Faculty of Sciences, Centre for Systems Biology, University of Southern Queensland, Toowoomba, QLD, 4350, Australia.
Theor Appl Genet. 2010 Jun;121(1):127-36. doi: 10.1007/s00122-010-1296-7. Epub 2010 Mar 3.
Crown rot of wheat (Triticum aestivum), predominantly caused by the fungus Fusarium pseudograminearum, has become an increasingly important disease constraint in many winter cereal production regions in Australia. Our group has previously identified a range of quantitative trait loci (QTL) for partial resistance to crown rot in various bread wheat sources. Here, we report on work that has assessed the effectiveness of pyramiding QTL to improve resistance to crown rot. Two doubled haploid populations were analysed--one from a cross between two previously characterised sources of partial seedling resistance (2-49 and W21MMT70; n = 208) and one from a cross between 2-49 and the commercial variety Sunco, a source of adult field resistance (n = 134). Both populations were phenotyped for seedling resistance to crown rot. Microsatellite and DArT markers were used to construct whole genome linkage maps for use in composite interval mapping (CIM) to identify QTL. Three QTL were detected in both trials conducted on the 2-49/W21MMT70 population. These were located on chromosomes 1D (QCr.usq-1D.1), 3B (QCr.usq-3B.1) and 7A. QCr.usq-1D.1 and the previously undetected 7A QTL were inherited from 2-49. QCr.usq-3B.1, inherited from W21MMT70, was the most significant of the QTL, explaining up to 40.5% of the phenotypic variance. Three QTL were identified in multiple trials of the Sunco/2-49 population. These were located on chromosomes 1D (QCr.usq-1D.1), 2B (QCr.usq-2B.2) and 4B (QCr.usq-4B.1). Only QCr.usq-2B.2 was inherited from Sunco. QCr.usq-4B.1 was the most significant of these QTL, explaining up to 19.1% of the phenotypic variance. In the 2-49/W21MMT70 population, several DH lines performed significantly better than either parent, with the best recording an average disease severity rating of only 3.8% of that scored by the susceptible check cultivar Puseas. These lines represent a new level of seedling crown rot resistance in wheat.
小麦冠腐病（Triticum aestivum）主要由镰刀菌（Fusarium pseudograminearum）引起，已成为澳大利亚许多冬小麦产区日益严重的病害制约因素。我们的研究团队先前已经确定了一系列针对不同面包小麦来源的部分冠腐病抗性的数量性状位点（QTL）。在这里，我们报告了评估聚合 QTL 以提高抗冠腐病能力的工作。分析了两个双单倍体群体 - 一个来自两个先前具有部分幼苗抗性特征的来源（2-49 和 W21MMT70；n = 208）的杂交，另一个来自 2-49 和商业品种 Sunco 的杂交，后者是田间成株抗性的来源（n = 134）。两个群体均对幼苗的抗冠腐病能力进行了表型分析。微卫星和 DArT 标记用于构建全基因组连锁图谱，用于复合区间作图（CIM）以鉴定 QTL。在对 2-49/W21MMT70 群体进行的两项试验中均检测到 3 个 QTL。这些 QTL 位于染色体 1D（QCr.usq-1D.1）、3B（QCr.usq-3B.1）和 7A。2-49 遗传了 QCr.usq-1D.1 和以前未检测到的 7A QTL。来自 W21MMT70 的 QCr.usq-3B.1 是 QTL 中最显著的，解释了高达 40.5%的表型方差。在 Sunco/2-49 群体的多项试验中鉴定到 3 个 QTL。这些 QTL 位于染色体 1D（QCr.usq-1D.1）、2B（QCr.usq-2B.2）和 4B（QCr.usq-4B.1）上。只有来自 Sunco 的 QCr.usq-2B.2 被遗传。这些 QTL 中，QCr.usq-4B.1 是最显著的，解释了高达 19.1%的表型方差。在 2-49/W21MMT70 群体中，一些 DH 系的表现明显优于双亲，最好的系记录的平均病情严重评分仅为易感对照品种 Puseas 评分的 3.8%。这些系代表了小麦幼苗冠腐病抗性的新水平。
