小麦品种冀麦24抗麦红吸浆虫QTL分析

QTL Analysis for Midge Resistance in Wheat Cultivar Jimai 24

麦红吸浆虫是影响小麦产量和品质的重要害虫,研究小麦对吸浆虫抗性的遗传及其连锁分子标记对于提高抗虫品种的选择效率具有重要意义。本研究以小麦感虫品系6218与抗虫品种冀麦24产生的重组近交系(RIL)群体为材料,利用SSR标记和人工虫圃对冀麦24的抗虫性遗传进行了研究。结果表明:6218与冀麦24的抗性差异显著,RIL群体在2年2点的鉴定中抗性稳定;所构建的遗传连锁图谱包含112个SSR位点,形成26个连锁群,图谱全长835.7 cM,标记间平均距离为7.5 cM。利用QTL IciMapping的完备区间作图法,在4A染色体上检测到1个加性效应位点(QSm.hbau-4A),该位点在2个鉴定年度的贡献率分别为9.67%、10.57%。该抗性QTL及其连锁SSR标记的发掘,将有助于提高小麦抗吸浆虫育种的选择效率。

Wheat blossom midge（ Sitodiplosis mosellana Gehin） is one of the most important insect pests in wheat,which has caused large losses for wheat production and its grain quality. However,for the invisible habitat of midge in soil and its accurate invasion into wheat just before wheat heading,it is difficult to lower or preclude the wheat losses incurred by midge using agronomic measures. Though the application of pesticide to kill midge is helpful in midge control,the effect is limited for the difficulties of midge monitoring and the risk of environment-balance destroy under field conditions. Using midge-resistant wheat lines or varieties has been documented an effective or environment-friendly way to control midge number in the field,thus reducing midge-caused wheat losses. But,breeding such wheat varieties needs introducing midges into wheat field to evaluate the resistance of different breeding lines,as will bring forth bad effects for assessing agronomic traits in wheat lines. The advent of molecular DNA markers and the introduction of marker-assisted selection（ MAS） approach into wheat breeding help to circumvent such embarrassment. Therefore,characterization of wheat resistance to midge based on quantitative trait loci（ QTLs）mapping and linked markers has important implications for improving the selection efficiency in breeding midgeresistant wheat varieties using genetic populations such as recombinant inbreeding lines（ RILs）. In present study,with recombinant inbred lines（ RILs） derived from the susceptible and resistant wheat lines,mapped the QTLs of midge resistance and characterized the relevant inheritance in wheat cultivar Jimai 24 using SSR markers and artificial midge nursery. The results showed that the resistance between lines 6218（ the susceptible wheat parent） and Jimai 24 were significantly different,and the resistance scales among RIL lines were genetically stable during thetwo consecutive years. A linkage map was constructed with 112 SSR loci,which comprised 26 linkage groups. The total length of the map was 835. 7 cM,and the average distance was 7. 5 cM between any two SSR markers. Using the Ici Mapping package for inclusive composite interval QTL mapping,a QTL,QSm. hbau-4 A,and its additive effects was identified on chromosome 4 A. The phenotypic variance explained（ PVE） of this locus in the two testing years were 9. 67% and 10. 57%,respectively. The mapping of this QTL and the identification of its linked SSR markers will facilitate the improvement of the selection efficiency for breeding midge-resistant wheat lines or varieties and fine-mapping of the midge-resistant QTL in the future.