栽培大麦×纤毛鹅观草属间杂种后代系抗赤霉病研究

 本文研究了栽培大麦×纤毛鹅观草属间杂种后代60个系群及其亲本在接菌条件下的抗赤霉病表现。从每穗发病百分率、发病动态进程和穗轴病变率等多个侧面对属间杂种后代系的抗性进行了分析。结果表明:1.发病百分率:参试各系未出现高抗(小穗受害率< 3.93%)和高感(小穗受害率> 57.3%)的类型。后代系属R级(抗病)的共7系,占11.7%;属MR级(中抗)的共25系,占41.7%;其余28系属MS级(中感)和S级(感染),占46.7%。当按病情指数来划分时,则R级和MR级所占比例更大。2.变动系数:属抗病级的各系,在接菌后第8 d的第一次调查中,基本上未发病,以后各期的变动系数均小;属感病级的各系,第一次调查时感病就重,以后各期的变动系数也高。3.属抗病的各系,穗轴节的病变最轻,感病各系较重,大麦亲本最重。此外,还讨论了作物对赤霉病抗性的机理、抗性级别划分标准和属间基因转移等问题。     

小麦赤霉病流行趋势预测及产量损失研究

采用相关分析和逐步回归方法对黑龙江省西北部小麦主产区赤霉病流行情况和气象因素间的关系进行分析,制定了适用于该地区非特殊灾变年份的小麦赤霉病流行趋势预测初始数学模型：Ｙ＝－５２６４８＋０４９５ｘ１＋０２７８ｘ２＋０１０１ｘ３±０９７１１,方程的历史回拟率为８７５％。通过田间接种试验,获得不同抗性品种不同发病程度的病穗率、病情指数和小麦产量的相关数据。经回归分析,得到了小麦赤霉病产量损失估计模型,中感型品种（龙麦１９）：ＹＭＳ＝００２４＋０７８１ｘ±６１２４,中抗型品种（龙８７－７９５３）：ＹＭＲ＝－００３３＋０６７９ｘ±７５０２。方程的复相关系数分别为０９９１１和０９８４７。历史拟合率为８８９％和８５７％。     

玉米弯孢菌叶斑病的初步研究简报

经作者分离接种鉴定，确认近年北京郊区和河北省的一些玉米产区发生的叶斑病为玉米弯孢菌叶斑病。病原菌是Ｃｕｒｖｕｌａｒｉａｌｕｎａｔａ。发生此病玉米可减产２０％～６０％，且有逐年加重的趋势。经人工接种鉴定不同品种（系）抗性不同，Ｍｏ１７、黄早四、丹３４０、４７８、５００３和Ｅ２８等骨干自交系均为感病类型（３～４级）。西玉３号、京早１０号不同生育期抗性不同，以３～４叶期为抗病类型（０．５级）、７～８叶期、１０叶期和抽雄期为中抗型（２级），１３叶期为感病型（３～４级）     

甘薯根腐病抗性在不同环境条件下的表现及遗传趋势

结果表明,甘薯根腐病发病轻重与环境条件有很大关系,表现为干旱少雨的年份发病较重,降雨量较多的年份发病较轻;土壤瘠薄的发病较重,肥力条件较好的则发病较轻;通常情况下,年份间品种的抗性表现较为一致,但遇特殊气候则年份间品种的抗性有一定的差异。对1150份甘薯品种资源及育种材料的根腐病抗性鉴定结果表明,高抗型材料占14.6％,抗病型占15.7％,感病型占26.0％,高感型占43.7％。对754份材料及亲本的抗性分析表明,不同的抗性组合后代中均可分离出高抗至高感类型的材料,杂交后代的抗性强弱随双亲抗性水平的提高而提高。中国自1970年以来采用品种间杂交和种间杂交育种技术,先后育成了一批高产、优质的高抗型优良品种。     

大麦赤霉病鉴定方法与抗性评价

为探讨以病小穗率与病穗率作为抗性评价指标的精确度,利用单花滴注、孢子液喷雾分别结合土表病麦粒接种的方法,评价了2个大麦重组自交系群体131个株系对赤霉病的抗侵染与抗扩展性。单花滴注接种后调查了第7、14和21天的病情性状,接种后第7天所有株系均感病,病小穗率最低的为1.59%,第21天最高病小穗率为58.91%;孢子液喷雾接种后第21天材料全部感病,其中6棱株系的感病程度高于2棱株系。以病小穗率和病穗率划分赤霉病抗性的分布情况,发现病小穗率更能有效区分株系的赤霉病抗性。相关分析显示,病小穗率、病穗率、禾谷镰刀菌烯醇含量与粒色和穗密度呈显著负相关,而与株高、抽穗期无显著相关。     

小麦品种对赤霉病的感病和抗病因素研究

 本文是报道小麦品种感染赤霉病的程度差异及其有关因素。
温室试验,在麦穗终花期分别对残留于颖外的花药;残留于颖内的花药;无残留花药的子房上,进行接种。三种处理的赤霉病发生量之比,浙麦1号(感病)为15:58:31,苏麦3号(抗病)为4:18:13。结果表明:品种间差异显著;两品种均以外露花药上接种的处理发病最轻,颖内接种.有残留花药发病加重,尤以浙麦1号为明显;两品种始病后的病情扩展速度有异,苏麦3号表现扩展慢、穗轴不受侵害。因此,一个品种的穗部全部颖花中残留花药比率低,是减缓初侵染病程的性状;小穗和穗轴组织减缓病情发展,是抗扩展性状。具备两者,则相对抗性较为稳定。
室内外对普通小麦品种不同成熟阶段的接种试验表明,抗病品种具有感病期短、乳熟期的抗性明显增强和接种后发病盛期较晚等特点。     

蓖麻灰霉病在广西发生简报

蓖麻灰霉病在广西过去虽有零星发生,但无正式报道。１９９８年６～７月,我们观察到该病在桂西、桂南一些山区连片蓖麻园严重发生,正处于开花座果的蓖麻发病株率达１００％,发病穗率达８４６％以上,且大都重度感染（笔者暂定：１级,有１～２个幼果发病的;２级,２个以上幼果发病的;３级,穗轴感染并已褐腐的）,病情蔓延发展迅速。　　经镜检,并经广西大学农学院陈育新教授鉴定,确定此病病原菌为半知菌亚门、丝孢纲,丝孢目、淡色菌科的葡萄孢属真菌。学名为灰葡萄孢（ＢｏｔｒｙｔｉｓｃｉｎｅｒｅａＰｅｒｓｅｘＦｘ）。其分…     

不同小麦品种(系)对赤霉病的抗性和麦穗组织中DON毒素积累分析

 为明确不同小麦品种(系)对赤霉病的抗性和麦穗组织中DON毒素积累水平,培育和利用抗赤霉病和DON毒素积累的品种提供资源和依据,本研究采用单小花滴注接种法对河南省的106个小麦品种(系)抗赤霉病性进行鉴定分析,并用ELISA测定了病穗组织中DON毒素水平。结果表明不同小麦品种(系)对赤霉病的抗性有显著差异,106个小麦品种(系)中未发现抗病和中抗材料,中感品种(系)有华育198、郑麦103和春丰0021等14个,占13.2%;感病的有曌式2010-06、百农898和中麦63等92个,占86.8%。不同小麦品种(系)籽粒、颖壳和穗轴中DON毒素积累水平有显著差异,籽粒中DON毒素水平在(0.70~287.63)mg/kg之间,其中郑03876、豫保1号和中麦63 的DON毒素水平在2 mg/kg 以下,为抗毒素材料;其他的103个品种DON毒素水平大于2 mg/kg;颖壳和穗轴中的DON毒素水平在(51.03~392.87)mg/kg之间,普遍比籽粒中DON毒素含量高。籽粒中DON毒素水平与小麦品种(系)的平均病害严重度间呈极显著正相关。     

小麦对黑胚病的抗性及黑胚对产量损失的影响

人工接种试验结果表明,在相同时间、地点、栽培技术和接种条件下,１６０份小麦品种（系）感染黑胚病的程度有差异。其中２５份抗病,１３５份感病,病粒率在０１％～５７６％之间。接种区籽粒和自然感病区相比,６０％品种（系）千粒重增加,４０％品种（系）千粒重降低,且千粒重增减与其病粒率高低无关。黑胚病影响小麦产量的主要原因是穗粒减少,千粒重降低。     

54个小麦品种(系)抗赤霉病评价与农艺性状调查

为获得抗赤霉病且农艺性状较好的小麦种质资源, 加快小麦抗赤霉病育种进程, 采用人工接种鉴定和田间试验的方法, 于2019年-2021年, 对54个小麦品种(系)进行了赤霉病抗性鉴定与农艺性状调查。结果表明, 供试小麦品种(系)存在赤霉病抗性差异, 筛选出‘华皖麦24’‘宛1204’和‘皖垦麦1708’等9个两年表现稳定的中抗品种(系), 占总数的16.67%; 农艺性状调查结果显示, 不同小麦品种(系)的农艺性状间存在显著性差异, 抗病组品种(系)的平均变异系数小于感病组品种(系)。其中, ‘宛1204’和‘徐麦17252’中抗赤霉病, 且综合农艺性状较好, 可以作为抗赤霉病育种的抗源。     

Expression of Endochitinase from Trichoderma harzianum in Transgenic Apple Increases Resistance to Apple Scab and Reduces Vigor

ABSTRACT The goal of this research was to improve scab resistance of apple by transformation with genes encoding chitinolytic enzymes from the bio-control organism Trichoderma harzianum. The endochitinase gene, as cDNA and genomic clones, was transferred into apple cv. Marshall McIntosh by Agrobacterium-transformation. A total of 15 lines were identified as transgenic by NPTII enzyme-linked immunosorbent assay and polymerase chain reaction and confirmed by Southern analysis. Substantial differences in endochitinase activity were detected among different lines by enzymatic assay and western analysis. Eight lines propagated as grafted and own-rooted plants were inoculated with Venturia inaequalis. Six of these transgenic lines expressing endochitinase were more resistant than nontransformed cv. Marshall McIntosh. Disease severity compared with cv. Marshall McIntosh was reduced by 0 to 99.7% (number of lesions), 0 to 90% (percentage of leaf area infected), and 1 to 56% (conidia recovered) in the transgenic lines tested. Endochitinase also had negative effects on the growth of both inoculated and uninoculated plants. There was a significant negative correlation between the level of endochitinase production and both the amount of disease and plant growth.     

广东省甘薯疮痂病病原菌鉴定及国内主要菜用甘薯种质抗性评价

为明确广东省甘薯疮痂病病原菌种类及当前国内主要菜用甘薯种质对疮痂病的抗性,结合形态学特征和rDNA-ITS序列分析对病原菌进行鉴定,并通过病圃诱发结合人工喷雾接种法对来自9个省区30个菜用甘薯种质进行连续2年的抗性鉴定。结果显示,共获得15株形态学特征及培养性状相似的菌株,其中代表菌株CRI-CJ的形态学特征与甘薯痂圆孢菌Elsinoe batatas基本一致,且在基于rDNA-ITS序列的系统发育树中与甘薯痂圆孢菌聚在一支,表明甘薯疮痂病病原菌为甘薯痂圆孢菌。30个菜用甘薯品种(系)中,抗性、中抗、中感和感病品种(系)分别为7、7、5和11个,占总数的23.3%、23.3%、16.7%和36.7%。其中抗性品种(系)有广菜薯11-52、广菜薯15-6、广菜薯16-1、广菜薯16-19、广菜薯17-23、广菜薯17-9和广菜薯18-6,中抗品种(系)有EC01、广薯菜2号、广菜薯3号、广菜薯6号、广菜薯7号、广菜薯17-25和广菜薯18-3。不同地理来源的品种(系)对甘薯疮痂病的抗性水平存在差异,11个非广东省品种(系)中感病、中感和中抗品种(系)分别为8、2和1个,占比分别为72.7...     

Effect of Trichothecenes Produced by Fusarium graminearum during Fusarium Head Blight Development in Six Cereal Species

Fusarium head blight (FHB) is a complex cereal disease associated with trichothecene production; these mycotoxins are factors of aggressiveness in wheat. Six species (bread and durum wheat, triticale, rye, barley and oats) were submitted to point inoculations with two isogenic strains of Fusarium graminearum; a wild strain (Tri5 +) produced trichothecenes and the mutated strain (Tri5 –) did not. The trichothecene-producing strain was generally more aggressive than the non-producing strain, but this varied according to crop species. The difference in aggressiveness was less pronounced in rye, a very resistant species. High resistance levels were observed in oats due to the large spacing between florets. In six-row barley, despite the existence of a moderate Type II resistance, the fungus was often observed to move externally from one floret to another within the dense spike, without penetrating the rachis. Bread wheat had low resistance to the trichothecene-producing strain and good resistance to the non-producing strain. Triticale responded to the strains in a similar way but was somewhat more resistant to both: symptoms on the spikelets and rachis of the triticales were restricted to below the point of inoculation. Durum wheat was susceptible to the trichothecene-producing strain and only moderately resistant to the non-producing strain, which was able to cause serious damage only to this species. Our study confirmed that the role of trichothecenes in FHB pathogenesis differs among species. The failure of the trichothecene non-producing F. graminearum strain to spread within the inflorescence of wheat, triticale, rye and barley, and the significant reduction of spread in the durum wheat spike strongly suggested that trichothecenes are a major determinant of fungal spread and disease development in Triticeae.     

Mapping Quantitative Field Resistance Against Apple Scab in a 'Fiesta' x 'Discovery' Progeny

ABSTRACT Breeding of resistant apple cultivars (Malus x domestica) as a disease management strategy relies on the knowledge and understanding of the underlying genetics. The availability of molecular markers and genetic linkage maps enables the detection and the analysis of major resistance genes as well as of quantitative trait loci (QTL) contributing to the resistance of a genotype. Such a genetic linkage map was constructed, based on a segregating population of the cross between apple cvs. Fiesta (syn. Red Pippin) and Discovery. The progeny was observed for 3 years at three different sites in Switzerland and field resistance against apple scab (Venturia inaequalis) was assessed. Only a weak correlation was detected between leaf scab and fruit scab. A QTL analysis was performed, based on the genetic linkage map consisting of 804 molecular markers and covering all 17 chromosomes of apple. With the maximum likelihood-based interval mapping method, eight genomic regions were identified, six conferring resistance against leaf scab and two conferring fruit scab resistance. Although cv. Discovery showed a much stronger resistance against scab in the field, most QTL identified were attributed to the more susceptible parent 'Fiesta'. This indicated a high degree of homozygosity at the scab resistance loci in 'Discovery', preventing their detection in the progeny due to the lack of segregation.     

Analysis of Accumulation Patterns of <Emphasis Type="Italic">Barley yellow dwarf virus-PAV</Emphasis> (BYDV-PAV) in Two Resistant Wheat Lines

Barley yellow dwarf (BYD) is one of the main viral diseases of small-grain cereals. This disease, reported on numerous plant species of the Poaceae family, is caused by a complex of eight viral species including the species Barley Yellow Dwarf Virus-PAV (BYDV-PAV), frequently found in western Europe. Resistance sources against BYDV-PAV are scarce and only identified in perennial Triticineae. Some BYDV-resistant wheat lines have been obtained by introgressing these resistances into bread wheat germplasms. Genetic and biological characterization of the resulting lines has been undertaken. However, little information on the resistant behaviour of these lines during the early stages of the infection process is available. To evaluate the resistance of two genetically distinct resistant lines (Zhong ZH and TC14), 1740 young plantlets, belonging to susceptible reference hosts (barley cv. Express and wheat cv. Sunstar), Zhong ZH or TC14 wheat lines, were inoculated in controlled conditions with French BYDV-PAV isolates. The infection process was monitored during the first 21 days after inoculation (DAI) using a semi-quantitative ELISA. A standardized protocol including five successive samplings of leaves from all inoculated plants and the collection of plant roots at the end of the monitored period was carried out. This protocol enabled an assessment of the infection percentage and the evolution of the viral load in plants from the 7th DAI to the 21st DAI. Statistical analyses of the BYDV infection kinetics using raw ELISA data, a model of the time-dependent variation of the percentage of infected plants and the area under concentration progress curves (AUCPC) demonstrated that Zhong ZH and TC14 lines (1) reduce the development rate of the BYD disease during the first days of infection, (2) decrease the infection efficiency of BYDV-PAV isolates, in the leaves, from 98.7% for susceptible plant genotypes to 81.9% and 71.7% for Zhong ZH and TC14, respectively, (3) reduce the virus load in the leaves of infected plants and (4) are not spared from BYDV infection, as 95.1% of Zhong ZH and 90.2% of TC14 inoculated plants accumulated viral particles in roots and/or in leaves at 21 DAI. These results confirm the BYDV-partial resistant behaviour of both Zhong ZH and TC14 lines. The development rate of the disease was the single parameter that allowed the distinction between the two resistant sources present in the tested lines.     

禾谷多粘菌分离、培养、接种及用于大麦抗黄花叶病的鉴定

 通过禾谷多粘菌Polymyxa graminis L.休眠孢子分离接种感病大麦品种,并进行砂培养,获得13个纯化了的禾谷多粘菌分离物,且其中3个带有大麦黄花叶病毒(BaYMV)。用分别带有BaYMV和大麦温和花叶病毒(BMMV)的英国禾谷多粘菌分离物的游动孢子接种13个中国大麦品种,以及用BaMMV摩擦接种36个中外大麦品种,抗性鉴定结果游动孢子接种与摩擦接种一样,均与田间鉴定结果一致,且大麦对BaYMV的抗性与对BaMMV的抗性一致,从而这2种接种方法可用于大麦品种(系)和育种中间体对BaYMV抗性的快速鉴定和筛选。游动孢子或休眠孢子接种方法还可有效地鉴定大麦对禾谷多粘菌的抗性。     

Application of real-time and multiplex polymerase chain reaction assays to study leaf blotch epidemics in barley

ABSTRACT Leaf blotch, caused by Rhynchosporium secalis, was studied in a range of winter barley cultivars using a combination of traditional plant pathological techniques and newly developed multiplex and real-time polymerase chain reaction (PCR) assays. Using PCR, symptomless leaf blotch colonization was shown to occur throughout the growing season in the resistant winter barley cv. Leonie. The dynamics of colonization throughout the growing season were similar in both Leonie and Vertige, a susceptible cultivar. However, pathogen DNA levels were approximately 10-fold higher in the susceptible cultivar, which expressed symptoms throughout the growing season. Visual assessments and PCR also were used to determine levels of R. secalis colonization and infection in samples from a field experiment used to test a range of winter barley cultivars with different levels of leaf blotch resistance. The correlation between the PCR and visual assessment data was better at higher infection levels (R(2) = 0.81 for leaf samples with >0.3% disease). Although resistance ratings did not correlate well with levels of disease for all cultivars tested, low levels of infection were observed in the cultivar with the highest resistance rating and high levels of infection in the cultivar with the lowest resistance rating.     

Amplified fragment length polymorphism markers linked to a major quantitative trait locus controlling scab resistance in wheat

ABSTRACT Scab is a destructive disease of wheat. To accelerate development of scab-resistant wheat cultivars, molecular markers linked to scab resistance genes have been identified by using recombinant inbred lines (RILs) derived by single-seed descent from a cross between the resistant wheat cultivar Ning 7840 (resistant to spread of scab within the spike) and the susceptible cultivar Clark. In the greenhouse, F(5), F(6), F(7), and F(10) families were evaluated for resistance to spread of scab within a spike by injecting about 1,000 conidiospores of Fusarium graminearum into a central spikelet. Inoculated plants were kept in moist chambers for 3 days to promote initial infection and then transferred to greenhouse benches. Scab symptoms were evaluated four times (3, 9, 15, and 21 days after inoculation). The frequency distribution of scab severity indicated that resistance to spread of scab within a spike was controlled by a few major genes. DNA was isolated from both parents and F(9) plants of the 133 RILs. A total of 300 combinations of amplified fragment length polymorphism (AFLP) primers were screened for polymorphisms using bulked segregant analysis. Twenty pairs of primers revealed at least one polymorphic band between the two contrasting bulks. The segregation of each of these bands was evaluated in the 133 RILs. Eleven AFLP markers showed significant association with scab resistance, and an individual marker explained up to 53% of the total variation (R(2)). The markers with high R(2) values mapped to a single linkage group. By interval analysis, one major quantitative trait locus for scab resistance explaining up to 60% of the genetic variation for scab resistance was identified. Some of the AFLP markers may be useful in marker-assisted breeding to improve resistance to scab in wheat.     

Infection of Rrs1 barley by an incompatible race of the fungus Rhynchosporium secalis expressing the green fluorescent protein

Scald disease of barley, caused by the fungal pathogen Rhynchosporium secalis, is one of the most serious diseases of this crop worldwide. Disease control is achieved in part by deployment of major resistance (Rrs) genes in barley. However, in both susceptible and resistant barley plants, R. secalis is able to complete a symptomless infection cycle. To examine the R. secalis infection cycle, Agrobacterium tumefaciens‐mediated transformation was used to generate R. secalis isolates expressing the green fluorescent protein or DsRed fluorescent protein, and that were virulent on an Rrs2 plant (cv. Atlas), but avirulent on an Rrs1 plant (cv. Atlas 46). Confocal laser scanning microscopy revealed that R. secalis infected the susceptible cultivar and formed an extensive hyphal network that followed the anticlinal cell walls of epidermal cells. In the resistant cultivar, hyphal development was more restricted and random in direction of growth. In contrast to earlier models of R. secalis infection, epidermal collapse was not observed until approximately 10 days post‐inoculation in both cultivars. Sporulation of R. secalis was observed in both susceptible and resistant interactions. Observations made using the GFP‐expressing isolate were complemented and confirmed using a combination of the fluorescent probes 5‐chloromethylfluorescein diacetate and propidium iodide, in the non‐transformed wild‐type isolate. The findings will enable the different Rrs genes to be better characterized in the effect they exert on pathogen growth and may aid in identification of the most effective resistance.