两种光、氮条件下玉米苗期根冠性状QTL定位

QTL Mapping of Root and Shoot Traits of Maize Seedlings under Different Light and Nitrogen Conditions

以根、冠性状差异显著的亲本478和Wu312为基础材料,构建了含218个株系的F8重组自交系群体,利用该群体构建了包含184个SSR标记的遗传连锁图谱,图谱总长度为2 084.1 cM,平均图距为11.3 cM。在低光、高氮下和高光、低氮下对玉米苗期地上部干重、根干重、根冠比、最大根长进行了QTL定位分析,两种条件下共定位到21个与苗期根冠性状相关的QTL位点,低光、高氮条件下定位到11个QTL位点,高光、低氮条件下定位到10个QTL位点,分别位于第1、2、3、4、5、6、7、9染色体上。第6染色体上定位到7个位点,其中一个为控制低光、高氮下根干重的主效位点,贡献率为25.3%。在第1染色体上umc1335-bnlg1556区段同时检测到高光、低氮条件下地上部干重和根冠比的QTL位点,这些位点与地上部干物质的形成密切相关。

A genetic linkage map composing 184 simple sequence repeat（SSR） markers was constructed based on an Fs recombinant inbred line （RIL） population, derived from a cross between 478 × Wu312. The parents showed a significant difference in root and shoot traits. The total length of the map was 2 084.1 cM and the average distance between two markers of the map was 11.3 cM. RILs were cultured under high light-low nitrogen （HL-LN） and low light-high nitrogen（LL-HN）, respectively. Shoot dry weight（SDW）, root dry weight（RDW）, root / shoot（R/S）, and the maximum root length （MRL） were characterized for QTL identification. Under the two cultural conditions, 21 QTLs in total were detected for all the investigated traits. Eleven QTLs were found at LL-HN and 10 QTLs were found at HL-LN. These QTLs were located on chromosome 1, 2, 3, 4, 5, 6, 7, and 9, respectively. Seven QTLs were detected on chromosome 6, among which a major QTL counting for 25.3% of the variation of dry weight under LL-HN condition. A QTL between umc1335-bnlg1556 of chromosome 1 controlled both shoot dry weight and root to shoot ratio under the condition of HL-LN.