油葵苗期抗旱相关性状的QTL定位及候选基因筛选

干旱是限制向日葵生长发育的重要因素之一。为探究向日葵苗期抗旱性分子机制，该研究以向日葵K55与K58杂交构建的150个F₇重组自交系群体为材料，对其在正常浇水和干旱胁迫两种水分处理条件下的叶片相对电导率、叶绿素含量、叶面积、叶片相对含水量、根长进行表型测定，利用前期建立的SNP、SSR分子标记遗传连锁图谱，通过复合区间作图法对5个抗旱相关的性状进行QTL定位。结果表明：(1)共定位到向日葵QTL位点11个，其中正常浇水条件下5个，干旱胁迫条件下6个，表型贡献率为0.768%~7.547%，且5号连锁群上定位到的QTL位点最多(3个)。(2)QTL置信区间内共筛选到62个与干旱相关的候选基因，包括位于qLA 8 1上的rna23019、rna23004、rna22661、rna22193、rna23294、rna22783和位于qCC 13 1上的rna40140，这些基因可作为后续基因克隆及功能研究的重点候选基因。该研究结果为向日葵抗旱性研究及其遗传改良奠定了基础。

QTL Mapping and Candidate Gene Screening of Drought Resistance related Traits in Oil sunflower Seedlings

Drought is one of the important factors limiting the growth and development of sunflowers. To investigate the molecular mechanism of drought resistance in sunflower seedlings, in this study, we used 150 F₇ recombinant self incompatible line populations constructed by crossing K55 and K58 as materials, and phenotypically determined the relative leaf conductivity, chlorophyll content, leaf area, relative leaf water content, and root length under two water treatment conditions of normal watering and drought stress. With the previous established genetic linkage maps of SNP and SSR markers we located five drought related traits by the composite interval mapping method. The results showed that: (1) a total of 11 QTL loci were localized, 5 under normal irrigation conditions and 6 under drought stress conditions, with phenotypic contributions ranging from 0.768% to 7.547%. 3 QTL loci were localized on Chr. 5, with the most loci. (2) 62 drought related candidate genes were screened within the QTL confidence interval, including rna23019, rna23004, rna22661, rna22193, rna23294, rna22783 on qLA 8 1 and rna40140 on qCC 13 1, which can be used as subsequent gene cloning and functional analysis. This study lays the foundation for drought resistance research and its genetic improvement in sunflowers.