Beinhart1000-1抗赤星病基因的QTL定位

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

为探索Beinhart1000-1的赤星病抗性遗传规律,以抗赤星病品种Beinhart1000-1为母本,感病品种G140为父本,构建F1及F2代群体,筛选与抗性基因紧密连锁的SSR标记,并进行抗性基因的QTL定位。结果表明,Beinhart1000-1的赤星病抗性由显性基因控制。同时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,利用该83对引物进行扩增,经WinQTLCart2.5分析,构建了83个标记的遗传连锁图谱,获得2个抗赤星病QTL位点,分别位于7号和15号连锁群上。

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