玉米穗行数主效位点qKRN5.04精细定位与遗传效应解析

穗行数是影响玉米产量的重要因素之一,其遗传机制解析和关键基因精细定位对开展分子育种具有重要的意义。本研究以穗行数仅有4行的"四路糯系选"和多穗行自交系"农531"(18~22行)为亲本,构建了高代回交群体和次级定位群体(四路糯选系为供体亲本,农531为轮回亲本)。通过对不同类型试验群体的多环境表型鉴定和基因型鉴定,利用完备区间作图法(ICIM)进行穗行数主效QTL定位分析,将穗行数主效位点q KRN5.04定位到第5染色体136.3~140.0 Mb的区间之内;遗传效应分析发现,该位点在不同环境条件下最大可解释的表型变异为21.76%,效应值为0.80~1.76行。通过次级分离群体重组事件分析可将其进一步定位到~300 kb区间内。本研究结果不仅为分子标记辅助选择提供了实用的In Del标记,而且为玉米穗行数主效位点q KRN5.04的图位克隆和候选基因挖掘奠定了重要的基础。

Fine Mapping andGenetic Effect Analysis of qKRN5.04, a Major QTL Associated with Kernel Row Number

For kernel row number (KRN), one of the important factors of maize yield, the genetic basis dissection and fine mapping of crucial gene would be greatly beneficial to maize molecular breeding. In present study, series of advanced backcross population and secondary segregation population were developed from a backcross of the derived line of four-row waxy corn (four kernel rows, as the donor parent) and Nong531 (18-22 kernel rows, as the recurrent parent). The QTL mapping for KRN was conducted by the inclusive complete interval mapping (ICIM) method in multiple environments. And a major KRN QTL, qKRN5.04, was mapped to the interval of 136.3-140.0 Mb on chromosome 5, with the largest phenotypic variation of 21.76% and the effect value of 0.80-1.76 row. Furthermore, according to recombinant analysis of secondary population, qKRN5.04 was fine mapped to the region of about 300 kb, which provided both practical InDel markers for marker-assisted selection and sufficient supports for the map-based cloning and candidate gene mining of the target locus.