胡麻成株期抗旱性紧密相关性状选择及QTL分析

Abstract: Oil flax is very important oil crops in arid areas of the Northern in China. The most important fact is the drought to result in low and unstable yield of oil flax. To achieve high and stable yield of oil flax, to explore drought resistance resource, illustrate mechanism of drought resistance, improve variety and increase drought resistance and water use efficiency are important significance in oil flax production. There is shortage on research of drought resistance of oil flax include domestic and international. On the basis of drought resistance evaluation of the early stage of the germplasm of the present project to establish nature population of rich phenotype and genotype and screen indicates on drought resistance in oil flax from budding stage to anthesis stage. By building specific population on RIL (Dingya 17 × Tianya 3) and utilizing technical simplication of genomic sequencing to explore SNP of a quantity and good polymorphism. The objective of present project to establish genetic linkage map of oil flax, establish efficient linkage analysis, position control QTL locus or point of drought resistance and clarify amount, origin, characteristic of distribution, function and values in use in resistance resource of allelic variation. There is highly significance on research results to screen drought resistance germplasm and gene and use maker-assisted selection for breeding in oil flax.

胡麻（Linum usitatissimum）是我国北方干旱地区主要油料作物。干旱是造成胡麻产量低而不稳的最主要因素，因此，发掘抗旱资源，阐明抗旱机理，改良品种,提高胡麻抗旱性和水分利用效率,实现丰产稳产,对胡麻生产具有重要意义，但是国内外胡麻相关抗旱研究十分缺乏。本项目在前期种质抗旱性鉴定的基础上，组建表现型和基因型丰富的自然群体，筛选与成株期抗旱密切相关的指标；通过构建特定的RIL群体(定亚17号×天亚3号)，利用简化基因组测序（SLAF-seq）技术，开发大量、多态性好的SNP标记，构建胡麻分子遗传连锁图谱，建立有效的连锁分析，定位控制抗旱性的QTL位点或区间，阐明其等位变异在抗旱资源中的数目、来源、分布特点、功能及利用价值。相关研究结果对筛选抗旱种质、发掘抗旱基因并进行分子标记辅助育种具有重要意义。

胡麻成株期指现蕾期至开花期，这一时期是生长发育的关键时期，干旱胁迫对植株发育和产量具有重要影响。在前期研究工作的基础上，本项目主要开展了2个关联RIL群体及高代材料抗旱指标筛选、抗旱性的表型鉴定、抗旱评价研究，结合构建的高密度遗传图谱，对重要农艺性状和抗旱性进行QTL定位分析。.利用GBS高通量测序技术对亲本和RIL群体株系进行深度测序，通过对SNP基因型分型后构建了两张遗传图谱。利用两张遗传图谱上共同的SNP标记将图谱进行整合，最终得到一张包含15个连锁群，共有4497个SNP标记的高密度遗传连锁图谱。此外，对两个RIL群体控制株高和工艺长度的QTL进行定位，分别得到了19个和9个QTL，对两个群体的QTLs和候选基因信息进行比较分析，发现了2个共同的QTLs和3个共同候选基因。.结合2017年和2018年表型结果，R4群体的加权抗旱系数（Cdrc）2018年性状共检测到3个QTL，分布在LG5，LG9连锁群上，能解释表型变异的0.7-08%；平均抗旱系数（Adrc）共检测到5个QTL，分布在LG4，LG5，LG12，LG13四个连锁群上。R6群体的2018年性状Cdrc共检测到1个QTL，分布在LG7连锁群上，能解释表型变异的0.4%；Adrc共检测到2个QTL，分布在LG7连锁群上。.