【作者】 王岩；

【导师】 田纪春；

【作者基本信息】 山东农业大学 ， 作物遗传育种， 2009， 硕士

【摘要】 小麦等农作物的许多重要农艺性状(如产量性状、生育期、抗逆性等)和品质性状是由多基因控制的数量性状(QTL)。作物性状QTL定位使用的遗传群体主要包括分F2等分离群体和RILs等永久性群体。“IF2”群体由永久群体中的每个纯合株系按一定组配方案两两杂交获得,既具有F2群体信息量大、可以估计显性效应以及与显性有关的上位性效应的优点,又具有RILs或DH等永久群体可以组配出足量的种子满足多年多点试验需要,以取得准确的表型观测值,有利于鉴别紧密连锁的QTL标记的优点。本研究以花培3号×豫麦57的双单倍体(Doubled Haploid,DH)群体为基础构建了永久F2群体,构建了小麦分子遗传图谱,并利用基于混合线性模型的QTLNetwork 2.0软件,对小麦分蘖、株高进行了QTL定位,旨在为研究小麦分蘖、株高QTL及其遗传效应提供参考,对小麦分蘖株高的分子标记辅助选择育种有很大的应用价值和理论意义取得的主要结果如下:1小麦“永久F2”群体的构建花培3号和豫麦57杂交F1通过花药培养,经染色体加倍获得168个双单倍体(doubled-haploid,DH)群体。2007年5月根据“永久F2”组配方案,将168个DH系随机分成两组,每组包含84个DH系,从两组DH系中各随机选择1个DH系组配成一个杂交组合,然后再从剩余的DH系中各选出1个DH系进行组配,依次类推。通过一轮杂交组配84个杂交组合,经两轮杂交,获得包含168个杂交组合的一套“IF2”群体。2利用“永久F2”群体定位小麦株高的QTL利用一套覆盖小麦21条染色体、含有324个SSR标记的遗传连锁图谱对小麦株高进行QTL定位研究,使用基于混合线性模型的QTLNetwork 2.0软件进行QTL分析。在“永久F2”群体中定位了7个株高QTL,包括4个加性QTL,一个显性QTL,一对上位性QTL,共解释株高变异的20%,其中位于4D染色体的qPh4D,具有最大的遗传效应,贡献率为7.5%;位于2D染色体显性效应位点qPh2D,可解释1.6%的表型变异;位于5B-6D染色体上位效应位点,可解释1.7%的表型变异。还发现加性效应、显性效应和上位效应对小麦株高的遗传起重要作用,并且基因与环境具有互作效应,结果表明利用“永久F2”群体进行QTL定位研究的方法有助于分子标记辅助育种3利用“永久F2”群体定位小麦分蘖的QTL在“永久F2”群体中定位了3个分蘖QTL,包括2个加性QTL,一个显性QTL,共解释分蘖变异的13.1%,小麦分蘖的2个加性QTL位于5A,5D染色体,其中位于5D染色体的qTn5D,具有最大的遗传效应,贡献率为9.9%,在各环境中稳定表达,并且具有环境互作效应;位于5A染色体的qTn3A可解释0.43%的表型变异。位于5A染色体显性效应位点qTn5A具有环境互作效应,在泰安可解释2.88%的表型变异,在聊城可解释2.68%的表型变异更多还原

【Abstract】 Common wheat is one of the most important staple crops world-wide. The grain yield and other important agronomic traits and quality traits of wheat are generally controlled by multiple genes, and inherited as QTL. With the development of molecular genetics and genomics, location,seperation and expoiting QTL have become an important and essential component element in crop genetic improvement. The work will not only prepare gene resources for molecular marker assisted selection and molecular breeding by design, but also lay a foundation for fine mapping and clone some important genes. In the present study, we report a new genetic linkage map developed from an immortalized F2, which was generated from the cross between two elite Chinese common wheat varieties Huapei 3 and Yumai 57. QTL analyses were performed using the software of QTLNetwork 2.0 based on the mixed linear model approach. QTLs for plant height and tiller. The results were as the following1. A set of doubled haploid (DH) lines were used to construct an immortalized F2 (IF2) population comprising 168 different crosses. Based on the method of the IF2 population, the 168 RILs were first randomly divided into two groups, each group containing 84 RILs. The 84 RILs from one group were each paired with an RIL from the other group without replacement, producing 84 different crosses in one round of interbreeding. This procedure was repeated two times, producing a set of the IF2 populations containing 168 different crosses.2. Linkage map was constructed with 324 SSR markers covering the whole wheat genome, including 284 SSR, 37 ESTs loci, 1 ISSR loci and 2 HMW-GS loci, was constructed. This linkage map covered a total length of 2,485.7 cM with an average distance of 7.67 cM between adjacent markers. QTL analyses were performed using the software QTLNetwork version 2.0 based on the mixed linear model at P < 0.05 level. Four additive QTLs, 1 dominance QTL and pair of epistatic QTLs were detected, the total QTL effects detected for the plant height explained 20% of the phenotypic variation. One QTL qPh4D for plant height was identified on chromosome 4D, was identified on chromosome 2D, explaining 7.5% of the phenotypic variances. Dominance effect loci qPh2D was identified on chromosome 2D, explaining 1.6% of the phenotypic variances;Epistatic effects of loci was identified on chromosome 5B—6D,explaining 1.7% of the phenotypic variances . The results indicate additive effects, dominance effects and epistatic effects are important in genetics of wheat for plant height, which are also subjected to environmental modifications. These results further demonstrate that the use of " IF2" groups QTL positioning research methods contribute to the molecular marker-assisted breeding3. Linkage map was constructed with 324 SSR markers covering the whole wheat genome, including 284 SSR, 37 ESTs loci, 1 ISSR loci and 2 HMW-GS loci, was constructed. This linkage map covered a total length of 2,485.7 cM with an average distance of 7.67 cM between adjacent markers. QTL analyses were performed using the software QTLNetwork version 2.0 based on the mixed linear model at P < 0.05 level. Two additive QTLs, 1 dominance QTL were detected, the total QTL effects detected for the tiller explained 13.1% of the phenotypic variation. One QTL qTn5D for tiller was identified on chromosome5D, explaining 9.9% of the phenotypic variances. Dominance effect loci qTn5A was identified on chromosome 5A, explaining 2.88% of the phenotypic variances in Taian and explaining 2.68% of the phenotypic variances in liaocheng. The results indicate additive effects, dominance effects and epistatic effects are important in genetics of wheat for tiller, which are also subjected to environmental modifications. These results further demonstrate that the use of " IF2" groups QTL positioning research methods contribute to the molecular marker-assisted breeding更多还原