基于四交群体的玉米叶夹角和叶向值QTL定位分析

选育耐密紧凑株型是增加玉米单位面积产量的重要途径之一,而叶夹角和叶向值是衡量株型的重要参数。本研究选用叶夹角和叶向值存在差异的玉米自交系郑58、PH6WC、87-1和自330构建1个四交(郑58/豫87-1//PH6WC/自330)组合,以228个四交F1单株为作图群体,构建了1张含225个SSR位点,全长1 387.2cM的玉米分子标记遗传连锁图谱,标记间平均间距为6.19cM。基于四交群体应用区间作图法检测4个环境下的QTL,共检测到13个叶夹角相关QTL,分别位于第1、2、3、4、5、7和10染色体上,单个QTL可解释5.1%~20.0%的表型变异;检测到15个叶向值相关QTL,分别位于第1、2、4、5、7、8和9染色体上,单个QTL可解释5.4%~20.1%的表型变异。其中qLA-E2-2和qLA-E4-2落在同一标记区间umc1692-umc2297(bin 5.03),分别解释16.6%和13.2%的表型变异;qLO-E1-1、qLO-E3-2和qLA-E4-1落在同一标记区间umc1568-bnlg1953(bin1.02),分别解释10.1%、19.9%和12.3%的表型变异;qLO-E2-1和qLO-E3-1落在同一标记区间phi056-phi427913(bin 1.01),分别解释13.8%和10.0%的表型变异。这些多个环境共同检测到的QTL将为玉米耐密理想株型育种中叶夹角叶向值的分子标记辅助选择提供有益信息,加速耐密株型玉米品种的选育。

QTL mapping for leaf angle and leaf orientation in maizeusing a four-way cross population

Selecting more compact plants for higher density planting is an important way to increase yield per unit area of maize (Zea mays L.),and leaf angle and leaf orientation are very important traits affecting maize plant type.In this study,a four-way cross population was constructed with four inbred lines (Zheng58,PH6WC,Yu87-1,Zi330) which were significantly different in leaf angle and leaf orientation.A genetic linkage map containing 225 simple sequence repeat (SSR) markers was constructed based on a mapping population consisting of the 228 F₁ individuals from the four-way cross,and spanned a total of 1 387.2 cM with an average interval of 6.19 cM.Quantitative trait loci (QTLs) for leaf angle and leaf orientation were identified in whole genome with interval mapping in four environments.13 QTLs of 28 total QTLs were identified for leaf angle on chromosomes 1,2,3,4,5,7 and 10,and the phenotypic variance explained by each QTL ranged from 5.1% to 20.0%.The other 15 QTLs were identified association with leaf orientation on chromosomes 1,2,4,5,7,8 and 9 accounting for 5.4% to 20.1% of the phenotypic variance.qLA-E2-2 and qLA-E4-2 were found in the same marker interval umc1692-umc2297 (bin 5.03),and phenotypic variations explained were 16.6% and 13.2%,respectively.qLO-E1-1,qLO-E3-2 and qLA-E4-1 were found in the same marker interval umc1568-bnlg1953 (bin 1.02),and phenotypic variation explained were 10.1%,19.9% and 12.3%,respectively;qLO-E2-1 and qLO-E3-1 were found in the same marker interval phi056-phi427913 (bin 1.01),and phenotypic variation explained were 13.8% and 10.0%,respectively.These QTLs detected under multiple environments provide useful information for marker-assisted selection of leaf angle and leaf orientation in maize compact breeding,and thus have the potential to accelerate the breeding of compact variety in maize.