两种磷水平下玉米苗期根系性状的QTL定位

以耐低磷性状具有明显差异的玉米自交系X178和9782为亲本构建的重组自交系为研究材料,在正常供磷与低磷胁迫下对玉米苗期根系和地上部分干重等性状进行表型鉴定和QTL定位分析。结果表明,低磷胁迫下重组自交系地上部分干重下降最多,显示低磷胁迫下玉米苗期优先确保根系生长发育。两种磷水平下共检测到9个性状的16个QTL,主要位于第1染色体上,其中,正常磷水平下富集了5个QTL的bin1.06区域、低磷胁迫下集中了3个QTL的bin1.03区域可能是含有控制根系或磷利用相关性状基因的重要染色体区域。在定位的16个QTL中,位于第7染色体的根冠比QTLqRRS7_LP可解释表型贡献率高达14.06%,且增效等位基因来源耐低磷亲本X178,表明若对该位点进行分子标记辅助选择,可能会对耐低磷性状改良具有明显的选择效果。

QTL Mapping for Root Traits of Maize Seedling Grown at Two Phosphorus Levels

A recombinant inbred line population, developed from maize inbred line X178 and 9782 with distinct difference of phosphorus utilization, was used to identify phenotype variation and QTL for root traits of maize seedling under normal(CK) and low phosphorus(LP) application in sand culture. The results showed that shoot dry weight(SDW) among all root traits decreased most under phosphorus, which implied nutrition was preferentially used to ensure root development for maize seedling. A total of 16 QTL for 9 traits were detected for two treatments, most of which located on chromosome 1. Of these QTL information, chromosome region bin1.06 containing five QTL under CK, chromosome bin1.03 containing three QTL under LP were potentially important candidate chromosome region or target QTL for root traits or phosphorus utilization. In positioned 16 QTL, the explaining phenotypic variation of one QTL for root and shoot(qRRS7_LP) that on chromosome 7 was 14.06%, and synergism alleles originated from low-phosphorus parent X178, indicated that if molecular marker-assisted selection on the loci, could has the obvious choice effect to the improvement of low P tolerance characters.