薏苡高密度遗传连锁图谱构建与重要品质性状的QTL定位

Coix lacryma jobi L. is a traditional economic crop as drug and food with high nutritional and medicinal value. Cultivation of new varieties of Coix lacryma jobi L. with high yield and quality has become the major target as its genetic background was narrow, the species variety was single in the main plant area. For promoting the development of Coix lacryma jobi L. industry, specific molecular markers and mining excellent agronomic traits could be used as an effective way. In this project high throughput sequencing has been use for building high density linkage map of Coix lacryma jobi L. through SSR and SNP marker. Using the genetic linkage map and phenotypic data measured over many consecutive years, quantitative trait loci (QTL) analysis was conducted for thousand grain weight, amylopection contents, protein contents, grain type traits and secondary metabolite contents. It can be used for studying the QTL of important quanlity traits distribution character and regulation in molecular genetic maps of Coix lacryma jobi L.. Relationship between progeny growth performance and molecular marker-based genetic distances was evaluated. This provides a basis for understanding the genetic architecture of these important quanlity traits and for molecular Coix lacryma jobi L. breeding.

薏苡是传统药食兼用经济作物，具有极高的营养价值和药用价值。我国薏苡主栽区生产品种单一，开发特异薏苡分子标记是挖掘优良农艺性状的一种十分有效的途径。本项目借助于高通量测序技术开发大量SSR和SNP标记，构建了一张薏苡高密度遗传连锁图谱；在连续多年表型性状测定的基础上，对薏苡千粒重、支链淀粉、蛋白质含量、粒型及药用有效成分等性状进行了QTL分析，从而揭示薏苡重要农艺性状基因位点在分子遗传图谱中的分布特点和规律；并探讨了薏苡杂交亲本分子标记遗传距离与子代生长性状之间的关系。相关研究结果为在分子水平开展薏苡遗传改良工作奠定基础，对深刻理解薏苡重要品质性状的遗传机制具有重要意义。

薏苡是传统药食兼用经济作物，具有极高的营养价值和药用价值。贵州薏苡种植面积和产量居全国之首，已成为贵州特色优势产业和区域性支柱产业。我国薏苡主栽区生产品种遗传基础狭窄，主栽品种单一，培育高产优质薏苡新品种已成为今后薏苡产业发展亟待解决的问题。项目以开展了薏苡种质资源的表型和基因型多层次遗传多样性分析，初步探明薏苡资源遗传多样且表型变异与环境相关，弄清了其幼苗的农艺性状与抗旱性关联性，基于高通量测序技术，开发大量SSR和SNP标记，并构建了一个高密度薏苡连锁图谱。主要结果如下：1、薏苡资源表型变异与环境相关，且叶长、叶宽、茎粗、分枝数等表型特征表现出多样性。2、幼苗存活率、株高、叶宽、根长和根鲜重等农艺性状与抗旱性存在关联，明确了茎粗、根长和根鲜重是薏苡抗旱性的衡量指标。3、薏苡种质资源遗传多样性且表型变异与环境相关，整体表现为遗传基础较狭窄，可能由于标记在基因组上的分布具有偏好。4、基于高通量测序技术，开发了266985个SSR位点，包括171530个SSR独立位点和6220个复合型SSR位点；SSR发生频率为14.88%，SSR位点分布密度为1/6.49kb。5、“Y113”ד贵薏苡1号”为群体，构建了一个高密度薏苡连锁图谱，该图谱共10个连锁群，总距离1,620.39 cM，平均标记间的距离为0.45cM，挖掘出一批控制薏苡重要农艺性状的SNPs位点，以期为薏苡相关性状的基因克隆、分子标记辅助育种、功能基因组学等研究提供理论依据。