甘蓝型油菜叶绿素含量与产量关系研究及叶绿素主效QTL位点cqSPDA2连锁标记开发

本研究前期以中双11（ZS11）作母本、QU作父本通过小孢子培养构建了一个包含282个株系的DH群体，并通过两环境表型考察及DH基因型分型，对甘蓝型油菜叶片叶绿素含量（SPAD值）进行分析和定位，在A2染色体21.87~22.91 Mb区间获得一个主效QTL，为了进一步明确甘蓝型油菜叶绿素含量与产量的关系，通过分子标记和KASP技术以ZS11作轮回亲本构建了叶绿素主效QTL单位点的近等基因系群体，基于DH群体和单位点近等基因系群体为研究材料，对苗期叶片叶绿素含量和产量性状的相关性进行了分析。结果表明：在西宁和互助两个环境中，DH群体叶片SPAD值呈正态分布，双亲SPAD值呈极显著差异，F₁的SPAD值呈偏高值分布，表明该性状为部分显性，且不同环境条件下，同一群体叶绿素的含量不同，高海拔和低温条件下SPAD偏高；在一定范围内，叶绿素SPAD值与单株产量正相关，且相关系数随样本量的减少而增加；单株产量在两组不同基因型近等基因系中均存在极显著性差异（P<0.01）。根据遗传连锁图置信区间，开发了2个多态性较好的共显性InDel标记和基于KASP技术的6个分型较好的SNP标记作为分子标记辅助选择育种筛选的候选标记。本研究为油菜高叶绿素性状的分子标记辅助选择提供了标记基础，为高光效新品种的选择提供了理论依据。

Relationship between chlorophyll content and yield and development of chlorophyll major QTL cqSPDA2 linkage marker in Brassica napus

In the early stage of this study, a DH population containing 282 lines was constructed by microspore culture with Zhongshuang 11 （ZS11） as female parent and QU as male parent. Through the investigation of two environmental phenotypes and DH genotyping, the chlorophyll content （SPAD value） of Brassica napus leaves was analyzed and located, and a main QTL was obtained in the range of A2 chromosome 21.87-22.91 Mb. In order to further clarify the relationship between chlorophyll content and yield of Brassica napus, the near isogenic line population constructed by chlorophyll major QTL with ZS11 as recurrent parent were used to determine SPAD value of leaves at seedling stage, and then the correlation between SPAD value of chlorophyll and yield per plant was analyzed. The results showed that：（1） the SPAD values of DH population were normally distributed in Xining and Huzhu, the parents' SPAD values were significantly different （P<0.01）, and the higher SPAD values of F₁ showed that the trait was partially dominant, and the chlorophyll content of the same population was different under different environmental conditions. Under the condition of high altitude and low temperature, chlorophyll content increased. （2） In a certain range, the increase of chlorophyll content was helpful to improve the yield of single plant, chlorophyll SPAD value was positively correlated with plant yield, and the correlation coefficient increased with the decrease of sample size. （3） There was significant difference in yield per plant between two groups of near isogenic lines with different genotypes （P<0.01）. （4） According to the confidence interval of genetic linkage map, two co-dominant InDel markers with good polymorphism and six SNP markers with good typing based on KASP technology were developed as candidate markers for molecular mark assisted breeding.