稻曲病的接种技术研究

 探索在田间条件下进行稻曲病的人工接种技术。通过比较3种接种体发现,上年保存于-20℃的厚垣孢子不能引起发病;用PS液体培养获得的薄壁分生孢子可引起发病,孢子浓度越高引起病穗率越高;菌丝片段-分生孢子混合液接种发病最严重。病原菌的培养菌龄对接种效果有影响。在水稻的3个时期接种,以抽穗破口前6~9d的效果最好。在一天的3个时段接种,以下午4~6时的病情最重。在接种液里添加马铃薯煮汁可显著提高接种发病率。本文的接种技术能高效引发稻曲病,最高穗发病率100%,最大病情指数93.96,最多穗病粒数110粒。该接种技术可鉴别出品种抗病性的差异。     

水稻稻曲病不同发病模式对水稻产量影响观察

2014—2015年,以南粳9108水稻品种为观察对象,研究了稻曲病不同发病模式对水稻产量的影响。结果表明,稻曲病发病后,水稻千粒重、结实率随每穗病粒数增加而降低,产量损失率随每穗病粒数增加而增加。未发病籽粒所受影响以稻曲病病粒所在一次枝梗受影响最大,其他位置距离病粒越近受影响越大,且病粒下部籽粒所受影响大于病粒上部籽粒;随稻曲病病粒在水稻穗部位置的上升,其对其他未发病籽粒影响也存在不同程度的增加。田间平均每穗病粒数随稻曲病病穗率提高而增加。     

稻曲病产量损失测定及调查测报因子研究

稻曲病是水稻穗部的重要真菌性病害。本研究分析了13个供试水稻品种每穗稻曲病病粒数与水稻产量损失的线性关系,根据每个品种线性方程及南方稻区实际情况,得出了田间稻曲病经济允许水平、成灾因子,即平均每穗病粒数分别为0.57、5.44粒。     

水稻穗部农艺性状与稻曲病抗性的相关性分析

 人工接种试验和田间多年自然发病调查发现,目前生产上应用的水稻品种均感稻曲病;但在自然条件下,不同水稻品种稻曲病的发生程度存在较大差异,可以人为的分为多病粒高感品种和寡病粒相对抗病的品种。为了探究水稻穗部性状与其病害抗性间的关系,本文对孕穗期不同阶段的不同水稻品种的穗部性状进行了比较分析。结果发现表型为多病粒的高感多病粒品种与表型为寡病粒的相对抗病的品种之间在穗子大小、小花密度、穗鞘闭合程度和密封性、旗叶面积等方面均存在明显差异,寡病粒相对抗病的水稻品种穗鞘闭合程度优于高感多病粒品种。     

2014年江汉平原水稻稻曲病促病气象条件指数分析

以华中江汉平原地区荆州市中稻为研究对象,2014年选择广两优香66、丰两优香1号籼型两系杂交水稻品种和宁9108常规粳稻品种为供试品种,采取传统水育秧人工移栽、机插秧、直播3种栽培方式。每种栽培方式分3期播种。在水稻黄熟期调查总穗数、稻曲病自然发病病穗数和每穗病粒数,计算病穗率和病情指数。在稻曲病感病关键生育期孕穗至齐穗期气象要素与稻曲病病穗率相关分析基础上,从稻曲病发生机理出发,筛选满足稻曲病病菌侵入寄主繁殖流行的气象因子条件,即水稻稻曲病的促病气象指标:日平均气温20~28℃,日平均空气相对湿度≥80%,日降水量≥0.1 mm(或日照时数≤1 h),建立了稻曲病促病气象条件指数。促病气象条件指数与稻曲病病穗率、病情指数的相关性分析结果均通过了1%水平显著性检验。在相关分析的基础上确立了稻曲病发生发展气象条件预报等级指标。     

稻曲病菌厚垣孢子侵染时期和侵染途径的研究

用田间自然发病病粒上新形成的稻曲病菌厚垣孢子,喷雾或注射接种不同生育期的稻穗获得成功。水稻孕穗末期至破口期是稻曲病菌厚垣孢子侵染的主要时期。在孕穗末期喷雾接种2次萌发孢子的发病率高达50.8%。解剖736个病粒内部都含有花药,镜检119条花药和35个柱头发现,病粒内大多数花粉粒的内容物已基本充实,柱头大多处于分枝状突起阶段。解剖刚发病的病粒柱头上有多根菌丝,并向花药等处扩展。萌发的厚垣孢子可以侵染处于乳头状突起期的柱头,并形成菌丝及产生小孢子。稻曲病菌厚垣孢子主要在水稻破口前1—4天至破口时从水稻的柱头侵入引起发病。     

2004年阜南县水稻稻曲病暴发流行

2004年阜南县水稻稻曲病暴发流行,给水稻生产造成严重损失。1发生特点1)流行面广,发病率高。全县2.1万hm2水稻,有1.6万hm2发病。其中严重发病田块占水稻种植面积的50%以上。发病田块病穗率平均31.8%,严重的70%～100%;病粒率平均4.37%,最高达54.0%。2)感病品种较多。生产上大面积推广的水稻主要品种均受到不同程度的为害,尤其是新品种粤优938受害损失严重,个别田块基本绝收。从田间调查结果看,一般高感病品种(如粤优938)病穗率达70%～80%,病粒率15.2%;严重田块病穗率达90%～100%,病粒率达54%;中感病品种(如Ⅱ优725)病穗率为40%;病粒率平均为1…     

稻曲病菌无性孢子萌发及在不同培养基上生长特性

采用不同的培养基研究稻曲病菌孢子萌发及病菌生长特性.结果表明,稻曲病菌厚垣孢子和分生孢子在蒸馏水和2%蔗糖溶液中3h不能萌发;6h时分生孢子、厚垣孢子分别萌发产生次生分生孢子和分生孢子;新采集的黄色和黑色稻曲球上的厚垣孢子在2%蔗糖溶液中的萌发率均高于其在蒸馏水中的萌发率.供试的9种固体培养基中,以马铃薯蔗糖琼脂培养基(PSA)最适于病原菌生长.生长速率为2.54 mm/天;病菌在7种培养液中振荡培养7天后,在马铃薯葡萄糖培养液(PDB)中菌丝干重最大,达24.5mg/mL,在大米汁和马铃薯蔗糖培养液(PSB)中产生的分生孢子量最多,孢子浓度分别为2.63×107和2.28×107个/mL;而固、液态的Czapek、稻秆汁和胁本哲氏培养基均不适宜于稻曲病菌的培养.     

籼型杂交水稻对稻曲病的田间抗性差异

为了解不同水稻品种在田间的抗性差异及其与农艺性状的相互关系,在相同的土壤环境和栽培条件下,利用稻曲病菌诱发接种鉴定,对56个籼型杂交水稻进行田间抗性差异比较,初步探讨了抽穗期和农艺性状与品种田间抗性的关系.结果表明,不同水稻品种对稻曲病田间抗性存在显著差异,病穗率为0.43%～33.04%,病情指数为0.05～16.14;不同抽穗期的品种稻曲病发病率不同,同一抽穗期的品种对稻曲病的抗性亦表现出明显差异;水稻株高与品种抗性之间呈正相关,相关系数为026(P<0.05);水稻分蘖率、有效穗数、剑叶性状等与品种的田间抗性有一定相关性,但差异不显著(P>0.05);水稻株叶形态和叶色与品种田间抗性没有直接相关性.     

来源于同一穗不同稻曲球的稻曲病菌的致病性及遗传多样性

 本研究从源于6穗稻曲病穗的48个稻曲球中分离获得稻曲病菌（Ustilaginoidea virens）48株,从3个稻曲球的不同部位分离获得稻曲病菌23株。用注射接种法将菌株分别接种到水稻品种两优培九（感病品种）、淮稻5号（中抗品种）和武育粳3号（抗病品种）上,结果显示分离的菌株致病力分化较大,而菌株在水稻品种上的致病力强弱与已知水稻品种对稻曲病菌的感、抗性趋势基本一致。相同孢子量接种水稻,不同分离菌株之间仍有致病力分化,生长速率测定也发现菌株之间可能存在差异。利用REP PCR (repetitive extragenic palindromic sequence PCR)技术进行菌株遗传多样性分析表明,同穗不同稻曲球分离的菌株中,1号穗分离的4个菌株聚在同一簇群,其余5穗的菌株分别聚在3～5个簇群;同一稻曲球不同部位分离的菌株中,一个稻曲球分离的8个病菌聚在同一簇群,而其余2个稻曲球分离的病菌则分别聚在2～3个簇群。由此推测同一稻穗上不同稻曲球可能是由来源不同的稻曲病菌侵染所形成;而一个稻曲球可以由同一稻曲病菌引起,也存在多个侵染源共同侵染的可能。     

Infection processes of Ustilaginoidea virens during artificial inoculation of rice panicles

Ustilaginoidea virens is a ubiquitous plant pathogen that causes rice false smut disease, one of the most destructive diseases of rice (Oryza sativa L.) production. However, data concerning the effect of inoculation on disease development and the infection process of this pathogen are not comprehensive. In this study, the developmental processes of U. virens in rice panicles were characterized using an enhanced green fluorescent protein (EGFP) labelled strain. A mixture of hyphae and conidia of U. virens was used to inoculate rice panicles by leaf sheath injection during the booting stage of rice plants grown in a greenhouse. The panicles were assessed to determine the relationship between artificial inoculation and disease occurrence. Increasing volumes of inocula (0.2, 0.5, 1, and 2 ml of a mixture of hyphae-fragment and 2?×?10⁶ conidia/ml suspension) caused more severe infections, and small differences were also observed for the different inoculation sites at the base, apex and mid-point of rice panicles. The optimum inoculation condition was 1–2 ml inoculum injected into the mid-point of rice panicles. Spikelet samples were collected as the disease progressed and observed by confocal laser scanning microscopy and scanning electron microscopy. The images collected showed that the primary site of U. virens colonization was at the base of the filaments with the inner spikelets becoming infected by hyphae at 24 h post inoculation (hpi). The accumulation of hyphae reached its highest level at 168 hpi, before the rice heading stage, as the infection extended upward from basal filaments to the anther apex, and then enclosed all the floral organs to produce a velvety smut ball.     

Epiphytic colonization of Ustilaginoidea virens on biotic and abiotic surfaces implies the widespread presence of primary inoculum for rice false smut disease

Ustilaginoidea virens (Uv), the causative agent of rice false smut disease, infects developing rice spikelets at the booting stage, and transforms individual grains of the panicle into smut balls. Epidemics of the disease occur when the rice booting and heading stages coincide with rainy days. Using a green fluorescent protein (GFP)‐labelled Uv isolate that can form false smut balls on rice panicles, it was found that under high humidity and free water conditions the Uv isolate could colonize leaves of plants belonging to various families including the Poaceae (Oryza sativa, Echinochloa crusgalli, Digitaria sanguinalis and Leptochloa chinensis), the Brassicaceae (Arabidopsis thaliana) and the Solanaceae (Nicotiana benthamiana) without symptoms. Over several days, some conidia could germinate on the leaves of these plants and in water on the surface of Parafilm and cellophane, form hyphae and differentiate conidiophores to generate a large number of secondary conidia, while other conidia were able to directly produce secondary conidia. Conversely, in the absence of water some conidia could either bud to form new conidia or were converted into chlamydospores. These data indicate that Uv is one of a few fungal pathogens reported to have epiphytic characteristics. The rapid generation of a large number of spores on biotic and abiotic surfaces greatly increases the inoculum that can infect rice spikelets, resulting in the occurrence of rice false smut disease epidemics. These findings are important in the development of disease control strategies.     

稻瘟病为害损失研究

采用人工接种诱发和药剂控制相结合的方法,造成小区间稻叶瘟病和稻穗瘟的发病梯度系统监测病情,收获期结合病情程度进行单株考上区测产,并分别建立了依据稻叶瘟病,稻穗瘟病和二者综合的损失估计模型。就稻叶瘟病地水稻有效穗、穗粒数、千粒重和精米率的影响作了定量研究。另外,地稻穗瘟病在不同品种,不同侵染发病时间以及不同发病部位的为害影响进行了初探。结果表明,稻穗瘟病的为害程度在不同品种上存在一定差异,与侵染发病     

水稻穗腐病病菌致病性、发生规律及防控技术研究

穗腐病是近年发生危害严重的水稻穗部病害.本研究对穗腐病的发生、流行原因进行了分析,分离了病原菌并测定了致病性,筛选了防治该病的杀菌剂并进行了田间防效试验.结果表明,紧穗型的粳稻及籼/粳杂交稻组合较穗型松散的籼稻及其杂交组合更易感病.水稻孕穗后期-抽穗扬花期遇阴雨高湿、温暖天气该病发生危害重.用分离到的4个菌(层出镰刀菌、澳大利亚平脐蠕孢菌、新月弯孢菌和细交链孢菌)进行人工接种,均能使稻粒感病,初步确定层出镰刀菌为主要初侵染菌.室内抑菌测试结果显示,5 mg/L以上浓度的多菌灵、咪鲜胺和苯醚甲环唑·丙环唑(爱苗)对层出镰刀菌生长的抑制效果达到81.31％～100％.抑制中浓度为0.000 7～0.947 6 mg/L.田间试验结果表明,在水稻孕穗后期和抽穗扬花期用三唑酮、多菌灵或甲基硫菌灵喷雾防治一次,防效在70％左右.     

Comparison between the resistance to blast in panicles exserted from the main culm and primary tillers as measured in six rice varieties

Three rice japonica varieties Jiajing3768, Xiushui09, and Xiushui63 and three rice indica varieties Qianyou930, Liangyoupeijiu, and Liangyou6326 were used to analyze the resistance to neck blast, comparing panicles excised from the main culm and from the first primary tiller. Disease incidence in the necks, disease incidence in the rachis nodes, lesion length in the necks, and number of conidia in the necks were measured after artificial inoculation of excised neck pieces. Resistance to neck blast was higher in the panicles excised from the main culm than from the first primary tiller for the varieties Jiajing3768, Xiushui63, and Liangyou6326. However, the opposite was true for Xiushui09 and Liangyoupeijiu. In Qianyou930, the type of panicles had no significant influence on the resistance to neck blast.     

安徽省稻曲病气象等级预报方法研究—以池州为例

为进一步明确安徽省稻曲病发生关键期, 探索稻曲病气象等级预报方法, 以满足对该病害气象等级预报的服务需求?本文以安徽省池州市为例, 利用1995年-2018年一季稻稻曲病观测数据和同期气象资料, 通过相关分析确定稻曲病发生关键期?根据稻曲病大发生对适温高湿环境的需求及不同降水等级和温度对稻曲病发生程度的影响不同, 以稻曲病发生关键期降水日数为基础, 引入雨量系数和温度系数, 形成稻曲病发生综合气象条件指数, 通过最优曲线回归分析, 建立稻曲病预报模型?结果表明, 7月下旬至8月中旬是池州市一季稻稻曲病发生关键期; 综合气象条件指数与稻曲病病穗率相关性明显高于降水日数与病穗率相关性; 预报模型回代检验准确率为81.0%, 2016年-2018年模型预测结果均与实际情况相吻合, 由于样本中轻发生和大发生年份较少, 对轻发生和大发生预报的准确性需在样本丰富条件下进一步验证?模型在业务应用中, 可结合CFSv2模式逐日降水和气温预报产品, 提前10~30 d开展稻曲病气象等级预报, 对做好稻曲病的防治工作具有重要参考价值?     

水稻穗褐变病主要病原菌侵染时期及致病力研究

为了解黑龙江省水稻穗褐变病主要病原菌侵染时期及致病性情况,分别于水稻破口期、扬花期、乳熟初期采用禾谷镰孢Fusarium graminearum、链格孢Alternaria alternata、稻黑孢Nigrospora oryzae、黑附球霉Epicoccum nigrum对水稻穗进行注射和喷雾接种。结果表明,4种病原菌在水稻破口后即可侵染稻穗使谷粒颖壳变褐。注射接种稻穗谷粒褐变重于喷雾接种。4种病原菌的致病力存在明显差异,禾谷镰孢致病力最强,链格孢的致病力弱于禾谷镰孢。     

Induced Resistance to Rice Blast by Antagonistic Bacterium, <Emphasis Type="Italic">Serratia marcescens </Emphasis>Strain B2

An antagonistic bacterium, Serratia marcescens strain B2, controlled rice blast after being sprayed onto rice phylloplane, as did the bacterial suspension when poured into rhizosphere soil of rice plants. Three days after root treatment, rice blast conidia were sprayed onto rice foliage. A week after pathogen inoculation, rice blast was suppressed and lesions caused by the pathogen decreased in size. Brown deposits were observed around sites of pathogen infection after root treatment. Induced resistance was not associated with an increase in the activitiy of peroxidase, phenylalanine ammonia lyase, tyrosine ammonia lyase, β-1,3-glucanase, β-1,4-glycosidase, N-acetylhexosaminidase or chitinase. However, lipoxygenase levels were elevated after the root treatment with strain B2 following inoculation with the pathogen. Strain B2 was not detected in rice foliage after root treatment. These data suggest that strain B2 induced resistance against rice blast caused by Pyricularia oryzae. Received 1 November 2001/ Accepted in revised form 25 January 2002