苯醚甲环唑和丙环唑对玉米锈病防治效果不理想

<正>为有效控制黄淮海夏玉米区玉米后期叶斑病,河北省农科院植保所、山东省济宁市农科院研究人员通过人工接种和自然发病两种方式,针对玉米小斑病、南方锈病和弯孢叶斑病进行了叶斑病防治技术的研究。结果表明,选用10%苯醚甲环唑WG     

河西走廊制种玉米3种真菌性叶斑病的诊断与识别

玉米大斑病、玉米小斑病和弯孢菌叶斑病是河西走廊制种玉米生育中后期发生的主要叶部病害。为了提高对这3种叶斑病的田间诊断和识别水平,对其发病情况进行了田间调查,归纳总结出3种病害的症状特点,并对引起病害的病原菌进行了分离与鉴定。结果表明,3种叶斑病在发病时期、病斑形态、病斑大小、病状等方面区别明显;在供试的10种玉米自交系品种中,大斑病、小斑病和弯孢菌叶斑病的发病率和病情指数存在明显的差异;分离到引起玉米叶斑病的真菌病原13种,其中玉米弯孢菌叶斑病Curvulairia lunata(Walke)Boedijn、玉米大斑病Exserohilum turcicum(Pass)Leonard et Suggs和玉米小斑病Bipolaris maydis(Nishik.et Miyake)Shoemaker分离率较高。     

多雨季节玉米要防治大斑病

<正>前段时间雨水较多,玉米大斑病大流行。玉米大斑病,又称长蠕孢菌叶斑病、煤霉病、煤纹病、枯叶病、条斑病、叶斑病等,是玉米的重要叶部病害,在冷凉地产区发病较重,一般减产10%左右,严重地块达到30%~50%。当玉米植株70~90厘米高时即可发病,主要为害玉米叶片,严重时波及叶鞘、苞叶和籽粒。田间发病始于下部叶片,逐渐向上发展,也有从中上部叶片开始的。苗期很少发病,抽雄后发病加重。     

玉米叶斑病的流行原因及防治方法

莘县常年种植玉米5．3万hm^2,近几年常发叶斑病害有大斑病、小斑病、顶腐病、弯孢霉叶斑病等。它们单独发生或混合发生,主要危害玉米叶片,也有的危害叶鞘、苞叶和茎秆,一般从植株中下部叶片开始发病,逐渐向上扩展。天气适宜时,大量的病菌聚集,致叶片失去光合作用,失去功能,严重影响玉米后期的产量,造成较大的损失。     

黄淮海区玉米叶斑病和南方锈病的发生与防治

近年来,弯孢菌叶斑病、南方锈病的发生与流行已成为直接影响黄淮海夏玉米产量的主要因素之一。本文综述了黄淮海夏玉米弯孢菌叶斑病和南方锈病的为害、症状、病原、发生规律、发病诱因和相应的综合防治措施。     

双鸭山市玉米主要病虫害及防治措施

1玉米大斑病 1．1表现症状及传播途径 1．1．1表现症状玉米大斑病又称条斑病、枯叶病、叶斑病,主要为害玉米叶片,严重时为害叶鞘和苞叶。田间发病始于下部叶片,逐渐向上发展,形成中央黄褐色,     

我国玉米南方锈病发生区域和玉米品种田间抗性的研究

通过对河南、山东、安徽等近20个省市的广泛调查以及有关田间发病记载数据的整理,明确了玉米南方锈病的准确发生地区.黄淮海夏玉米区以及海南省是当前我国玉米南方锈病发生的重点区域,病害对生产影响明显,其次为广西、广东等南方玉米区,西南玉米区局部有轻微发生,该区域主要发生的是普通锈病.汇总接种鉴定以及数年田间鉴定和国家玉米区域试验点记载的数据,获得了黄淮海夏玉米区47份推广品种对南方锈病的抗性水平情况,其中登海3号和天泰10号为高抗南方锈病品种,鲁单981、农大108、中科4号等14份也具有较好的田间抗性,但目前在该区域种植面积最大的郑单958和浚单20则属于高感品种.积极推广抗南方锈病品种是有效控制病害,减少生产损失的惟一选择.     

玉米种质资源大规模多年多点多病害的自然发病抗性鉴定

病害是影响玉米生产的重要因素。利用品种的抗性是控制玉米病害的经济、安全和有效措施。2016—2019年间,在黄淮海和东华北地区,首次对2000份来源广泛且遗传背景丰富的玉米种质资源进行了多年多点多病害的田间自然发生条件下抗病性鉴定,部分材料在西北地区也进行了田间鉴定,重点调查了小斑病、茎腐病、瘤黑粉病、弯孢叶斑病、南方锈病、粗缩病、大斑病、灰斑病和丝黑穗病的抗病性。综合4年共10个不同环境的自然发病下抗性鉴定数据表明,自然发病鉴定的结果受环境因素影响较大,表现为年度间和地域间的差异。在所有鉴定的病害中,小斑病在多个年份和多个鉴定点的发病均比较充分, 11份种质对该病害表现出稳定抗性;茎腐病、大斑病和灰斑病,在不同年份的部分鉴定点发病较为充分,对这3种病害表现抗病的种质分别为440、356和423份,综合抗性鉴定结果具有较大的参考价值;弯孢叶斑病、瘤黑粉病和粗缩病仅在1个鉴定点发病较为充分,南方锈病和丝黑穗病在所有鉴定点均发生较轻,鉴定结果有待进一步验证。本研究筛选出一批在不同环境条件下对多种病害均具有稳定抗性的材料,其中JN15、953、沈977、68122、K21、SC24-1、17MC7211、17MC7223、郑591、161191等种质的综合抗性突出,对种质的利用及后续人工接种精准鉴定的种质选择具重要参考价值。     

兼抗叶斑病和锈病的云南福贡红小豆

尾孢菌叶斑病及锈病是危害小豆的两种重要病害,常造成叶片枯萎早期落叶,导致严重减产和失收。“七五”期间,对1000份小豆种质材料分别进行叶斑病,锈病田间人工接种鉴定,经过初鉴和复鉴,筛选出云南福贡红小豆,对上述两种病害均表现抗病和高抗。对叶斑病鉴定病级为1级,病情指数     

玉米大、小斑病的综合防治技术

<正>1症状及病原菌1.1症状玉米大、小斑病是影响玉米产量和质量的主要病害,大斑病的发生较小斑病晚。玉米大、小斑病主要发生在叶片上,有时侵染叶鞘和苞叶,在玉米抽穗后发病较重。小斑病在叶片上的病斑小而多,色较浅,发病初期叶面上产生褐色半透明水渍状斑点,逐渐扩展为近椭圆形黄褐色病斑。边缘紫褐色,较明显,有时为2~3     

木霉可湿性粉剂对玉米小斑病的生物防治作用

玉米小斑病是我国南方玉米产区主要叶部病害之一,为探索防治玉米小斑病的生物农药,采用实验室培养皿理想试验与玉米苗盆栽试验,观察木霉菌可湿性粉剂对病原菌菌丝生长、玉米叶片变化及玉米防御反应相关酶活的测定。实验室结果表明,木霉菌可湿性粉剂强烈抑制玉米小斑病菌菌丝生长;盆栽结果表明,喷洒木霉可湿性粉剂抑制了小斑病菌对玉米叶片的侵染。同时喷施12h、24小时后木霉菌可湿性粉剂诱导玉米防御相关的POD和PAL酶活升高。     

玉米大斑病生防菌的筛选、鉴定及应用研究

为了从生物途径探索有效控制大斑病在玉米生产带来的危害,本试验以玉米大斑病菌(Setosphaeria turcica)为目标菌株,采用对峙法和盆栽接种试验获取生防菌,并测定其盆栽防治效果。结果表明：从128株玉米内生细菌获得1株对玉米大斑病菌拮抗效果最佳的菌株,最长半径与最短半径比值为2.9。从玉米内部分离到的内生生防细菌YD7对大斑病菌具有较强拮抗效果。根据YD7菌株形态培养特征、生理生化特征及16S rDNA序列分析结果鉴定为解淀粉芽孢杆菌。经过2次盆栽测定,YD7对玉米大斑病防治效果分别为78.2%和77.8%。综合表明,YD7防治玉米大斑病具有很好的开发前景。     

玉米大斑病广谱抗性外引自交系的发掘与抗病基因初步鉴定

从2014—2016年连续3年对43份来自美国、法国、俄罗斯和德国的玉米资源进行了抗大斑病人工接种鉴定, 筛选到高抗玉米大斑病材料7份, 抗病材料1份, 中抗材料6份, 抗性材料占鉴定总材料的比例为32.6%。利用F₂群体, 对7份高抗材料进行了大斑病抗性遗传分析, 抗感植株分离比例和适合性测验证明, 自交系A04、F02、F05和R01对大斑病的抗性可能是由一对显性基因控制的。抗谱分析表明, 自交系A04、F02、F05和R01携带的抗大斑病基因不同于Ht1、Ht2、Ht3和HtN, 可能是新的抗病基因。该研究结果可为今后我国玉米大斑病抗性种质的引进及改良提供重要参考。     

Field assay of seedling and adult-plant resistance to southern leaf blight in maize

Resistance to southern corn leaf blight is under the control of a single recessive allele, rhm, and can be scored from lesion number, size, type and sporulation in the lesion, which are best expressed by plants growing under field conditions, although resistance also can be measured at the seedling stage. An assay procedure that can unequivocally score disease severity from the seedling stage to post‐flowering in the field is desirable. We analysed pairs of isogenic lines H95/H95rhm and B73/B73Htrhm, the F₂ population of H95 × H95rhm consisting of a total of 687 individuals, and 120 F₃ families, which were inoculated with conidia of Bipolaris maydis race O. The disease ratings were also studied together with the segregation scores of a single copy DNA probe, agrP144. Among 687 F₂ plants derived from the cross H95 x H95rhm, 161 plants were rated as resistant and 526 susceptible, suggesting a 1: 3 ratio. Among the 120 F₃ families, there were 32 susceptible, 58 segregating and 30 resistant rows, fitting the expected 1:2:1 ratio for a single gene model. Using agrP144 as a marker, 99.5% restriction fragment length polymorphism (RFLP) allelic segregation scores corresponded to the disease ratings obtained from field data, indicating that the marker agrP144 is tightly linked to the rhm locus. Similarly, the amplified fragment length polymorphism (AFLP) marker p7m36 also is closely linked to the locus but on the opposite side of the marker agrP144.     

Inheritance of foliar resistance to Phytophthora palmivora (butler) Butler in cacao (theobroma cacao L.)

The genetic nature of resistance in leaves of cacao (Theobroma cacao L.) to Phytophthora palmivora (Butler) Butler was investigated in a 3 × 8 and a 4 × 4 mating design. Leaf resistance was assessed at the penetration and post-penetration stages of infection. Wide variability was observed among the 32 families examined for lesion frequency (penetration resistance) and lesion size / spread (post-penetration resistance). Segregation within families showed a continuous distribution for both forms of resistance, suggesting that resistance is polygenic. The poor association between resistance at the penetration stage and that at the post-penetration stage suggested that they were independently inherited and could be selected independently with the aim of accumulating genes for resistance. Genetic complementation between the two forms of resistance and transgressive segregation were evident within the families studied. The additive effects were predominant for lesion size, while both additive and non-additive effects were important in the inheritance of lesion frequency. The narrow sense heritabilities obtained from North Carolina Model II analysis were as high as 0.61 and 0.40 for lesion size and lesion frequency respectively. Possible breeding strategies based on these findings are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genes for resistance to northern corn leaf blight in diverse maize populations

Turcicum or northern corn leaf blight (NCLB) incited by the ascomycete Setosphaeria turcica, anamorph Exserohilum turcicum, is a ubiquitous foliar disease of maize. Diverse sources of qualitative and quantitative resistance are available but qualitative resistances (Ht genes) are often unstable. In the tropics especially, they are either overcome by new virulent races or they suffer from climatically sensitive expression. Quantitative resistance is expressed independently of the physical environment and has never succumbed to S. turcica pathotypes in the field. This review emphasizes the identification and mapping of genes related to quantitative NCLB resistance. We deal with the consistency of the genomic positions of quantitative trait loci (QTL) controlling resistance across different maize populations, and with the clustering of genes for resistance to S. turcica and other fungal pathogens or insect pests in the maize genome. Implications from these findings for further genomic research and resistance breeding are drawn. Incubation period (IP) and area under the disease progress curve (AUDPC), based on multiple disease ratings, are important component traits of quantitative NCLB resistance. They are generally tightly correlated (r_p? 0.8) and highly heritable (h²? 0.75). QTL for resistance to NCLB (IP and AUDPC) were identified and characterized in three mapping populations (A, B, C). Population A, a set of 121‐150 F₃ families of the cross B52×mo17, represented US Corn Belt germplasm with a moderate level of resistance. It was field‐tested in Iowa, USA, and Kenya, and genotyped at 112 restriction fragment length polymorphism (RFLP) loci. Population B consisted of 194‐256 F₃ families of the cross Lo951×CML202, the first parent being a Corn‐Belt‐derived European inbred line and the second parent being a highly resistant tropical African inbred line. The population was also tested in Kenya and genotyped with 110 RFLP markers. Population C was derived from a cross between two early‐maturing European inbred lines, D32 and D145, both having a moderate level of resistance. A total of 220 F₃ families were tested in Switzerland and characterized with 87 RFLP and seven SSR markers. In each of the three studies, 12‐13 QTL were detected by composite interval mapping at a signifcance threshold of LOD=2.5. The phenotypic and the genotypic variance were explained to an extent of 50‐70% and 60‐80%, respectively. Gene action was additive to partly dominant, as in previous generation means and combining ability analyses with other genetic material. In each population, gene effects of the QTL were of similar magnitude and no putative major genes were discovered. QTL for AUDPC were located on chromosomes 1 to 9. All three populations carried QTL in identical genomic regions on chromosomes 3 (bin 3.06/07), 5 (bin 3.06/07) and 8 (bin 8.05/06). The major genes Ht2 and Htn1 were also mapped to bins 8.05 and 8.06, suggesting the presence of a cluster of closely linked major and minor genes. The chromosomal bins 3.05, 5.04 and 8.05, or adjacent intervals, were further associated with QTL and major genes for resistance to eight other fungal diseases and insect pests of maize. Bins 1.05/07 and 9.05 were found to carry population‐specifc genes for resistance to S. turcica and other organisms. Several disease lesion mimic mutations, resistance gene analogues and genes encoding pathogenesis‐related proteins were mapped to regions harbouring NCLB resistance QTL.     

不同玉米自交系南方锈病的抗性评价

通过对14个骨干玉米自交系4～5叶期接种南方锈病病原菌,分析了在温室和大田种植条件下,不同自交系在不同发育时期的抗感表现和危害程度。结果表明,自交系齐319表现抗病,其余自交系则表现不同程度的感病;随着玉米的发育进程,南方锈病在感病玉米植株迅速蔓延,开花授粉期叶片被锈菌夏孢子堆覆盖,植株褪绿,不能正常进行     

番木瓜植株镁钾含量变化与缺钾叶枯病的关系

采用田间调查、采样及其室内分析与田间试验相结合的方法,在低钾而高镁的土壤上,从植株各个部位探索番木瓜植株镁、钾营养变化对其生理性缺钾叶枯症的影响。结果表明,番木瓜叶枯症的发生,除与土壤有效钾缺乏有关外,Mg/K比值过高也是导致该症发生的一个重要原因。发生缺钾叶枯病的番木瓜植株,其根、茎、叶片、叶柄等器官含镁量均明显提高,施用钾肥后不但提高了植株的含K量,而且能抑制番木瓜植株对镁的吸收,从而协调平衡Mg/K比值,生理性缺钾叶枯症得到有效控制。     

玉米品种对不同地区玉米南方锈菌的抗性评价

为明确我国各地区玉米品种对玉米南方锈病的抗性水平,为品种推广和抗病品种科学布局提供依据,利用85个玉米品种对海南三亚、广东河源、广西河池和湖南邵东4个地区的玉米南方锈菌菌株进行了田间抗病性比较试验。结果表明,相同品种对不同地区来源菌株的抗性水平有差异。综合各地区玉米南方锈菌的抗性评价可知,玉研505、鲁宁184、蠡玉88、太平洋99和绿海200等9个品种对玉米南方锈病的抗性最强,优迪598、三北63、联创839和冠玉911等19个品种次之,禾新9号、德禹M8、宁玉502、新玉27和晨强808等17个品种抗病性最弱。供试品种中,表现为高抗、中抗和感病的品种百分比分别为10.59%、22.35%和67.06%,说明我国玉米品种整体上表现为对玉米南方锈病抗性较差,病害容易流行,需注意预防。     

西南地区水稻品种对水稻白叶枯病的抗性分析

为了明确西南地区不同水稻品种对白叶枯病的抗谱,促进抗病品种在生产上的直接利用。采用云南省、贵州省和四川省当前生产上主栽和即将推出的水稻品种（系）共267个,对2008年和2009年中国目前流行的水稻白叶枯病菌9个生理小种进行了品种的抗性评价。结果表明,C5、C7、C8、C9为西南地区的优势小种,其中只有云南存在抗C8小种的水稻品种,占总参试品种的10.11%。对不同白叶枯菌进行致病力分析表明,C8小种致病力最强,平均病斑长度达(23.7±8.3) cm。研究结果还表明,大面积种植的优质稻红优系列、‘滇屯502’对西南地区白叶枯病菌优势小种表现为高抗。