基于高通量测序的橡胶树高密度遗传图谱构建

Rubber tree is an important tropical crop in China. Nowadays the production of nature rubber is less than 20% of the consumption in China. It is time to breed more and more rubber clones with high yield and abiotic stress tolerance, but it is about 30 years to breed a rubber clone because rubber tree is heterozygous, long life cycle, and producing latex after plated for 6-8 years. So we need shorten the breeding time by molecular breeding. The high-density linkage map is the basis of molecular breeding, otherwise there isn't a high-density genetic map in rubber tree. In this study, we constructed a Reken192×Reken628 F1 population, and the population was sequenced by next-generation sequencing. SNPs were identified genome-widely in the parents and progeny, and the genetic map was constructed by JoinMap4.0 software based on polymorphic SNPs. The construction of high-density map is useful to QTL mapping, development of linkage markers, gene map-based cloning and so on, and can accelerate the development of rubber tree molecular breeding, thus the combination of traditional and molecular breeding will improve the breeding efficiency and achieve directed breeding in rubber tree.

目前我国天然橡胶的自给率已不足20%，天然橡胶种植业面临强大的增产压力，由于我国是非传统植胶区，因此需要培育更多地高产高抗品种。受橡胶树自身生物学特性诸如遗传背景复杂，生长周期长，6-8龄才可以开割产胶等的限制，传统育种方法要用近30年才能培育一个品种，远不能满足生产对品种的需求，必须借助分子育种手段缩短育种周期。高密度的遗传图谱是分子育种的基础，而橡胶树中现有的遗传图谱密度都较低。本研究利用高通量测序技术在橡胶树热垦192×热垦628的F1群体中发掘单核酸多态性（SNPs）标记，并构建基于SNPs的高密度遗传图谱，为橡胶树QTL定位、性状连锁标记开发及重要基因图位克隆等研究奠定基础，从而促进橡胶树分子辅助育种的发展，形成传统育种与分子辅助育种相结合的现代育种技术，缩短育种周期，最终实现橡胶树品种的快速定向培育。

橡胶树是我国热区种植的一种重要经济作物，而由于橡胶树是多年生高大乔木，生长周期长，传统育种方法要用近30 年才能培育一个品种，远不能满足生产对品种的需求，开展分子辅助育种研究有助于提高我国橡胶树育种的效率。高密度的遗传图谱是开展分子辅助育种的重要基础，目前我国在这方面的研究还比较欠缺。本项目主要以橡胶树热研8-79×野生种质88的F1群体为研究对象，采用简化基因组测序的方法对双亲热研8-79和野生种质88及205株F1子代进行了测序，亲本的测序深度为22×，子代的平均测序深度为6×，经过对标记的多次过滤后，最终获得上图标记数为 4543个，所构建的遗传图谱包括18个连锁群，总图距为2670.27cM，平均图距0.59 cM。该图谱是目前已报道的橡胶树遗传图谱中标记最多，密度最高的，也是我国首张橡胶树高密度遗传图谱。该图谱的构建，为今后开展橡胶树产量等性状相关标记QTL定位及橡胶树分子标记辅助育种研究奠定了良好的基础，有助于促进我国橡胶树遗传育种研究的发展。