基于SNP遗传图谱定位盐、旱胁迫下甘蓝型油菜种子发芽率的QTL

研究盐胁迫、干旱胁迫下甘蓝型油菜的发芽率，寻找与发芽率相关联的分子标记，可为油菜逆境胁迫下种子萌发的分子标记辅助育种提供理论依据。本研究以甘蓝型黄籽油菜GH06和甘蓝型黑籽油菜P174为亲本，通过单粒传法(single seed descent, SSD)连续自交9代构建重组自交系群体。采用16 g L^–1的NaCl溶液进行盐胁迫，20% (W/W)的PEG-6000溶液模拟干旱胁迫，处理重组自交系种子并统计其发芽率。实验室构建的SNP遗传图谱，包含2795个SNP多态性标记位点，总长1832.9 cM，相邻标记间平均距离为0.66 cM，利用该图谱并采用复合区间作图法(CIM)分析两种胁迫条件下第3天、第4天及累计4 d后发芽率的QTL。共检测到19个QTL，分布于A01、A03、A06、A07、A09和C06染色体上。其中，11个盐胁迫相关的QTL可解释的变异为4.9%~10.9%，8个干旱胁迫相关的QTL可解释的变异为3.8%~6.9%；并且在A03和A09染色体上，盐胁迫和干旱胁迫下检测到的QTL有相近区段。研究结果表明油菜种子发芽率属于典型的数量性状，受环境影响较大；且随着胁迫时间的延长，油菜种子启动了不同的基因来响应环境胁迫。

Mappingof QTLs for OilseedGermination RateunderStresses of Salinity and Drought in Brassica napus L. Based on SNP Genetic Map

The objective of this study was to identify QTLs for seed germination percentage of Brassica napus under the salinity stress and drought stress using the composite interval mapping (CIM) method. The recombinant inbred lines (RIL) population derived from a cross between yellow-seeded female parent GH06 and black-seeded male parent P174 was established by selfing for nine successive generations with single seed propagating from F₂. The oilseeds were dealt with NaCl (16 g L^–1 solution) for salinity stress, 20% (W/W) PEG-6000 solution for drought stress. The QTLs of germination ratein two different stress conditions were detected using the SNP genetic map constructed in 2013, which contains 2795 SNP markers with the total map length of 1832.9 cM and an average distance of 0.66 cM. A total of 19 QTLs for seed germinationrate under two stresses were located onchromosomes of A01, A03, A06, A07, A09, and C06. Twelve QTLs related to salinity stress were detected, with explained phenotypic variation from 4.9% to 10.9% of, while eight QTLs related to drought stress were detected, with explained phenotypic variation from 3.8% to 6.9% of. Some QTLs located on A03 and A09 under two stresses were detected in a near region. In conclusion, (1) the seed germination percentage is a quantitative trait controlled by many minor-effect genes, and the expression of the QTL is affected by environmental factors greatly; (2) different genes are involved in the oilseed responses to the stresses of different stages.