessary. In this study, a recombinant inbred line (RIL)
population derived from a cross between RD6 and Phaladum (PLD) was used to map quantitative
trait loci (QTL) for BL resistance through a QTL-seq approach. A single QTL (qBLchr4) associated
with BL resistance at the seedling and maximum tillering stages was mapped on the long arm of
chromosome 4. Five genes, LOC_Os04g0616600, LOC_Os04g0617900 (OsGLP4-1), LOC_Os04g0619600
(OsRLCK161), LOC_Os04g0620800 (Pi63), and LOC_Os04g0621500, were considered the candidate
genes representing qBLchr4. Subsequently, the Kompetitive Allele-Specific PCR (KASP) markers
specific for the SNP variant and position of each gene were designed for validation in the mapping
population. These markers showed the high phenotypic variance explained (PVE) values in all testing
methods and/or environments, signifying the major effect of qBLchr4. Among these markers, the
Pi63-KASP marker explained the highest and most stable phenotypic variation across all testing
methods and/or environments, with 84.18%, 80.34%, and 23.43% in the upland short row (USR)
method, Sila environment, and Mueang environment, respectively. Therefore, Pi63 was suggested to
be the strongest candidate gene. These results represent the potential utility of future BL resistance
breeding and/or pyramiding using marker-assisted selection (MAS).
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Publication
Journal Publication
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