The southern root-knot nematode, Meloidogyne incognita, is a pest that decreases yield and the quality of sweetpotato [Ipomoea batatas (L.) Lam.]. There is a demand to produce resistant cultivars and develop DNA markers to select this trait. However, sweetpotato is hexaploid, highly heterozygous, and has an enormous genome (∼3 Gb), which makes genetic linkage analysis difficult. In this study, a high-density linkage map was constructed based on retrotransposon insertion polymorphism, simple sequence repeat, and single nucleotide polymorphism markers. The markers were developed using F1 progeny between J-Red, which exhibits resistance to multiple races of M. incognita, and Choshu, which is susceptible to multiple races of such pest. Quantitative trait locus (QTL) analysis and a genome-wide association study detected highly effective QTLs for resistance against three races, namely, SP1, SP4, and SP6-1, in the Ib01-6 J-Red linkage group. A polymerase chain reaction marker that can identify genotypes based on single nucleotide polymorphisms located in this QTL region can discriminate resistance from susceptibility in the F1 progeny at a rate of 70%. Thus, this marker could be helpful in selecting sweetpotato cultivars that are resistant to multiple races of M. incognita.

中文翻译：

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通过在甘薯中进行定量性状基因座分析和全基因组关联研究，开发与南方根结线虫抗性相关的分子标记。

南部的根结线虫是根结线虫（Meloidogyne incognita），是一种害虫，会降低马铃薯的产量和品质（番薯）需要产生抗性品种并开发DNA标记以选择该性状。然而，甘薯是六倍体，高度杂合，并且具有巨大的基因组（〜3 Gb），这使得遗传连锁分析变得困难。在这项研究中，根据反转录转座子插入多态性，简单的序列重复和单核苷酸多态性标记构建了高密度连锁图谱。使用F1子代在J-Red和Choshu之间开发出F1代，J-Red对M. incognita的多个种都表现出抗性，而Choshu对这种害虫的多个种属很敏感。数量性状基因座（QTL）分析和全基因组关联研究在Ib01-6 J-Red连锁组中检测到对三个种族（即SP1，SP4和SP6-1）具有抗性的高效QTL。可以基于位于此QTL区的单核苷酸多态性鉴定基因型的聚合酶链反应标记物，可以以70％的比率将抗性与F1子代的敏感性区分开。因此，该标记可能有助于选择对多种隐杆线虫有抗性的甘薯品种。