【作者】 刘斌；

【导师】 谢彦周； 杨辉；

【作者基本信息】 西北农林科技大学 ， 农业硕士（专业学位）， 2025， 硕士

【摘要】 小麦作为我国主要粮食作物之一,其安全生产对保障国家粮食安全意义重大。然而,小麦赤霉病的发生不仅导致小麦产量大幅降低,还对小麦品质造成严重破坏。尤其是在黄淮冬麦区,赤霉病已成为限制小麦生产的最主要病害之一。培育抗病品种是防控赤霉病最经济、环保、有效的措施。尽管当前黄淮冬麦区主栽小麦品种在赤霉病抗性和农艺性状改良方面已取得一定成效,但仍难以满足绿色高产的现代农业生产需求。本研究拟运用矮败小麦结合分子标记辅助选择的方法,旨在选育出赤霉病抗性强、农艺性状优良的小麦新种质,为黄淮冬麦区小麦抗赤霉病育种提供重要的种质资源。主要研究结果如下:1.群体构建与新品系选育:基于实验室前期创制的矮败小麦基础群体开展两轮回交试验,第一轮,以田间表型鉴定筛选出的矮秆不育单株为受体亲本,以徐麦DH9、徐麦17252等11个品系(种)为供体亲本,筛选出矮败小麦轮选群体。第二轮,在小麦苗期利用分子标记检测提前确定目标植株,并以此为受体亲本,徐麦DH9、徐麦17252等11个品系(种)为供体亲本,筛选出矮败小麦抗赤霉病改良群体。每轮回交均定向选择优良可育株进入选种圃。经PCR跟踪检测、田间接种鉴定及农艺性状筛选,最终选育出45份中抗赤霉病且农艺性状优良的品系——轮选抗赤24。2.赤霉病抗性鉴定:矮败小麦基础群体平均病小穗率为49.31%,平均严重度为3.50,处于高感水平,矮败小麦抗赤霉病改良群体平均病小穗率为40.41%,平均严重度为3.05,处于中感水平,而轮选抗赤24群体平均病小穗率为30.25%,平均严重度为2.24,达到中抗水平。3.基因型鉴定与分析:利用太谷核不育基因Ms2的特异性标记HT5,实现了矮败小麦矮秆不育株苗期基因型的精准鉴定。同时,通过抗赤霉病基因的分子标记检测发现,矮败小麦抗赤霉病改良群体在抗病基因的聚合程度上显著优于矮败小麦基础群体,Fhb1、Fhb2、Fhb5、QFhs.crc-2DL、Fhb1+Fhb5、Fhb5+QFhs.crc-2DL基因的携带比例分别为30.77%、6.84%、53.00%、38.46%、19.66%和23.93%。在轮选抗赤24群体中,QFhs.crc-2DL、Fhb2、Fhb4基因的携带比例显著提高,而Fhb1基因未被检测到。4.相关性分析:对可育单株后代自交产生家系的平均严重度与农艺性状的相关性分析表明,平均严重度与株高呈显著负相关,平均严重度与小穗密度呈显著正相关。说明随着株高增加、穗码变稀,品系的赤霉病抗性也会增强。5.综合农艺性状分析:筛选出的45份中抗赤霉病小麦新种质在株高、穗长、小穗数和千粒重等主要农艺性状上表现优异,且抗赤霉病基因Fhb2、Fhb4、Fhb5、QFhs.crc-2DL与株高偏高、小穗密度低、籽粒质量差等不良性状无明显的关联性,为后续小麦育种提供了优良材料。更多还原

【Abstract】 As one of the major staple food crops in China,the safe production of wheat is of great significance for ensuring national food security.However,the occurrence of Fusarium head blight(FHB)not only leads to a substantial reduction in wheat yield but also causes severe damage to the quality of wheat.Especially in the Yellow and Huai River Valley Winter Wheat Zone,FHB has become one of the most important diseases restricting wheat production.Cultivating disease-resistant varieties is the most economical,environmentally friendly,and effective measure for preventing and controlling FHB.Although certain achievements have been made in improving the FHB resistance and agronomic traits of the main cultivated wheat varieties in YHWZ,they still cannot meet the needs of modern agricultural production for green and high yield.This study intends to use the method of combining dwarf sterile wheat with molecular marker-assisted selection,aiming to breed new wheat germplasms with strong FHB resistance and excellent agronomic traits,and provide important germplasm resources for wheat breeding for FHB resistance in YHWZ.The main research results are as follows:1.Population Construction and New Line Breeding:Two rounds of backcrossing experiments were conducted based on the basic population of dwarf sterile wheat created earlier in the laboratory.In the first round,using the dwarf sterile single plants screened through field phenotypic identification as recipient parents,and using 11 lines(varieties)such as Xumai DH9 and Xumai17252 as the donor parents,a dwarf sterile wheat rotational selection population was screened.In the second round,molecular marker detection was used at the seedling stage of wheat to determine the target plants in advance.Using these plants as recipient parents and 11 lines(cultivars)such as Xumai DH9 and Xumai17252 as donor parents,an improvedh population of dwarf sterile wheat resistant to FHB was screened out.In each round of backcrossing,excellent fertile plants were directionally selected to enter the seedling nursery.Through PCR tracking detection,field inoculation identification,and agronomic trait screening,finally,45 lines moderately resistant to FHB and with excellent agronomic traits——Recurrent Selection Resistant to FHB 24 were bred.2.Resistance Evaluation of FHB:The basic population of dwarf sterile wheat had an average disease spikelet rate of 49.31%and an average severity of 3.50,which is at the highly susceptible(S)level.The improved population of dwarf sterile wheat resistant to FHB had an average disease spikelet rate of 40.41%and an average severity of 3.05,which is at the moderately susceptible(MS)level.While the Recurrent Selection Resistant to FHB 24 population had an average disease spikelet rate of 30.25%and an average severity of 2.24,reaching the moderately resistant(MR)level.3.Genotype Identification and Analysis:By using the specific marker HT5 of the Taigu genic male-sterile gene Ms2,the precise identification of the genotypes of dwarf sterile plants of dwarf sterile wheat at the seedling stage was achieved.Meanwhile,through the molecular marker detection of FHB resistance genes,it was found that the FHB resistance improved population of dwarf sterile wheat was significantly superior to the basic population of dwarf sterile wheat in terms of the aggregation degree of disease resistance genes.The carrying ratios of Fhb1,Fhb2,Fhb5,QFhs.crc-2DL,Fhb1+Fhb5,and Fhb5+QFhs.crc-2DL genes were 30.77%,6.84%,53.00%,38.46%,19.66%,and23.93%respectively.In the Recurrent Selection Resistant to FHB 24 population,the carrying ratios of QFhs.crc-2DL,Fhb2,and Fhb4 genes were significantly increased,while the Fhb1 gene was not detected.4.Correlation Analysis:The correlation analysis between the average severity of the families self-crossed from the offspring of fertile single plants and the agronomic traits showed that the average severity was significantly negatively correlated with the plant height,and significantly positively correlated with the spikelet density.This indicates that as the plant height increases and the spikelets become sparser,the resistance of the lines to FHB will also increase.5.Comprehensive Analysis of Agronomic Traits:The 45 newly screened wheat germplasms moderately resistant to FHB performed excellently in the main agronomic traits such as plant height,spike length,number of spikelets,and thousand-grain weight.Moreover,there was no obvious correlation between the FHB resistance genes Fhb2,Fhb4,Fhb5,QFhs.crc-2DL and the adverse traits such as higher plant height,low spikelet density,and poor grain quality,providing excellent materials for subsequent wheat breeding.更多还原