Beinhart1000-1抗赤星病基因的QTL定位

为了研究赤星病抗性的遗传规律，筛选与抗性基因紧密连锁的SSR标记，并将抗性基因进行QTL定位，用抗赤星病品种Beinhart1000-1作母本，感病品种G140作父本，构建了F1及F2代群体，并对其进行了抗性鉴定和遗传分析。结果表明，Beinhart1000-1的赤星病抗病性是由显性多基因控制的。利用混合群体分组分析法，从2653对SSR引物中，得到83对在抗感池间表现多态且扩增条带稳定清晰的SSR标记。以F2代群体115个单株为作图群体，将该83对引物进行扩增，并用WinQTLCart2.5分析数据。这83个标记分别连锁到18个连锁群上，同时定位到两个抗赤星病的QTL位点，分别位于7号和15号连锁群上。 

Mapping of quantitative trait loci affecting resistance to brown spot in tobacco line Beinhart1000-1

To elucidate the genetic basis of resistance to brown spot in tobacco cigar line, Beinhart1000-1, and to identify the genomic locations contributing to the resistance, F1 and F2 populations were constructed from a cross between Beinhart1000-1 and susceptible variety, G140. The inheritance of resistance to brown spot was analyzed in F1 and F2 populations. It is shown that the resistance to brown spot of Beinhart1000-1 was controlled by the dominance genes. A population of 115 F2 was further used for QTL mapping of resistance to brown spot with 83 SSR markers. Two QTLs, named RBS-1 and RBS-2, are discovered on No.7 and 15 genetic linkage groups through composite interval mapping method, respectively. The major QTL, RSB-1, is flanked by the marker M935 with the genetic distance of 7.4 cM and accounts for 15.89% of the phenotypic variance. The other major QTL, RBS-2, is flanked by the marker M653 with the genetic distance of 9.8 cM and explained 14.42% of the phenotypic variance. These results could facilitate our understanding of the inheritance of resistance to brown spot in tobacco by marker-assisted selection.