利用QTL-seq定位番茄果实质量QTL

Identification of Quantitative Trait Loci Controlling Tomato Fruit Weight by QTL-seq

为了分析樱桃番茄‘VFNT Cherry’(syn.LA1221)和加工番茄‘Heinz1706’组配的F1代果实质量超亲杂种优势的遗传基础,利用其F2群体,通过QTL-seq和单标记分析法进行了果实质量QTL定位,共检测到10个果实质量位点,其中8个位点的大果等位基因为显性,包括部分显性位点5个[QTL for Fruit Weight 2.1(qFW2.1)、qFW5.2、qFW7.1、qFW8.1、qFW9.1]和超显性位点3个(qFW1.1、qFW5.1、qFW6.1)。而且qFW2.1、qFW5.1、qFW7.1、qFW8.1、qFW9.1的大果等位基因来自‘Heinz1706’,qFW1.1、qFW5.2、qFW6.1的大果等位基因来自‘VFNTCherry’。因此F1代番茄果实质量出现超亲现象可能是由于其聚合了来自双亲的显性大果等位基因。上述8个显性位点中qFW9.1的表型变异贡献率最高,达到12.19%。通过交换单株后代鉴定进一步验证了qFW9.1位点并将其定位区间缩小到4.5 Mb。

The fruit weight of F1 generation derived from the cross between cherry tomato‘VFNT Cherry’(syn.LA1221)and processed tomato‘Heinz1706’was over parents,showing obvious heterosis.In order to analyze the genetic basis of this phenomenon,using F2 population obtained from the above F1 generation self-crossing,the QTL mapping of tomato fruit weight was carried out by QTL-seq and single marker analysis.A total of ten fruit weight QTLs were identified,and eight of which were dominant.Among the eight dominant QTLs,five QTLs were incomplete dominant[QTL for Fruit Weight 2.1(qFW2.1),qFW5.2,qFW7.1,qFW8.1,qFW9.1],and three QTLs were over-dominant[qFW1.1,qFW5.1,qFW6.1].Moreover,the big fruit alleles of qFW2.1,qFW5.1,qFW7.1,qFW8.1,and qFW9.1 were from‘Heinz1706’,and the big fruit alleles of qFW1.1,qFW5.2,qFW6.1 were from‘VFNT Cherry’.Therefore,the heterosis of tomato fruit weight in the above F1 generation may be due to its aggregation of dominant large fruit alleles from both parents.Among the eight dominant QTLs,qFW9.1 had the highest contribution rate of phenotypic variation,reaching 12.19%.The qFW9.1 locus was further validated and narrowed to a 4.5 megabase pair by recombinant progeny testing.