Identification of stably expressed QTL for resistance to black shank disease in tobacco ( Nicotiana tabacum L.) line Beinhart 1000-1

Abstract Cigar line Beinhart 1000-1 has effective durable resistance to black shank (BS) and is considered one of the most resistant sources in tobacco ( Nicotiana tabacum L.). To investigate the inheritance and identification of stable quantitative trait loci (QTL) for BS response, F 2 , BC 1 F 2 individuals and BC 1 F 2:3 lines were produced from a cross between Beinhart 1000-1 and Xiaohuangjin 1025. Two major quantitative trait loci (M-QTL) named qBS7 and qBS17 were repeatedly detected under different conditions. QTL qBS7 was mapped to the region between PT30174 and PT60621 and explained 17.40%–25.60% of the phenotypic variance under different conditions. The other QTL qBS17 in interval PT61564–PT61538 of linkage group 17 was detected in a BC 1 F 2 population in the field and in BC 1 F 2:3 in both the field and at the seedling stage, explaining 6.90% to 11.60% of the phenotypic variance. The results improve our understanding of the inheritance of resistance to BS and provide information that can be used in marker-assisted breeding.