棉花“三桃”性状的QTL定位

棉花的"三桃"(伏前桃、伏桃和秋桃)一直以来被认为是棉花早熟高产的重要指标。文章以早熟高产棉百棉2号为核心亲本,分别与中晚熟材料TM-1和中棉所12杂交,获得两个组合的F2和F2:3家系群体。对两个组合进行了遗传连锁图谱构建,标记位点分别为269个和127个,图谱总长分别为1 837.8 cM和1 244.3 cM。两组合共检测到29个"三桃"性状QTL,包括16个可能性QTL和13个显著性QTL,其中,5个显著性QTL的LOD值既大于3又大于permutation阈值;16个QTL的贡献率大于10%,解释表型变异的10.9%～44.5%。在两组合的相同染色体共同标记附近检测到4个共同QTL,分别为伏前桃qPSB-17、伏桃qSB-17(qSB-17a/17b)和秋桃qAB-17、qAB-12/26,可用于棉花"三桃"性状的标记辅助选择;其中,伏桃qSB-17(qSB-17a/17b)在两个组合中的贡献率均大于10%,秋桃qAB-17、qAB-12/26在一个组合中的贡献率均大于10%,这些既共同又贡献率较大的QTL在标记辅助选择中应优先考虑。

QTL mapping for "pre-summer boll, summer boll and autumn boll" traits in cotton

"Pre-summer boll, summer boll and autumn boll" have long been regarded as an important index for prematurity and high-yield in cotton. In this study, the prematurity and high-yield cotton cultivar, Baimian 2, was used as the central parent to cross separately with the middle-late-matury lines TM-1 and CIR12, and then two populations of F2 and F2:3 family lines were obtained, which was used to construct two genetic linkage maps. These maps were comprised of 269 and 127 marker loci with the total length 1837.8 cM and 1244.3 cM, respectively. Results of QTL location showed that a total of 29 QTLs were detected in the two combinations, including 16 suggestive QTLs and 13 significant QTLs, of which 5 significant QTLs had higher LOD values that was not only greater than 3 but also greater than the threshold calculated by permutation test. The contribution rate of 16 QTLs explained 10.9%-44.5% of the phenotypic variations. Four common QTLs, qPSB-17 for pre-summer boll, qSB-17 (qSB-17a/17b) for summer boll, and qAB-17 and qAB-12/26 for autumn boll, were detected close to common markers of the same chromosome in the two combinations, which could be applied in marker-assisted selection. Moreover, the contribution rate of qSB-17 (qSB-17a/17b) for summer boll in the two combinations was greater than 10%, and that of qAB-17, qAB-12/26 for autumn boll in one combination were greater than 10%. These common QTLs with greater contribution rates should take into consideration firstly in marker-assisted selection.