小麦抗赤霉病研究现状与展望

小麦是我国最重要的口粮作物之一。在小麦生产所面临的各种病害中,赤霉病的发生具有愈来愈严重的趋势,引起小麦产业界的高度关注。近几十年来,科研人员在小麦抗赤霉病遗传育种以及防控技术领域进行了持续不懈的努力,在赤霉病病原菌致病基因、小麦赤霉病抗性基因定位、克隆及功能研究以及抗赤霉病分子育种等方面取得了重大进展。本文主要从赤霉病抗性基因资源的发掘和鉴定、不同抗源遗传基础解析、小麦赤霉病抗性基因、抗赤霉病分子标记辅助选择育种与基因聚合以及小麦抗赤霉病基因的克隆和功能研究等方面进行了综述,分析了目前小麦抗赤霉病研究中存在的问题,并提出应加强基因克隆、功能分子标记开发以及应用单体型辅助选择(HAS)和标记组辅助选择(MSAS)等小麦抗赤霉病研究的相关建议。     

基于干热风危害指数的黄淮海地区冬小麦干热风灾损评估

全球气候变化背景下,农业气象灾害呈上升态势。干热风灾害发生区域、次数和强度都发生了明显的变化。研究干热风灾害对农作物的影响对于我国农业可持续发展、保障粮食安全等均具有重要的现实意义。利用黄淮海地区68个气象台站1961—2010年的逐日气象资料,和54个农业气象试验站1981—2006年小麦的发育期、产量、干热风灾害等数据,采用公认的中国气象局2007年发布的气象行业标准《小麦干热风灾害等级》中冬小麦干热风灾害指标,计算干热风危害指数,进一步细化发育期,确定冬小麦抽穗前气象条件对气象产量影响的关键气象因子,分离干热风年冬小麦气象产量,构建重度干热风影响下干热风危害指数与冬小麦抽穗—成熟阶段气象条件对气象产量影响的统计模型,进行1981—2006年黄淮海地区冬小麦干热风灾损的评估。结果表明:(1)重度干热风危害下,1981—2006年期间黄淮海各地区冬小麦不同发育时段的干热风危害指数平均在抽穗—开花时段最大,乳熟—成熟时段居中,开花—乳熟时段最小,分别为0.17、0.15和0.14,平均0.15;(2)冬小麦抽穗前气象条件对气象产量影响的关键气象因子为:播种—出苗期间的最低气温、拔节—孕穗期间的平均气温和孕穗—抽穗期间的平均气温,各个单因子相关系数分别为0.64、0.86和0.99,均达到极显著水平。其中播种—出苗的最低气温可决定小麦出苗的迟早和苗情;拔节—孕穗期间,在小花原基形成期—四分体形成期气温偏低可延长小穗、小花分化时间,防止退化,提高结实率;孕穗—抽穗的平均气温偏高有利于提早抽穗,延长后期灌浆时间,且晴天有利于开花授粉;(3)分离干热风年冬小麦气象产量后,构建了重度干热风影响下干热风危害指数与冬小麦抽穗—成熟3个阶段气象条件对气象产量影响的统计模型,验证结果表明该模型客观上能够综合地反映干热风在不同发育阶段对小麦产量的影响。进一步灾损评估表明:重度干热风危害下,黄淮海地区冬小麦减产率在21.52%—39.80%之间,平均为27.83%。     

小麦梭条花叶病抗性遗传和育种研究进展

由土壤真菌禾谷多粘菌(Polymyxa graminis)传播的小麦梭条花叶病在我国长江流域和黄淮平原麦区已成为危害小麦生产的一种严重病害。本文系统地综述了我国在小麦梭条花叶病种质资源筛选、抗性机理、抗性遗传、抗病基因的分子标记以及抗病育种方面的进展。研究表明,在我国地方品种和改良品种中存在着较丰富的抗病资源;植物体内某些酶的活性和可溶性糖含量与抗性有密切的联系;抗病性表现为数量性状的遗传特征,可能受1~3对显性基因控制。通过抗感品种间杂交,可以育成抗病丰产的新品种。文中还对今后开展小麦抗梭条花叶病育种提出了几点建议。     

小麦抗白粉病基因

到目前为止,小麦中已经鉴定出31个主效抗白杨病基因位点(Pm1-Pm31),对这些小麦抗白粉病基因位点的来源、染色体定位、遗传特点以及载体品种等方面进行了概括性综述。     

植物细胞工程在小麦抗赤霉病育种中的应用

小麦赤霉病是全球性小麦病害,严重影响小麦产量和品质,赤霉菌产生的毒素进一步威胁人畜安全,培育抗病品种是控制小麦赤霉病危害的根本途径。植物细胞工程技术可创造新的遗传变异、加快育种进程,已经广泛应用于小麦抗赤霉病育种。概述了体细胞无性系变异诱导、花药培养、小麦与玉米杂交培育加倍单倍体以及幼胚培养一年多代快速成苗等植物细胞工程技术研究进展,着重介绍了其在抗小麦赤霉病育种中的应用。最后对未来发展趋势做了展望,植物细胞工程结合分子育种技术将在小麦抗赤霉病品种培育中发挥更重要的作用。     

小麦赤霉病抗病机制研究进展

小麦赤霉病是一种小麦穗部病害,严重影响小麦的产量和品质。挖掘小麦赤霉病抗性基因,揭示其抗病机制,对于提高小麦赤霉病抗性,推动小麦赤霉病抗性育种进程具有重要的意义。系统阐述了抗赤霉病相关QTL、多组学研究、细胞壁防卫、信号转导、次生代谢物合成、识别应答等小麦赤霉病抗性机制的研究进展,并对未来小麦赤霉病抗性机制的研究方向进行了探讨。希望以此加深研究者对小麦赤霉病抗性机制的了解,为未来小麦抗赤霉病分子机制研究提供理论基础,为小麦抗赤霉病遗传改良提供丰富的基因资源。     

我国小麦抗蚜机理研究进展

小麦蚜虫是我国重要的害虫类群,应用麦类作物品种抗虫性能有效减少化学杀虫剂的使用,减少天敌杀伤,保护农田生态环境。本文从经典的抗蚜三机制,物理抗性、化学抗性、诱导抗性,蚜虫地理种群(或生物型)与抗蚜性的关系,抗性遗传,抗蚜小麦品种和非寄主抗性的合理应用等方面综述了我国小麦抗蚜机理的研究成果,提出了研究的重点方向。     

小麦抗条锈病基因YrCN19的诊断检测和遗传分析

用小麦条锈病抗性基因YrCN19的诊断标记Xgwm410对19个小麦品种或品系进行PCR筛选,其中川农19、新抗5号、爱民5号和爱民6号扩增出与条锈病抗性基因YrCN19共分离的特征片断,其大小为391个碱基,而在其他的小麦品种或品系中未能检测到该片断。系谱分析和抗性鉴定结果表明川农19、新抗5号、爱民5号和爱民6号含有小麦条锈病基因YrCN19。抗性遗传分析发现小麦条锈病抗性在川农19,新抗5号和爱民5号中的遗传符合单个显性基因的遗传规律(3抗:1感);杂交组合烟辐188/爱民6号的抗性遗传也符合单个显性基因的遗传规律,而另外一些杂交组合(如R25/爱民6号,鲁955159/爱民6号和苏3110/爱民6号)中的抗性分离则符合两对基因互补的遗传规律(9抗:7感)。本研究揭示了小麦条锈病抗性基因YrCN19在不同遗传背景和杂交组合的抗性表达和分离有差异,从而加速YrCN19在小麦抗条锈育种中的开发与利用。     

DNA分子标记在小麦抗条锈性遗传研究中的应用

综述了近年来DNA分子标记在小麦抗条锈性遗传研究中的应用现状和潜力。内容涉及DNA分子标记在基因标记,基因克隆,遗传图谱构建和辅助选择育种等方面的应用,并列举了代表性实例,展望了DNA分子标记技术在小麦抗条锈病研究上的前景。     

小麦抗白粉病基因定位与分子标记

对小麦抗白粉病基因的遗传定位与分子标记进行了综述,介绍了小麦抗白粉病的遗传,并对今后的研究方向进行了讨论。     

水稻抗寒剂的效应及其施用技术

用KNO3（5g/L)和Na2HPO4(2g/L)及KH2PO3（2g/L)组合成抗寒剂（I）,混合比为1：1：1处理水稻种子和喷施幼苗能减轻早春寒害对幼苗的损伤;在寒露风来临之际,用KH2PO4（10g/L),Na2HPO4(2.5g/L)和尿素（10g/L)组成的抗寒剂（II)混合比为1：1：1喷施稻叶面能提高植株的抗冷性,促进颖花开裂,增加受精率和结实率,可以减轻寒露风对水稻产量的影响。     

半干旱区春小麦生长系统的人工神经网络模型与产量预测

以半干旱区春小麦生长系统为研究对象。探讨了作物生长系统中水分、土壤养分等生态因子的时空变化特征及春小麦产量形成机制,应用人工神经网络方法建立了半干旱区春小麦生长系统的产量随环境因子变化的神经网络模型,并与传统的CTM模型进行了比较。模拟结果表明,人工神经网络模型可适用于半干旱区春小麦生长系统产量随环境因子变化规律描述,且优于传统模型,从而为春小麦产量预测提供了新的途径,也为作物生态系统的人工调控提供了新的模式与定量依据。     

Breeding technology of alloplasmic wheat

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REML approach for adjusting the <Emphasis Type="Italic">Fusarium</Emphasis> head blight rating to a phenological date in inoculated selection experiments of wheat

Fusarium head blight is one of the most important wheat diseases causing grain yield and quality losses as well as mycotoxin contamination all over the world. Since Fusarium cannot be reliably controlled with fungicides, breeding has become a favorable tool to decrease the infection severity. In most cases, selection for Fusarium resistance is done by artificial infection in the field. However, there is a risk in preferring late heading genotypes, because heading of wheat is negatively correlated to head blight severity. Because an indirect selection for late maturity is not intended, we considered a statistical approach to avoid this problem. In this paper, we propose a mixed model to analyze extensive Fusarium head blight rating in resistance breeding experiments of wheat. The objective of the analysis was to select for Fusarium resistance, while at the same time ensuring that late heading genotypes, which show less head blight over the shorter vegetation period, are not preferred. Thus, selection was to be done such that genetic variability for heading date was retained. Therefore, the statistical model contained a covariate to adjust for differences in the heading date. The use of covariate adjustment is an easily handled alternative to a bivariate analysis. Covariate adjustment will in practice often work almost equally well as bivariate analysis. Any statistical software with powerful mixed model analysis tools can be used for this type of analysis. We propose an ad hoc method to obtain heritability estimates and a form of LSD (least significance difference) as a measure of accuracy on the basis of the proposed model and under special consideration of the experimental design. The ad hoc LSD was used as a rough measure to judge rankings of genotypic means (BLUPs). Friedman's super smoother was used to compare smoothed rank estimates for adjusted and unadjusted genotypes against increasing smoothed heading dates. Traits were transformed to meet the model assumptions, especially homogeneity of errors and normality, and back-transformation of means and standard errors was conducted by using the delta method.     

QTL analysis of resistance to Fusarium head blight in Swiss winter wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Fusarium head blight (FHB) of wheat is a widespread and destructive disease which occurs in humid and semi-humid areas. FHB epidemics can cause serious yield and quality losses under favorable climatic conditions, but the major concern is the contamination of grains with mycotoxins. Resistance to FHB is quantitatively inherited and greatly influenced by the environment. Its evaluation is costly and time-consuming. The genetic basis of FHB resistance has mainly been studied in spring wheat. The objective of this study was to map quantitative trait loci (QTLs) for resistance to FHB in a population of 240 recombinant inbred lines (RILs) derived from a cross between the two Swiss winter wheat cultivars Arina (resistant) and Forno (susceptible). The RILs were genotyped with microsatellite and RFLP markers. The resulting genetic map comprises 380 loci and spans 3,086 cM. The 240 RILs were evaluated for resistance to FHB in six field trials over 3 years. Composite interval mapping (CIM) analyses carried out on FHB AUDPC (i.e. mean values across six environments) revealed eight QTLs which altogether explained 47% of the phenotypic variance. The three main QTLs were mapped on the long arms of chromosomes 6D (R²=22%), 5B (R²=14%) and 4A (R²=10%). The QTL detected on 5B originated from the susceptible parent Forno. Other QTLs with smaller effects on FHB resistance were detected on chromosomes 2AL, 3AL, 3BL, 3DS and 5AL.Communicated by H.C. Becker     

Identification and molecular mapping of two QTLs with major effects for resistance to Fusarium head blight in wheat

Fusarium head blight (FHB) is a devastating disease of wheat worldwide. Novel sources of resistance are critical for improving FHB resistance levels in wheat. From a large-scale evaluation of germplasm for reactions to FHB, we identified one wheat accession (PI 277012) that consistently showed a high level of resistance in both greenhouse and field experiments. To characterize the FHB resistance in this accession, we developed a doubled haploid (DH) mapping population consisting of 130 lines from the cross between PI 277012 and the hard red spring wheat cultivar ‘Grandin’. The DH population was then evaluated for reactions to FHB in three greenhouse seasons and five field environments. Based on a linkage map that consisted of 340 SSR markers spanning 2,703 cM of genetic distance, two major quantitative trait loci (QTLs) for FHB resistance were identified on chromosome arms 5AS and 5AL, with each explaining up to 20 and 32% of the variation in FHB severity, respectively. The two QTLs also showed major effects on reducing the percentage of Fusarium damaged kernels (FDK) and deoxynivalenol (DON) accumulation in seeds. FHB resistance has not previously been reported to be associated with this particular genomic region of chromosome arm 5AL, thus indicating the novelty of FHB resistance in PI 277012. Plant maturity was not associated with FHB resistance and the effects of plant height on FHB resistance were minor. Therefore, these results suggest that PI 277012 is an excellent source for improving FHB resistance in wheat. The markers identified in this research are being used for marker-assisted introgression of the QTLs into adapted durum and hard red spring wheat cultivars.     

小麦转基因技术研究进展

小麦是我国的主要粮食作物,对其进行基因工程改良已成为研究的热点。近年来,利用转基因技术以提高小麦产量、改善品质、增强抗病虫和抗逆能力等相关研究日趋深入广泛。主要对目前小麦转基因研究现状进行综述,包括表达载体、报告基因与选择标记基因、目标基因、受体材料及转化方法等;并对当前小麦转基因技术存在的问题及育种潜力分析和展望。     

中国小麦主推品种和育成品系的抗倒伏性评价

倒伏是影响小麦产量的主要因素之一,选育抗倒伏性强的品种是育种研究的重点目标。本研究以528份我国主推的小麦品种和育成品系为材料,对影响小麦倒伏的主要性状进行测定,利用无偏线性估计值进行遗传变异分析、相关分析、主成分分析、线性回归分析和聚类分析,综合评价不同小麦品种的抗倒伏性。研究表明,6个抗倒伏性状在品种间都存在着广泛的遗传变异。基部节间长度、株高与抗推力呈极显著负相关,基部节间直径与抗推力呈极显著正相关,节间长度与节间直径相关性不显著。主成分分析表明,所有性状的信息可以用3个主成分代表,其累计贡献率达83.837%。回归分析结果表明,第1节间直径、第1节间长度、第2节间直径、第2节间长度和株高等5个性状均对抗推力有显著影响。依据抗推力将528份材料聚类为4类,其中第Ⅰ类群有66份小麦品种(系),其抗倒伏能力最强。研究结果为小麦抗倒伏品种利用、抗倒伏育种亲本的筛选以及育种后代品系的选育评价提供理论依据和技术支撑。     

小麦抗旱机理研究进展

干旱是影响小麦产量和品质的重要环境因素,而小麦在干旱胁迫下的抗旱机理非常复杂,不同程度以及不同发育时期的干旱胁迫对不同品种的影响各异。对近年来有关干旱胁迫下小麦的形态结构与渗透调节物质的变化,特别是基因和蛋白表达量的改变进行了综述,对小麦在干旱胁迫下如何提高品质及产量等问题提出建议。