紫花苜蓿粗灰分与矿质元素含量QTL定位分析

QTL Analysis of Ash and Mineral Elements in Alfalfa

为初步鉴定与紫花苜蓿(Medicago sativa)粗灰分、钾、钙、镁、磷含量调控相关的数量性状基因座(Quantitative trait loci,QTL)和分子标记,本研究用低产早熟苜蓿和高产晚熟苜蓿杂交,构建了由392个个体组成的F_(1)群体,对这些性状进行3年表型数据测定,且基于前期已构建的高密度遗传连锁图谱开展QTL定位。结果表明:共检测到63个与粗灰分和4种矿质元素含量相关的QTL,分布于22个染色体上,单个QTL的贡献率为2.50%~29.85%;其中重复定位的QTL共8个(qCa-3C-1和qCa-3C-2,qCa-6B-1和qCa-6B-2,qCa-6D-1和qCa-6D-2,qAsh-8B-1和qAsh-8B-2),共定位的QTL有6个(qP-2C和qK-2C,qP-3A和qMg-3A,qP-6D-3和qMg-6D-2);经进一步验证,与这些QTL紧密连锁的标记可用于分子标记辅助选择育种。本研究为选育矿质营养更丰富的苜蓿新品种奠定了基础。

The objective of this study was to identify quantitative trait loci(QTL)and molecular markers associated with the contents of ash,potassium,calcium,magnesium,and phosphorus in alfalfa(Medicago sativa).To understand the genetic basis of these traits,an F_(1) population that consisted of 392 individuals was developed by crossing a low-yielding precocious alfalfa genotype(male parent)with a high-yielding late-maturing alfalfa cultivar(female parent).The three-year phenotypic data were collected and QTL mapping was carried out based on the high-density genetic linkage map that had been constructed previously.The results showed that sixty-three QTLs associated with ash and four mineral elements were identified.Phenotypic variance explained by single QTL was 2.50%to 29.85%,which distributed on twenty-two linkage groups(chromosomes).Among those,eight QTLs were located at the same position repeatedly(qCa-3C-1 and qCa-3C-2,qCa-6B-1 and qCa-6B-2,qCa-6D-1 and qCa-6D-2,qAsh-8B-1 and qAsh-8B-2)and six QTLs were co-located(qP-2C and qK-2C,qP-3A and qMg-3A,qP-6D-3 and qMg-6D-2).With further validation,the markers closely linked with these QTLs may be used for marker-assisted selection in breeding new alfalfa varieties with high mineral elements.