小麦旗叶长、宽及面积的QTL分析

Mapping QTLs for Flag Leaf Length,Width and Area in Wheat

以小麦品种‘小偃81’和‘西农1376’构建的含236个家系的自交重组系（RIL）群体（F2：7、F2：8代）为研究材料,采用完全随机区组设计,连续2年在陕西杨陵、河南驻马店和山东济南于灌浆期（花后20 d）随机取每个株系10株测量旗叶长、宽,并利用172个SSR标记构建了遗传连锁图谱,通过基于完备区间作图法的QTL IciMapping V3.2软件,对控制小麦旗叶长、宽和面积的数量性状位点（QTL）进行了加性效应分析。结果发现：（1）9个旗叶长QTLs位于1A、4A、3B、5D和7D染色体上,单个QTL可解释5.10%~16.44%的表型变异;10个旗叶宽QTLs位于1A、3A、5A、7A、3B和5D染色体上,单个QTL可解释4.63%~14.24%的表型变异;12个旗叶面积QTLs位于1A、4A、3B、2D和5D染色体上,单个QTL可解释4.25%~22.67%的表型变异。（2）控制小麦旗叶长、宽和面积的QTLs存在差异,同一QTL在不同性状中的遗传贡献率也不同。（3）同一性状在同一年份,不同地点和在不同年份,相同地点下检测到的QTLs有的相同,但有的差异明显。（4）有些控制不同性状的QTLs在染色体的同一标记区间,表现一因多效。研究表明：位于1A和5D染色体上的2个加性QTLs都同时控制旗叶长、宽和面积,且前者为主效基因,后者遗传贡献率也较大,可用于标记辅助育种和分子聚合育种。

In the present study,a population of 236 RIL（F7 and F8 generation） derived from two elite Chinese wheat （Triticum aestivum L.） cultivars ‘Xiaoyan 81’ and ‘Xinong 1376’,were used in an experimental study in Yangling of Shaanxi Province,Zhumadian of Henan Province and Jinan of Shandong Province for two consecutive years.The genetic linkage map was constructed with 172 SSR markers and the additive QTLs for the flag leaf length,width and area in wheat were analyzed through the software QTL IciMapping V3.2 which is based on the inclusive composite interval mapping.The results showed that：（1）9 QTLs for flag leaf length were located on chromosomes 1A,4A,3B,5D and 7D,single QTL explaining 5.10%~16.44% of the phenotypic variances.10 QTLs were located on chromosomes 1A,3A,5A,7A,3B and 5D,detected for flag leaf width,single QTL explaining the phenotypic variations from 4.63%~14.24%.12 QTLs for flag leaf area were mapped on 1A,4A,3B,2D and 5D chromosomes,accounting for 4.25%~22.67% of the phenotypic variations.（2）QTLs for flag leaf length,width and area were different and the genetic contribution of the same QTL were also variant in different phenotypic traits.（3）Among the QTLs for the same trait in the same year in different locations and those in the different years in the same location,some were the same but the others were different.（4）Some QTLs for different traits were located at the same marker interval of a chromosome and they performed pleiotropy.The results suggested that 2 QTLs detected on chromosomes 1A and 5D controlled the flag leaf length,width and area in wheat together.Besides,the former was the main effect gene and the phenotypic variation of latter was significant so that they could be used in marker-assisted selection breeding and polymerization breeding.