Establishment of Near Isogenic Lines of Huangzaosi Maize with Resistance against Maize Head Smut

[ Objective ] The paper was to establish the near isogenic lines of Huangzaosi maize with resistance against maize head smut, and to provide basis for its wide application in breeding and production. [Method] Combing with hybrid, backcress and self-cross method, as well as molecular markers, Huangzaosi maize was successfully introduced with head smut resistance, and its near isogenic lines were studied. The characteristics of resistant and susceptible variation and the changes of combining ability of near isogenic lines after backcrossing breeding were observed. [ Result ] The incidence rate of Huangzansi maize in control was 46% ; the incidence rates of the selected 24 near isogenic lines of resistant Huangzaosi were all lower than 10%, and the selected rate was 92.6% ; the combining ability of most near isogenic lines of resistant Huangzaosi maize had no significant difference with that of H^i maize in control; the yields of hybrids prepared by several inbred lines such as M135 and M140 were outstanding, which exceeded the control Zhengdan 958, showing a higher combining ability. [ Conclusion] The phenotype and combining ability of near isngenic lines of Huangzaosi maize with resistance against maize head smut obtained in the test were very close to Huan- gzaosi, and its resistance against maize head smut was greatly increased, thus solving the problems of Huangzaesi without resistance against maize head smut.

Control of Maize Head Smut with 6% Tebuconazole FS

In order to test the control effect of 6% tebuconazole FS on maize head smut and to select its optimal dose for mixing seed, field tests were performed in 2012 and 2013. The results showed that 6% tebuconazole FS was effective to control maize head smut, and the control effect ranged from 73.4% to 91.1%. In addition, it also improved the maize yield by 36.7%-44.1%, compared with the blank control. The optimal dose of 6% tebuconazole FS for seed dressing was 166.5 g/100 kg to control head smut on maize.

Damage Characteristics and Control Measures of Maize Head Smut

Maize head smut is a worldwide disease, widely occurred in most maize fields. The disease had occurred in large area in the late 1970s, and became a limiting factor restricting the improvement of maize yield and total yield in China. After efforts of several generations of agricultural scientific workers, the symp- toms, pathogen, infection pathway, infection conditions, infection regularity and resistance genetic law of maize head smut have been studied. This paper introduces the incidence symptoms, pathogen sources, infection pathway, infection conditions, and physiological races of maize head smut, and put forwards the corresponding prevention measures, such as crop rotation, selection of resistant varieties, seed dressing, soil treatment with fungicides, promoting seedling emergence and strengthening field management.

Response of Sorghum Accessions against Newly Documented Pathotypes 5 and 6 of Head Smut Pathogen, <i>Sporisorium reilianum</i>

This study was conducted to identify resistance sources against the newly documented pathotypes (P5 and P6) of Sporisorium reilianum, causing sorghum head smut. A subset of 67 sorghum association panel (SAP) accessions, 29 in 2017 and 38 in 2018 along with checks BTx635 (resistant) and BTx643 (susceptible) were screened in the greenhouse against P5 and P6 pathotypes in two separate experiments in both years. At 18 to 20 days after planting, accessions were inoculated by injecting the seedlings below the apical meristem with sporidial suspensions following an established inoculation procedure. Three accessions (PI656091, PI533919, and PI533821) in 2017 and 17 accessions (PI597961, PI656071, PI656048, PI576435, PI534075, PI534145, PI656057, PI576437, PI651492, PI656014, PI656025, PI655999, PI656010, PI656082, PI534123, PI533927, PI656100) in 2018 were identified as potential resistant sources to both P5 and P6 pathotypes of S. reilianum. These SAP accessions are new sources that can be further used to develop new breeding parental lines and hybrids and mapping populations for quantitative trait loci markers closely linked to head smut resistance.

Inhibition of the spread of endophytic Sporisorium reilianum renders maize resistance to head smut

Head smut, caused by the fungal pathogen Sporisorium reilianum, poses a grave threat to maize(Zea mays) production worldwide. Here we report cytological and molecular evidence for maize resistance to head smut. During early stages of root infection, S. reilianum mycelium was capable of penetrating the root epidermis of both resistant(Ji1037) and susceptible(HZ4) inbred lines. S. reilianum hyphae were observed in the root–stem junction at 6 days after inoculation. In an attempt to monitor hyphal spread within the maize plant,a highly specific and sensitive real-time PCR method was established to estimate the hyphal content in infected maize tissues. During the upward growth of endophytic S.reilianum, the extent of hyphal spread was markedly different between Ji1037 and HZ4. Very little or no pathogen was detected in aerial parts of Ji1037, whereas large amounts of pathogen accumulated in aboveground tissues, particularly inflorescences, of HZ4. Thus,maize resistance to S. reilianum was achieved mainly by inhibition of endophytic hyphal growth rather than by prevention of early-root penetration by the pathogen.

A maize WAK-SnRK1a2-WRKY module regulates nutrient availability to defend against head smut disease

Obligate biotrophs depend on living hosts for nutrient acquisition to complete their life cycle,yet the mechanisms by which hosts restrict nutrient availability to pathogens remain largely unknown.The fungal pathogen Sporisorium reilianum infects maize seedlings and causes head smut disease in inflorescences at maturity,while a cell wall-associated kinase,ZmWAK,provides quantitative resistance against it.In this study,we demonstrate that S.reilianum can rapidly activate ZmWAK kinase activity,which is sustained by the 407th threonine residue in the juxtamembrane domain,enabling it to interact with and phosphorylate ZmSnRK1a2,a conserved sucrose non-fermenting-related kinase a subunit.The activated ZmSnRK1a2 translocates from the cytoplasm to the nucleus,where it phosphorylates and destabilizes the transcription factor ZmWRKY53.The reduced ZmWRKY53 abundance leads to the downregulation of genes involved in transmembrane transport and carbohydrate metabolism,resulting in nutrient starvation for S.reilianum in the apoplast.Collectively,our study uncovers a WAK-SnRK1a2-WRKY53 signaling module in maize that conveys phosphorylation cascades from the plasma membrane to the nucleus to confer plant resistance against head smut in maize,offering new insights and potential targets for crop disease management.

东北春玉米区玉米丝黑穗病大发生原因及对策

2002年东北春玉米区玉米丝黑穗病大发生。本文作者受农业部农业技术推广服务中心良繁处委托,对东北春玉米区玉米丝黑穗病大发生情况进行了普查。结果表明,东北三省发病面积近106.7万hm2,占玉米总面积的19.5%。一般品种发病率在7%左右;感病品种发病率在10%～40%;个别高感品种的发病率在50%以上。主要原因是玉米多年重茬连作,缺乏抗病品种,气候条件变化异常以及农民缺乏科学使用种衣剂的常识。提出以抗病品种为基础,化学防治为主农业保健栽培措施为辅的综合防治对策。

玉米抗丝黑穗病种质鉴定及遗传研究

丝黑穗病是我国玉米生产的重要病害之一。试验采用人工接种鉴定法研究黑龙江省常用玉米自交系和部分国内骨干系对丝黑穗病的抗性。在54份自交系中,鉴定出4份高抗系和8份抗病系,感病和高感系占64.9%。PB血缘材料中既有高抗材料,也有感或高感材料;含Mo17和自330血缘的材料多数抗或高抗玉米丝黑穗病,尤其是含Mo17血缘材料抗性更强;而含黄早四血缘的材料多高感玉米丝黑穗病;Ried血缘材料多属于中抗或感病类型。玉米对丝黑穗病的抗性遗传属核遗传,F1的发病率介于抗、感亲本之间,接近于双亲的平均值,不存在正反交差异。欲培育中抗以上类型杂交种,其双亲发病率应较低,杂交方式应为高抗×高抗;高抗×抗病;高抗×中抗;高抗×感病;抗病×抗病;抗病×中抗。

基于PCR技术的玉米丝轴黑粉菌侵染率及扩展进程的研究

【目的】以对玉米丝黑穗病高感的黄早四和抗病的Mo17自交系为材料,用丝轴黑粉菌进行接种,研究病菌对玉米的侵染率及扩展进程。【方法】采用丝黑穗病病原菌基因组特异引物的PCR技术,分别对幼苗期的根、叶和成熟期的根、茎、叶、雄穗生长锥DNA进行PCR扩增。【结果】特异引物的PCR技术不仅能够在早期准确鉴定玉米幼苗是否受到病菌的侵染,而且可以跟踪丝轴黑粉菌在体内扩展进程。【结论】玉米对丝黑穗病的抗性差异主要表现为抗侵染和抗扩展,抽穗期雄穗对病樱的形成不能表现出明显的抗性效应。

玉米丝黑穗病的研究进展

玉米丝黑穗病是玉米生产的重要病害。本文首次系统地综述了丝黑穗病的危害、病原、防治措施、抗源鉴定和抗性遗传研究进展 ,探讨了该领域存在的主要问题。我国应加强对玉米丝黑穗病的抗源鉴定与抗性遗传研究 。

玉米种质对丝黑穗病的抗性分析及发病条件研究

为明确不同玉米种质资源对丝黑穗病的抗性差异,本研究于2012—2015年间采用人工接种法对1 164份玉米种质进行了田间抗性鉴定,结果表明,38份材料03GEM00041、07GEM02289、07GEM02902等表现高抗,占比3.26%;61份材料W6、478、4619、A580等表现抗病,占鉴定种质的5.24%;W22、W216、W286等140份表现中抗,占比12.03%;其余566份和359份分别表现感病和高感,分别占总鉴定材料的48.63%和30.84%。经过对比发现,不同地区玉米种质抗性强弱以及抗性多样性存在较大的差异,来自云南和广东的种质其抗性水平明显低于内蒙古和黑龙江。通过聚类分析发现,41份材料可划分为5类。在系谱图上,抗病性相同的品种大致划分在同一个类中,但也存在一定的偏差。研究结果同时表明0～10cm的土壤温度在15.8～17.9℃,病株率在85%以上,为适宜发病温度,其中15.8℃为最佳发病温度;接菌量为0.3%时的病株率明显高于接菌量为0.1%和0.2%的病株率。

安全高效防治玉米丝黑穗病种衣剂的研制

通过田间和室内人工模拟低温条件,重复再现了烯唑醇产生药害的症状,首次明确了烯唑醇药剂产生药害的原因,找出了解决的办法。研制出安全、高效防治玉米丝黑穗病的种衣剂“Hc”,克服了烯唑醇遇低温易产生药害问题,试验示范防治效果达88.6%。

玉米种质资源对丝黑穗病的抗性鉴定

采用新的抗性评价标准,对162份普通玉米自交系、22份爆裂玉米自交系、59份甜玉米自交系及122份糯玉米自交系人工接种丝黑穗病菌并进行抗性鉴定,筛选出US3195等127份抗病系,占鉴定总数的34.80%,多数材料尤其是特用玉米材料感或高感丝黑穗病,无免疫及高抗材料。

玉米苗期病害诊断与防治技术研究

采用常规的方法对玉米苗期病害发生进行了诊断及防治技术研究。结果表明:玉米苗期病害可初步分为侵染性和非侵染性病害。侵染性病害主要是由病原菌侵入引起,符合KOCH法则的病原菌主要有禾谷镰孢菌(Fusariumgraminearum)、串珠镰孢菌(Fusariummoniliforme)、玉米圆斑离蠕孢菌(Helminthosporiumcarbo num)、立枯丝核菌(Rhizoctoniasolani)、串珠镰孢菌胶孢变种(F moniliformevar subglutinans)和丝轴团散黑粉菌[Sporisoriumreilianum(KuHn)LandonetFull]及玉米假单胞杆菌(PseudomonaszeaeHsiaetFang)。非侵染性病害主要包括缺素症、环境胁迫和药害等因素引起的病害。使用克百威、福美双、三唑醇和戊唑醇复配的二元或三元种衣剂,可以有效地控制玉米苗期病虫害和丝黑穗病的发生与危害。

玉米抗丝黑穗病遗传特性研究

1999～ 2 0 0 0年 ,对选育自交系及杂交组合 ,采用人工接种鉴定方法进行抗性试验。结果表明 :玉米自交系对丝黑穗病的抗性受遗传因子和土壤带菌特性共同作用 ;抗性的遗传特点属核遗传 ,不受胞质基因控制 ;

糜子叶片防御酶系及抗氧化物质对黑穗病菌胁迫的响应

【目的】黑穗病是威胁糜子产量的重要病害,防治黑穗病最有效的方法是种植抗病品种。本研究测定黑穗病菌胁迫对糜子叶片防御酶系活性及抗氧化物质含量的影响,筛选鉴定糜子黑穗病抗性的生理生化指标,为选育抗黑穗病的糜子品种提供理论支撑。【方法】以不同糜子资源为材料,田间种植条件下采用种子饱和接种法接种黑穗病菌,2012—2013年进行糜子黑穗病抗性鉴定,筛选不同抗性的糜子品种。2014年研究不同抗性糜子苗期(SS)、拔节期(ES)、抽穗期(HS)、灌浆期(FS)叶片防御酶系及抗氧化物质对黑穗病菌胁迫的响应,防御酶系测定苯丙氨酸解氨酶(PAL)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性,抗氧化物质测定抗坏血酸(As A)、还原型谷胱甘肽(GSH)含量。【结果】经连续两年糜子黑穗病抗性鉴定,黑虼蚤(R1)、驴驼川(R2)和小麦糜子(R3)平均发病率分别为0、0和0.73%,为抗病品种;黄硬黍(S1)、宁04-262(S2)和Ym0965(S3)平均发病率分别为19.71%、19.86%和32.28%,为感病品种。接种糜子黑穗病菌后,感病品种糜子叶片PAL活性变化幅度大于抗病品种,表现在拔节期PAL活性为3 610.8 U·g^(-1) FW,显著高于抗病品种的2 520.7 U·g^(-1) FW,而灌浆期为2 425.0 U·g^(-1) FW,显著低于抗病品种的2946.0 U·g^(-1) FW。抗、感品种糜子叶片APX活性均呈先降低后升高的变化趋势,拔节期显著最低;感病品种糜子叶片APX活性在抽穗期和灌浆期(分别为461.1 U·g^(-1) FW和516.7U·g^(-1)FW)显著高于抗病品种(分别为361.5 U·g^(-1)FW和428.2 U·g^(-1)FW)。2类品种叶片GR活性变化呈先升高后降低趋势,抽穗期GR活性显著高于其他3个时期;且抽穗期感病品种叶片GR活性显著高于抗病品种,其中感病和抗病品种糜子叶片平均GR活性分别为271.9和167.4 U·g^(-1)FW。糜子受黑穗病菌胁迫后,6个品种叶片As A含量在147.7—344.8μg·g^(-1)FW范围内波动,无明显规律,且抗、感品种间无显著差异。抗病品种糜子叶片GSH含量从苗期到抽穗期显著降低后到灌浆期又显著升高,而感病品种糜子叶片GSH含量从苗期到抽穗期显著降低后到灌浆期并无显著变化,并且灌浆期抗病品种叶片GSH含量为984.7μg·g^(-1)FW,显著高于感病品种的676.0μg·g^(-1)FW。【结论】不同糜子品种对黑穗病的抗性不同,黑穗病菌胁迫可引起糜子叶片防御酶活性及抗氧化物质含量变化,拔节期和灌浆期PAL活性、抽穗期和灌浆期APX活性、抽穗期GR活性、灌浆期GSH含量在抗病品种和感病品种间存在显著差异,可作为鉴定糜子对黑穗病抗性的生理生化指标。

玉米抗丝黑穗病QTL分析

以Mo17（抗）×黄早四（感）的F2分离群体（191个单株）为作图群体，构建了含有84个SSR位点和48个AFLP位点的遗传连锁图谱，全长1542．9cM，平均图距11．7cM。在吉林省公主岭和黑龙江省哈尔滨2个地点，通过人工接种方法对184个相应的F3家系（缺失7个）进行抗病鉴定。采用复合区间作图法对抗丝黑穗病数量性状位点（QTL）进行定位及遗传效应分析。在吉林公主岭地区检测到5个QTL，分别位于第1、2、3、8、9染色体上，解释的表型方差为10．0％。16．3％。在黑龙江哈尔滨地区也检测到5个QTL，分别位于第1、2、3、4、7染色体上，解释的表型方差为4．6％。13．4％。比较分析发现，两地一致在第2、3染色体上各检测到1个QTL，其中第2染色体上的表现为超显性效应，第3染色体上的表现为加性效应。研究结果为玉米抗丝黑穗病种质改良提供了重要信息。

玉米丝黑穗病侵染率与发病率关系的PCR检测分析

用2个感病的玉米材料接种玉米丝黑穗病菌,苗期调查侵染率,开花期调查发病率,结果表明侵染率显著高于发病率;在开花期提取未发病植株茎髓组织DNA进行PCR检测,结果检测到玉米丝黑穗病菌DNA的存在。因此,通常情况下玉米丝黑穗病侵染率大于发病率。

玉米抗丝黑穗病的基因效应

利用2个抗玉米丝黑穗病自交系(齐319和Mo17)与2个感病系(E28和黄早四),组配4个抗感杂交组合。2004年,对4个组合的亲本、F1、F2、BCR(F1与抗病亲本回交1代)和BCS(F1与感病亲本回交1代)6个世代群体分别在北京和黑龙江进行丝黑穗病的人工接种鉴定,采用世代平均值分析玉米抗丝黑穗病的遗传特点。研究表明,各杂交组合的抗病性均含有显著的加性效应,其中3个组合有显著的显性效应。不同杂交组合的抗病遗传模式表现不同,用感病亲本E28组配的2个组合(齐319×E28)和(Mo17×E28)的抗病性基本符合加性-显性遗传模型;而用另一个感病亲本黄早四组配的组合(齐319×黄早四)和(Mo17×黄早四)的抗病性存在明显的上位性效应。这说明玉米对丝黑穗病的抗性呈现较复杂的遗传模式。因此,在抗玉米丝黑穗病育种中既要重视对自交系抗病水平的鉴定,也要加强杂种F1的合理组配及抗病性评估。

玉米丝黑穗病带菌现象的发现与验证

通过多年观察研究玉米丝黑穗病发病条件,发现存在带菌植株现象。采用干旱处理,研究侵染率与发病率差异、特异引物PCR检测等多方面验证,明确提出玉米丝黑穗病大发生的原因,并探讨其在相关研究中的应用。