玉米SSR连锁图谱构建及叶面积的QTL定位

叶片是玉米进行光合作用的主要器官,叶面积的大小(尤其是穗三叶面积)对于玉米干物质的积累及产量形成起着至关重要的作用。研究玉米叶面积的遗传基础对于指导玉米高产育种具有理论意义。文章以两个叶面积差异显著的亲本478×武312为基础材料所构建的218个F8代的重组自交系为作图群体,构建了一张包含184个SSR标记的遗传连锁图谱,图谱总长度为2084.1cM,平均图距为11.3cM。通过两年的田间试验对玉米叶面积(穗三叶)进行了QTL定位分析。两年共定位到7个和叶面积相关的QTL位点,2006年定位到4个QTL位点;2007年定位到3个QTL位点。在第2染色体umc1542-umc1518标记区间发现一个主效QTL位点,该位点可以在两年同时检测到,两年分别解释12.5%和17.3%的表型变异。该位点能稳定地检测到且具有较大的贡献率,可能会在玉米叶面积分子标记辅助选择上有所应用。

SSR linkage map construction and QTL mapping for leaf area in maize

Maize leaf is the main organ for photosynthesis. The area of leaves (especially the ear-leaf and the two leaves above and below the ear-leaf) plays a vital role in dry matter accumulation and grain yield. Therefore, genetic information about leaf area has a theoretical significance for breeding maize with high yield. In this study, a genetic linkage map composing 184 simple sequence repeat (SSR) markers was constructed based on an F8 recombinant inbred line (RIL) population, derived from a cross between 478 and W312. The parents show a significant differences in leaf area. The map covers 2084.1 cM with an average interval of 11.3 cM. QTLs for leaf area were identified under two-year’s field experiments. Totally 7 QTLs were detected in two years, among which 4 QTLs were detected in 2006 and 3 QTLs in 2007. A major QTL on chromosome 2 (between umc1542 and umc1518) were detected both in 2006 and 2007. It explains 12.5% and 17.3% of the phenotypic variation, respectively. This locus may be used as a potental marker for improving maize leaf growth through marker assisted selection (MAS) approach.