小麦“N553×扬麦13”RIL群体小穗密度、株高及赤霉病抗性QTL分析

为了发掘新的抗赤霉病基因,以抗赤霉病新种质N553与扬麦13构建的包含184个家系的重组自交系(RILs)为材料,利用217对在双亲间具有多态性的分子标记构建遗传连锁图谱,利用该图谱对小穗密度、株高及赤霉病抗性进行QTL检测,并分析了小穗密度及株高与赤霉病抗性的相关性。结果表明,本研究共检测到5个赤霉病抗性相关QTL,其中1个效应较大的QTL位于2D染色体上,位于标记wmc18-cfd233之间,可解释8.17%~11.42%的表型变异;在3B染色体短臂上检测到1个QTL,位于标记barc102-gwm533之间,可解释5.33%~42.96%的表型变异。QFhb.jaas-2DS与QFhb.jaas-3BS聚合可显著增强小麦赤霉病抗性。另外3个QTL贡献率小于10%,分别位于染色体2B、3B、4A上。检测到与小穗密度相关的QTL有1个,位于3B染色体上,可解释5.36%~6.08%的表型变异。检测到与株高相关的QTL有5个,分别位于染色体4A、7A、5B、6B上,可解释5.2%~8.93%的表型变异。小穗密度与赤霉病抗性呈正相关,株高与抗扩展抗性无相关性,与抗侵染抗性呈负相关。结合以上QTL检测及相关性分析结果可知,QFhb.jaas-3BL可能不是赤霉病抗性位点。因此,包括QFhb.jaas-3BL在内的贡献率小于10%且仅在单一环境下检测到的3个赤霉病抗性相关QTL需进一步进行多年多点试验。

QTL Analysis for Agronomic Traits and Fusarium Head Blight (FHB) Resistance Using Recombinant Inbred Lines of Wheat

In order to discover new quantitative trait loci (QTL) for Fusarium head blight (FHB) resistance,a total of 2 018 simple sequence repeats (SSRs) and sequence tagged site (STS) markers were analyzed between parents N553 and Yangmai 13 for genetic map construction and QTL scanning. In this research, 217 polymorphic markers were identified and used to screen a population of 184 recombinant inbred lines (RILs) derived from a cross between N553 and Yangmai 13. Results showed that, five QTLs were found for FHB resistance using WinQTLcart 2.5 software. Among them, two QTLs were contributed by N553 and the other three were contributed by Yangmai 13. A stable major QTL, QFhb.jaas-2DS,was detected on the short arm of chromosome 2D, which could explain 8.17% to 11.42% of phenotypic variation for FHB resistance. A second stable major QTL, QFhb.jaas-3BS, was identified to be located between marker barc102 and gwm493, which could explain 5.33% to 42.96% of phenotypic variation for FHB resistance. Besides, three other minor QTLs on chromosome 2BS, 3BL and 4AS with less than 10% explanation of phenotypic variations in individual experiments were detected. The polymerization of these two major QTLs ( QFhb.jaas-2DS and QFhb.jaas-3BS) was proved to significantly increase the resistance to FHB. At the same time, one QTL related to spikelet compactness (SC) was mapped on chromosome 3B, explaining 5.36% to 6.08% of phenotypic variation; five QTLs associated with plant height (PH) were mapped on chromosomes 4A, 7A, 5B, 6B, explaining 5.2% to 8.93% of phenotypic variation.Correlation analysis showed that spikelet compactness had a significantly positive correlation with FHB resistance, while plant height had a significantly negative correlation with resistance to infection of FHB, and no significant correlation with resistance to spread of FHB.Combined with the result of QTL detection and correlation analysis,we know that QFhb.jaas-3BL may not be the locus of FHB resistance.Therefore,three QTLs related to FHB resistance and detected in a single environment,with a contribution rate less than 10%,need to be fureber tested in multi-site experiments for many years.