甘蓝型油菜氮肥利用效率的QTL定位及遗传效应解析

There existed significant difference of nitrogen use efficiency among rapeseed genotypes, cultivating high nitrogen use efficiency rapeseed varieties can improve the nitrogen use efficiency, reduce nitrogen fertilizer application, reduce the production cost of rapeseed and the risk of soil residual nitrogen pollution to the environment, and can achieve the purpose of nitrogen emissions reduction, has the dual effect of resource conservation and environmental protection. This study through use high nitrogen use efficiency rapeseed genotype "xiangyou 15" and low nitrogen use efficiency rapeseed genotypes "R210" as the parents to build the backcross generation and DH populations to proceed genetic analysis and QTL mapping, in order to make clear the genetic effects such as additive and dominant for nitrogen use efficiency, and make clear the nitrogen use efficiency related QTL and the distribution on the chromosome. Select key gene loci, proceed association analysis for DNA allelic variation associated with the nitrogen use efficiency in rapeseed EMS mutation groups, master these loci in different nitrogen fertilizer utilization degree of allelic variation among genotypes. Based on the genetic analysis of nitrogen use efficiency genotype difference, which can provide theoretical basis for breeding high nitrogen use efficiency rapeseed varieties. meanwhile, the high nitrogen use efficiency genotypes can be used as breeding material or directly used in rapeseed production.

甘蓝型油菜基因型间存在着显著的氮肥利用率差异，培育氮肥利用率高效的新品种可以提高氮肥利用率，减少氮肥用量，降低生产成本和土壤剩余氮肥对环境污染的风险，达到降氮减排的目的，具有节约资源和环保双重功效。本研究通过甘蓝型油菜氮肥高效利用基因型“湘油15”和低效基因型“R210”作为亲本构建的回交世代和DH群体进行数量遗传分析和QTL定位，以明确氮肥利用率的加性、显性等遗传效应和氮肥利用率相关的QTL数量及在染色体中的分布等遗传信息；并选择关键基因位点，在油菜EMS突变群体中进行DNA等位变异与氮肥利用率的关联分析，掌握这些基因位点在不同氮肥利用率基因型之间的等位变异程度。通过对氮肥利用率基因型差异的遗传效应解析，为油菜氮高效品种选育提供理论依据；同时，获得的氮肥利用率高效基因型可作为育种中间材料或直接用于油菜生产。

解析甘蓝型油菜氮肥利用效率遗传效应，培育氮肥高效利用新品种可以提高氮肥利用率，减少氮肥用量，具有节约资源和环保双重功效。通过项目实施，初步确定了油菜氮素吸收效率(NAE)主要受2对加性-显性-上位性主基因控制，氮素利用效率(NUE)主要受1对加性主基因+加性-显性多基因控制，氮收获指数(NHI)主要受2对加性-显性-上位性主基因+加性-显性-上位性多基因控制。构建了甘蓝型油菜19个连锁群的高密度遗传连锁图普，SNP标记共计4302个，总长度2959.89cM，平均图距0.69cM；共检测到14个QTL，分别位于A03、A07、A08、A09、A10、C02、C03、C04、C05、C09染色体上，单个QTL可解释表型变异的5.24%-18.22%；分别在A03、A08、A09、C02和C03染色体上的QTL区间内筛选到7个可能与油菜氮肥高效吸收相关性状的候选基因；获得BnNRT1.1、BnGRF4、BnNR2和BnTCP19 4个氮素代谢相关基因在氮高效油菜基因型的表达规律及调控明显的EMS诱变系。研究结果将有助于甘蓝型油菜氮肥利用效率功能基因挖掘和分子标记辅助选择，为油菜氮高效品种选育提供理论依据。