QTL mapping for resistance to strip virus disease in rice

With 2 figures and 5 tables Abstract To discover new resistance genes to rice stripe virus disease (RSVD), quantitative trait loci (QTL) analysis was conducted by using 162 recombinant inbred lines, derived from a cross between ‘Guichao 2’ and ‘Koshihikari’, RSVD resistances were evaluated using both artificial inoculation and natural infection methods by scoring the ratio of the disease rating index. Three QTL-controlling RSVD resistance were detected by the above two methods, which located on chromosomes 4(qStv4), 9(qStv9) and 12(qStv12), respectively. The qStv9 and qStv12 was repeatedly detected in artificial inoculation test in 2006 and 2008. In natural inoculation test, the qStv4 and qStv9 was detected in 2006, and the qStv12 was detected in 2008. As qStv9 and qStv12 explained 11.3–32.1% of the resistance effect from ‘Guichao 2’ across two environments, they should be a useful genetic resource in rice MAS breeding programme against RSVD. Further analysis revealed that the lines harbouring the alleles of qStv9 and qStv12 exhibited significantly increased resistance to RSVD, implying the possibility of breeding new resistant varieties by pyramiding resistant QTL through marker-assisted selection.