弱筋小麦宁麦9号及其衍生系的蛋白质含量遗传多样性及关联分析

摘要

优质弱筋专用小麦品种宁麦9号是江苏淮南麦区小麦育种的重要亲本，以其为亲本已育成15个新品种。研究宁麦9号遗传信息的传递特点及蛋白质含量的数量性状位点，对进一步利用其进行优质弱筋小麦育种具有重要意义。以宁麦9号及其117个衍生品种(系)为材料，利用覆盖小麦全基因组的185对 SSR 引物对其进行基因组扫描，解析宁麦9号遗传信息在其衍生品种(系)中的分布特点，同时于2009—2010、2010—2011连续2个生长季测定宁麦9号及其衍生品种(系)的籽粒及面粉蛋白质含量，应用全基因组关联作图发掘与其相关联的分子标记位点。结果显示，宁麦9号与其衍生品种(系)的遗传相似系数为0.55~0.88；在 Neighbor-Joining 聚类图中，大部分衍生一代品种首先与宁麦9号聚类，其次是衍生二代，衍生一代品种扬辐麦4号最后聚类。宁麦9号与其衍生一代和衍生二代相同等位变异频率分别为75.60%和67.81%。籽粒及面粉蛋白含量在宁麦9号衍生品种(系)中均呈现较大变异，变异系数为5.07%~7.28%。共检测到6个与籽粒蛋白质含量关联的标记位点，其中3个连续两年均检测到；面粉蛋白质含量共有5个关联位点，其中2个连续两年检测到，包括1个同时与籽粒和面粉蛋白质含量关联。在这4个稳定的关联位点中， Xgwm539、Xwmc397和 Xwmc468对籽粒及面粉蛋白质含量起负向调控作用，可以降低籽粒或面粉蛋白质含量。%Ningmai 9 is an elite weak gluten wheat cultivar and an important breeding parent in the southern area of Huai River Valley. To date, 15 new cultivars have been developed and released from Ningmai 9. This study aimed at dissecting the genetic mechanism and inheritance of protein content in Ningmai 9 and its derivatives. The kernel protein content (KPC) and flour protein content (FPC) of Ningmai 9 and its 117 derivatives were evaluated in the 2009–2010 and 2010–2011 growing seasons and the QTLs associated with KPC and FPC were identified by whole genomes screening with 185 SSR markers. The genetic similarity index ranged from 0.55 to 0.88 among Ningmai 9 and its derivatives. In the Neighbor-Joining cluster tree, Ningmai 9 was clus-tered with most first-generation lines first, then with the second-generation lines, and Yangfumai 4 of first-generation derivative was the last one to incorporate in. The first- and second-generation derivatives inherited 75.60% and 67.81% of Ningmai 9 alleles, respectively. Great variations of KPC and FPC were observed in the Ningmai 9 derived lines with the variation coefficients rang-ing from 5.07% to 7.28%. Six and five QTLs were identified to be associated with KPC and FPC, of which three and two were stably detected in both years, respectively. One QTL was associated with both KPC and FPC. Three stable QTLs, Xgwm539, Xwmc397, and Xwmc468, had negative effects on KPC or FPC in Ningmai 9 and might be used for quality improvement in weak-gluten wheat breeding.