Resistance QTLs controlling leaf and neck blast disease identified in a doubled haploid rice population

Abstract

One of the biotic constraints in rice production worldwide is blast disease which can control by planting resistant varieties. To find out effective resistance, blast resistance quantitative trait loci (QTL) were mapped against 20 and 3 virulent isolates for leaf blast and neck blast, respectively, using 111 doubled haploid lines from the cross of IR64 and Azucena. QTLs associated with leaf blast were found on chromosomes 1, 2, 4, 7, 8, 10, 11, and 12 (%R2 = 3.6 – 64.3), while neck blast linked QTLs were identified on chromosomes 1, 6, 10, and 12 (%R2 = 6.4 – 22.6). The new QTLs were identified on chromosome 1; however, most QTLs were mapped in the vicinity of resistance genes in previous references. The genetic relationship of leaf and neck blast was explained by the coincidence of detected QTLs and positive value of pathogenicity correlation (r = 4.5 – 4.7). This study provides reliable QTLs locations that will benefit rice breeding programs to develop new cultivars containing durable and broad-spectrum resistance to leaf and neck blast disease.