Wheat Yield in a Tolerant Winter Wheat Line Infested by Hessian Fly (<i>Mayetiola destructor</i>)

The Hessian fly, Mayetiola destructor, is a harmful pest of wheat (Triticum aestivum). Pioneer variety 25R78 is putatively tolerant, meaning that the plant can survive successful Hessian fly infestation with reduced growth effects. To understand if Hessian fly-tolerance in wheat results in reduced yield effects and to analyze the economic feasibility of tolerant wheat as a Hessian fly control method, this study focused on analyzing the effect of infestation on tolerant wheat yield. This study analyzed tolerant Pioneer variety 25R78, resistant Pioneer brand variety 25R32, and susceptible Pioneer brand variety 25R47 through harvest. Treated plants were infested using a plastic cover and allowing 1 - 2 female flies to lay eggs for two hours. We measured head, fertile head number and tiller number. Seeds were analyzed by measuring total seed number and weight, as well as average seed number and weight. Tolerant and resistant plants showed no significant effects on yield in comparison to susceptible wheat. The infested tolerant plants were comparable in yield to infested resistant plants. Therefore, we propose that tolerance incorporated into wheat varieties will lower selection pressure on Hessian fly populations and increase the durability of these wheat lines.

Relationship of Secreted Salivary Protein Variants to Virulence in Hessian Fly (<i>Mayetiola destructor</i>(Say))

Salivary proteins are the initial contact between sedentary insect pests and their host plants. It is expected that one or more salivary proteins mediate the interaction between Hessian fly and wheat, in which a feeding site is established to the benefit of the fly. A survey of 52 loci annotated as insect secreted salivary proteins was conducted in 384 individuals evenly distributed among eight biotypes of Hessian fly (B, C, D, E, GP, L, O, and vH9). Amplicons were sequenced with Illumina, and sequence reads were aligned to the reference sequences from which primers had been designed. Positions of consistent base variation (998 in all) were identified and tabulated by biotype. No varying position was associated with biotype-wide virulence to any one of wheat resistance genes H3, H5, H6, H7/H8, H9, H11, H13, and H26. The multiplate pooling strategy utilized in this study is an effective, affordable way to reveal the genotype of hundreds of individuals at tens of genetic loci.

Genes encoding a group of related small secreted proteins from the gut of Hessian fly larvae [Mayetiola destructor （Say）]

A group of related genes has been isolated and characterized from the gut of Hessian fly larvae [Mayetiola destructor （Say）]. Members in this group appear to encode proteins with secretary signal peptides at the N-terminals. The mature putative proteins are small, acidic proteins with calculated molecular masses of 14.5 to 15.3 kDa, and isoelectric points from 4.56 to 4.88. Northern blot analysis revealed that these genes are expressed predominantly in the gut of Hessian fly larvae and pupae. Two related genes, GIOK1 and GIOK2, were isolated as tandem repeats. Both genes contain three exons and two introns. The intron/exon boundaries were conserved in terms of amino acid encoding, suggesting that they arose by gene duplication. The fact that the frequency of this group of clones in a gut cDNA library higher than that of total cDNA clones encoding digestive enzymes suggested that this group of proteins may perform an important function in the gut physiology of this insect. However, the exact functions of these proteins are as yet known since no sequence similarity could be identified between these proteins and any known sequences in public databases using standard methods.

检疫害虫黑森瘿蚊的形态特征与为害状识别

黑森瘿蚊[Mayetiola destructor(Say)]是重要的国际性检疫害虫,我国仅分布于新疆,近年在局部地区严重发生。黑森瘿蚊在小麦苗期的为害状与麦秆蝇(Meromyza saltatrix L.)相似,易引起混淆。本文描述了黑森瘿蚊各虫态的鉴别特征及其在小麦上的为害症状,提出了与麦秆蝇的鉴别方法。

Identification of a major QTL for Hessian fly resistance in wheat cultivar‘Chokwang’

The Hessian fly(HF,Mayetiola destructor)is one of the destructive pests of wheat(Triticum aestivum L.)worldwide.Resistant cultivars can effectively minimize wheat damage due to this insect pest.To identify new quantitative trait loci(QTL)for HF resistance,a population of recombinant inbred lines(RILs)was developed from a cross between the HF-resistant wheat cultivar‘Chokwang’and susceptible wheat‘Ning 7840’,and phenotyped for responses to HF attack.A linkage map was constructed using 1147 single nucleotide polymorphism(SNP)markers generated from genotyping-by-sequencing(GBS).One major QTL,QHf.hwwg-6 BS,for HF-resistance was identified on chromosome arm 6 BS,which explained up to84.0%of the phenotypic variation and was contributed by Chokwang.Two RILs showed recombination in the candidate interval of QHf.hwwg-6 BS,which delimited QHf.hwwg-6 BS to a 4.75 Mb physical interval between 6,028,601 bp and 10,779,424 bp on chromosome arm 6 BS of IWGSC Chinese Spring reference genome Ref Seq v2.0.Seven GBS-SNPs in the candidate interval were converted into Kompetitive allele specific polymerase chain reaction(KASP)markers.Two of them,KASP-6 B112698 and KASP-6 B7901215,were validated in a U.S.winter wheat panel.KASP-6 B112698 was nearly diagnostic,thus can be used to screen QHf.hwwg-6 BS and pyramid it with other resistance genes in breeding programs.

基于CLIMEX的黑森瘿蚊在我国的潜在适生区预测

本研究利用"CLIMEX+GIS"的方法,对黑森瘿蚊(Mayetiola destructor)在中国的适生性情况进行了分析预测。结果表明黑森瘿蚊在我国大部分地区较为适生,适生区面积占全国的66.45%。根据预测情况,提出了相应的植物检疫措施建议。可为检验检疫部门提供决策支持,对于防控该虫的传入也具有重要实践意义。

黑森瘿蚊在新疆博州的发生现状及原因分析

黑森瘿蚊局部分布于我国新疆,近年在博尔塔拉州局部暴发。为有效控制疫情,通过疫情普查和定点观察,调查了黑森瘿蚊的分布范围和发生特点,分析了疫情发生原因。黑森瘿蚊目前主要分布于温泉县和博乐市,以春季世代危害为主,在温泉县春小麦、博乐市冬小麦上发生严重。引起疫情发生的主要原因是敏感小麦品种大面积种植、适宜的气候条件和防治措施不到位。并对此提出了相应的控制对策。

黑森瘿蚊触角结构观察

采用光学显微镜和扫描电镜观察了黑森瘿蚊(Mayetiola destructor (Say))成虫的触角结构。观察结果表明,触角由16～18节组成,包括柄节、梗节和14～16节鞭小节。雄虫触角主要为17节,雌虫为16节。鞭小节的愈合、鞭节末节出现缢缩是造成触角节数发生变异的原因。