甜菜褐斑病菌致病力的研究

1987～1988年在3个病圃试验,10个不同地区的甜菜褐斑病分离菌对25个品种(系)的致病力测定结果看出,不同地区分离菌在不同品种(系)上、不同地区分离菌在同一品种(系)上、单一分离菌在不同品种(系)上致病力均存在差异,有的表现差异显著或极显著。但这种差异表现无规律或不稳定。因此初步认为,甜菜褐斑病菌致病力虽存在差异,但生理分化作用不明显。     

江苏省油菜菌核病菌对多菌灵的敏感性

为监测目前油菜菌核病菌对多菌灵抗性现状，对从江苏省各地采集的油菜菌核病病原菌菌株以及海安、苏州和高淳三地的油菜菌核病病原菌田间群体菌株进行了多菌灵的敏感性测定。结果表明，江苏省油菜菌核病菌对多菌灵的抗药性已经产生，不同地区菌株对多菌灵的抗性比率不同。在苏州的田间菌株群体中抗性菌株的比率达到28.12%，而在高淳等地的菌株中没有检测到抗性菌株的存在。抗性菌株都表现为高抗，其EC50 >100µg／ml。对抗性菌株的β-微管蛋白基因进行PCR扩增和酶切的结果表明，所有抗性菌株的β-微管蛋白基因的198位都发生突变，从而导致油菜菌核病菌对多菌灵抗性的产生。从江苏省范围来看，继续使用多菌灵防治油菜菌核病菌可能会导致抗性频率上升、抗性范围扩大。     

五种杀菌剂对花生褐斑病菌室内毒力的影响和田间药效

为了筛选对花生褐斑病田间防治效果好的杀菌剂,结合室内毒力测定(菌丝生长速率法和载玻片萌发法)和田间小区药效试验对四种杀菌剂与常规使用的杀菌剂多菌灵进行了比较。结果表明,室内毒力测定中,多菌灵对菌丝的抑制效果最强,抑菌率为91.4%;其余四种供试杀菌剂中以咪酰胺效果最好,抑菌率达85.6%;王铜效果最差;多菌灵对分生孢子的抑制率为60.9%,其余四种杀菌剂效果差异不显著。田间药效试验结果显示,咪酰胺2 000mg/kg对花生褐斑病的田间防治效果达60.62%,远远高于对照药剂多菌灵(15.53%)以及其它三种供试杀菌剂(王铜、爱可和戊唑醇)。此外咪酰胺比清水对照增产32.28%,也远远高于其它几种药剂。通过室内毒力试验和田间药效试验表明,田间杀菌剂防治花生褐斑病时,咪酰胺比对照药剂多菌灵具有更好的防治效果,适用于花生褐斑病重病地区。     

玉米尾孢菌、弯孢菌叶斑病严重流行及防治对策

近几年来,由于气候适宜和感病品种多年的大面积种植,导致我国玉米种植区的玉米尾孢菌、弯孢菌叶斑病的危害越来越重,辽宁、河北、河南等地均有发生,尤以辽宁发生最为严重,一般减产10%～20%,个别地块的感病品种几乎绝产,所以必须引起高度重视,应以推广抗病品种为重点,采取合理的品种布局及药剂防治等进行综合防治。     

Sensitivity to iprodione, difenoconazole and fludioxonil of Rhizoctonia cerealis isolates collected from wheat in China

Since the 1980s wheat sharp eyespot (WSE) caused mainly by Rhizoctonia cerealis has become one of serious diseases of wheat in China. In this study, the sensitivity of 89 R. cerealis isolates to different fungicides was evaluated using mycelial growth inhibition assays. The results showed that all R. cerealis isolates tested were sensitive to iprodione, difenoconazole and fludioxonil with mean EC₅₀ (effective concentration that results in 50% of mycelial growth inhibition) values of 0.419, 0.062 and 0.033 μg/ml, respectively. To evaluate the risk of fungicide resistance in R. cerealis, an attempt was made to induce resistant mutants in the laboratory. Although difenoconazole- and fludioxonil-resistant mutants were not obtained, we obtained seven independently iprodione-resistant (IR) mutants from 89 parental isolates. The EC₅₀ values for these IR mutants were greater than 100 μg/ml, whereas those for the original wild-type counterparts were less than 1 μg/ml. After having been subcultured on PDA for 10 generations, the IR mutants did not show any decrease in resistance to iprodione. Additionally, these IR mutants also showed resistance to fludioxonil but remained sensitive to difenoconazole. Osmotic sensitivity tests showed that the IR mutants were hypersensitive to osmotic stress generated by NaCl. Inoculation tests showed that all the IR mutants lost their ability to infect the host plant. Taken together, these results indicate that the current population of R. cerealis is sensitive to these fungicides and a fitness cost is associated with iprodione-resistant mutants of R. cerealis in both osmotic stress and pathogenicity. The information obtained in this study is useful in monitoring and managing fungicide resistance in R. cerealis populations in China.     

Influence of fungicide spray schedules on the sensitivity of Cercospora beticola to the sterol demethylation-inhibiting fungicide flutriafol

A field experiment was conducted over a three-year period (1997–1999) to study the efficacy of several fungicide spray-schedules and their effects on the sensitivity of Cercospora beticola populations to the DMI fungicide flutriafol. Spray applications of flutriafol, either alone at the recommended dose, or at a reduced dose in mixtures with maneb, or in alternation with tank mixed fentin-acetate and maneb, were included in the spray programs. Applications of flutriafol at the recommended dose showed a significantly greater control efficacy in comparison with the other treatments, while applications of flutriafol alternated with tank mixed fentin-acetate and maneb showed lower efficacy in comparison with the remaining flutriafol treatments. Fungal populations from plots continuously treated with flutriafol, either alone at the full dose or at reduced dose with maneb, had lower sensitivity to flutriafol in comparison with populations from plots treated alternatively with flutriafol and tank mixed fentin-acetate and maneb. Repeated applications of flutriafol, at full or reduced doses, favoured the selection of highly resistant strains. Since applications of flutriafol in alternation with tank mixed fentin-acetate and maneb do not maintain a high level of disease control, the only available anti-resistance strategy would be the restriction of the number of flutriafol treatments, by applying them only when environmental conditions are favourable for disease development and by using alternative fungicides during the rest of the growing season.     

不同品种甜菜褐斑病抗性分析及早期鉴定方法

采用人工病圃和自然病田同步进行抗褐斑病性鉴定筛选,初步试验结果表明,甜菜品种的含糖率随着抗病性的增强而明显提高,凡抗褐斑病品系材料,综合性状表现也较好。通过3期播种试验,植株生长至2～4对真叶期接种鉴定抗褐斑病性与田间成株鉴定结果相同,可以作为田间鉴定育种新材料的一种简便易行的方法。玛纳斯人工接种的最佳时间7月中下旬接种效果较理想,这为解决干旱地区抗病品种筛选鉴定提供了一条途径。利用甜菜褐斑病尾孢毒素粗提液对甜菜种子胚根生长的抑制作用,鉴定不同品种的抗病性,试验结果显示,各品种抗性结果与人工接种及自然病田抗性鉴定结果有一致性。试验表明采用早期鉴定方法,方法准确,可行性高,可以提高育种效率,有效缩短抗褐斑病育种进程。     

300份玉米种质对两种灰斑病菌的抗性评价

2013～2016年,采用田间人工接种方法,评价300份玉米种质对两种灰斑病菌玉米尾孢(Cercospora zeina)和玉蜀黍尾孢(Cercospora zeae-maydis)的抗性。结果表明,对玉米尾孢表现高抗、抗和中抗的种质分别为10、100和121份,表现感和高感的种质分别为62份和7份;对玉蜀黍尾孢表现高抗、抗和中抗的种质分别为4、33和78份,表现感和高感的种质分别为137份和48份。76.99%的供试种质对玉米尾孢表现为高抗、抗或中抗,61.67%的供试种质对玉蜀黍尾孢表现为感或高感,玉米尾孢对大多数种质的致病力较玉蜀黍尾孢弱。     

Race distribution and distribution of sensitivities to mefenoxam among isolates of Phytophthora parasitica var. nicotianae in Guizhou province of China

Black shank, caused by the hemibiotrophic oomycete Phytophthora parasitica var. nicotianae, is a major disease of tobacco (Nicotiana tabacum) in southwest China. Mefenoxam is one of the most commonly used fungicides for its management. A survey was conducted to determine the level of mefenoxam sensitivity in the pathogen population in Guizhou province and to determine the race distribution of selected isolates. In 2012, 179 isolates of P. parasitica were screened for sensitivity to mefenoxam on lima bean agar. Zero percent of the isolates was classified as resistant, 41.9% as intermediately resistant, and 58.1% as sensitive. Race was determined for 32 isolates from 12 tobacco districts using five discriminative cultivars: NC-1071, Fla 301, L8, Xiaohuangjing 1025 and K-326. Twenty seven isolates were race 1 and five were race 0. Race 1 was present in all regions sampled and presents a major concern for the use of tobacco cultivars in Guizhou province in the future. Based on the results of our survey, we conclude that a combination of practices that includes partial resistance, cultural controls, and fungicides will be needed for long term management of tobacco black shank in Guizhou province of China.     

2006～2010年黑龙江省大豆灰斑病菌生理小种监测及部分主栽品种抗性鉴定

通过对2006～2010年黑龙江省大豆灰斑病生理小种的监测,明确了大豆灰斑病生理小种出现频率和分布情况.结果表明:1号生理小种在各大豆产区出现频率最高,为50.5%,平均为40.1%;其次是7号,出现频率为35.9%,平均为26.2%.出现频率较高的还有6、10和11号生理小种,平均出现频率分别为18.8%、12.0%...     

不同甜菜品种对褐斑病的抗性分析

2011-2013年对新疆伊犁地区甜菜褐斑病发生情况进行了调查,试验依据田间自然发病的抗性分析方法,对35个品种（品系）进行了抗性分析,发现发病前期有24个品种（品系）表现为中抗,占供试品种的68.57%,其余均表现感病。但在病害高峰期该24个品种（品系）抗性发生变化表现为感病,其余11个品种抗性变化不明显仍表现感病。35个品种在病害高峰期时均表现为感病,但部分品种的病情指数之间有显著性差异,表现为高感和中感。     

Reduced efficacy of rovral and botran to control Sclerotinia minor in lettuce production in the Salinas Valley may be related to accelerated fungicide degradation in soil

Accelerated soil degradation with repeated application was suggested to be responsible for the lack of efficacy of commercial fungicides to control lettuce drop caused by Sclerotinia minor in the Salinas Valley in California. In 2000, a study was initiated in a field artificially infested with S. minor to evaluate the efficacy and degradation potential of four selected fungicides (i.e., Rovral, Botran, Switch, and Endura). Crisphead lettuce was direct-seeded twice a year (spring and fall season) from 2000 to 2002. Fungicides were applied at recommended label rates twice during each season. Disease incidence was evaluated in fungicide treatments and nontreated control plots weekly starting immediately after thinning until harvest, and areas under the disease progress curves (AUDPC) were compared between treatments from 2000 to 2002. Soil samples (0–15 cm) were collected at regular intervals during the spring and fall 2002 lettuce seasons, and analyzed for residual fungicide concentration. Disease progress and final disease incidence were significantly affected by the fungicide treatment, season, year and interactions among these factors (p < 0.05). At the end of the three year experiment, up to 18 and 50% of the lettuce was infected by S. minor for the spring and fall seasons, respectively. Fungicide efficacy to control lettuce drop was highest for Endura, followed by Switch and Botran, and lowest for Rovral. Relative persistence in soils was lowest for Rovral and Botran, followed by Switch and Endura. In 2002, residual soil fungicide concentrations were 11% for Rovral and Switch, 23% for Botran, and 88% for Endura relative to their initial concentrations. Results of this study provide first evidence suggesting that reduced efficacy of lettuce drop control from Rovral and Botran in the Salinas Valley may be related to an accelerated degradation of these fungicides due to repeated application. However, insufficient fungicide persistence due to inherent properties of this sandy loam soil or the chemical structure of these fungicides can not be excluded. Both hypotheses deserve further investigation.     

花生晚斑病抗性育种研究进展

花生晚斑病是世界上危害最重、分布最广的花生真菌性病害之一。近三十年来在世界主要花生产区的危害逐渐加重,已成为制约花生品质、产量和经济效益的重要因素。本文综述了已育成抗晚斑病品种和品系、抗性遗传机制、抗病候选基因、数量性状基因座及分子标记和转基因抗性的研究现状,展望了未来花生晚斑病抗性育种的研究方向,为花生晚斑病抗性育种提供参考。     

Multiple-fungicide resistance to carbendazim,diethofencarb, procymidone,and pyrimethanil in field isolates of Botrytis cinerea from tomato in Henan Province,China

Botrytis cinerea, the fungal pathogen responsible for causing gray mold in tomatoes, frequently exhibits multiple fungicide resistance. In this study, the sensitivity to carbendazim (Car), diethofencarb (Die), procymidone (Prc), and pyrimethanil (Pyr) was determined for 263 isolates of B. cinerea from diseased fruit and leaves of tomato plants from 87 commercial greenhouses in Henan Province of China during 2013 and 2014. Of the isolates tested, 89%, 93%, 85%, and 86% were resistant to Car, Die, Prc, and Pyr, respectively. Twelve phenotypes were found having different sensitivity patterns, and multi-fungicide resistance was found to one, two, three or four fungicides. The percentage of multiple fungicide resistant isolates (Car^RDie^RPrc^RPyr^R) was 68%. Mycelial growth, spore production, and mycelial dry weight were not significantly different between resistant and sensitive phenotypes of the B. cinerea isolates. However, the virulence of Car^SDie^RPrc^SPyr^S isolates was higher than that of the other fungicide-resistance phenotypes. All of the carbendazim and diethofencarb resistant phenotypes carried a point mutation at codon 198 (E198A or E198K) or 200 (F200Y) in the β-tubulin gene, and all of the procymidone resistant phenotypes carried point mutations at codons 369 (Q369P) and 373 (N373S) in the Bos1 gene. These results provided important reference data for assessment of resistance risk of B. cinerea isolates from commercial tomato transplants in Henan Province, indicating the existence of a high frequency of resistance to carbendazim, diethofencarb, procymidone, and pyrimethanil revealing the necessity of a more integrated control of gray mold.     

高粱种质资源抗高粱靶斑病鉴定与评价

1996～1999年在田间人工接种诱导发病的条件下，对1476份高粱种质资源和40个高粱杂交种或杂交组合进行了抗高粱靶搬病抗性鉴定。从中鉴定筛选出419份抗高粱靶搬病的种质资源，9个高抗和7个抗高粱靶搬病的高粱杂交种或杂交组合。     

大豆品种感染灰斑病前后可溶性糖含量的比较

对大豆灰斑病抗病品种和感病品种在接种灰斑病菌前后可溶性糖含量的变化进行了比较研究。试验结果表明，接种前，抗感灰斑病品种可溶性糖含量并无明显差别；接种后，抗病与感病品种的可溶性糖含量均呈增加趋势，且感病品种可溶性糖含量的增加量大于抗病品种可溶性糖含量的增加量。     

花生晚斑病抗性AFLP标记

以抗感晚斑病组合“中花5号×ICGV 86699”的F2分离群体为材料，经田间抗性鉴定明确抗性亲本ICGV 86699的抗性受隐性单基因或主效基因控制；AFLP分析结合BSA法筛选到与晚斑病抗性连锁较紧密的AFLP标记3个，即E35/M51、E37/M48和E41/M47，它们与抗性间的图距分别为7.40cM、7.40cM和8.67cM；所获得的3个标记间连锁紧密，位于同一连锁群上。这3个标记在具有野生种亲缘的7个抗病花生品种或材料中均能检测到，而在栽培种以多粒型为代表的抗病材料中均未检测到，表明ICGV 86699的抗性基因与栽培种花生中的抗性基因不同。这是国内外有关花生晚斑病抗性分子标记的首例报道。     

北方产区花生品种黑斑病抗性鉴定

为筛选花生黑斑病抗源材料,以50个花生品种为材料,在山东省莱西市田间开展黑斑病抗性调查,并在温室条件下对其中7份材料进一步开展抗性鉴定。结果表明,不同花生品种在田间对黑斑病抗性存在差异,共获得4份中等抗病材料;在温室接种条件下,3份材料鉴定为中等抗病。综合田间自然发病和温室人工接种鉴定结果,获得冀农G94、豫花47号和晋花10号3份中抗黑斑病的材料。     

Sensitivity to fluopicolide of wild type isolates and biological characteristics of fluopicolide-resistant mutants in Pseudoperonospora cubensis

Cucurbit downy mildew caused by the oomycete pathogen Pseudoperonospora cubensis is a devastating disease that is distributed worldwide and affects cucumber in open fields and greenhouses. Fluopicolide, which was a novel systemic fungicide and was released in 2008, it is very effective in controlling downy mildew on cucumber and grape, potato late blight and pepper Phythophthora blight and reduces the loss caused by the diseases, but so far the potential for P. cubensis to develop resistance to fluopicolide has not been investigated. Hence, a laboratory study was undertaken to assess the risk of P. cubensis developing resistance to fluopicolide. Baseline sensitivity to fluopicolide was determined by using 75 P. cubensis isolates collected from cucumber-growing greenhouses in Hebei province, where no fluopicolide had been used for control of cucumber downy mildew before. Values of effective concentrations for 50% inhibition (EC₅₀) of sporulation ranged from 0.02 to 0.40 μg ml⁻¹ and were distributed as a unimodal curve, indicating that all 75 isolates were sensitive to fluopicolide. Sporangia of nine sensitive isolates were ultraviolet (UV)-irradiated, and four fluopicolide-resistant mutants were acquired at a mutation frequency of 7.4 × 10⁻⁷. Seven mutants resistant to fluopicolide were obtained from seven isolates by sporangia adaptation on fluopicolide-treated leaves of cucumber. The EC₅₀ values for all eleven fluopicolide-resistant mutants ranged from 3.37 to 13.06 μg ml⁻¹ with mean resistance factors of 7.9–118.0. After 10 sporangia transfers on fungicide-free leaves of cucumber, all eleven resistant mutants remained resistant to fluopicolide with mean resistance factors of 8.2–81.3. Seven resistant mutants from the selection for resistance and one resistant mutant from UV mutagenesis exhibited stable resistance; however, the other three resistant mutants from UV irradiation became significantly less resistant. Compared to their respective sensitive parents, the eleven resistant mutants exhibited diversity in latent period, infection frequency, lesion extension and sporulation ability. Five out of the eleven resistant mutants exhibited prolonged latent period and three out of the eleven resistant mutants provided decreased infection frequency (IF) compared to their respective parents, indicating that in some cases, resistance mutation might affect the latent period and IF of P. cubensis. There were significant differences in pathogenicity and ability to produce sporangia, but this seemed not to be caused by resistance mutation. No cross-resistance was detected between fluopicolide and azoxystrobin, metalaxyl, dimethomorph, or cymoxanil. In all, there could be a moderate to high risk of field populations of P. cubensis developing resistance to fluopicolide, and populations of P. cubensis should be monitored regularly for their shift of sensitivity over years of application.     

茶树种质叶片组织结构与其对黑刺粉虱抗虫性的关系

以田间虫口密度、网室内单位叶面积产卵量和世代存活率为指标测定了12份茶树种质对黑刺粉虱的抗虫性,并对叶片组织结构与网室内单位叶面积产卵量和世代存活率分别进行相关性分析。结果表明:优510、优3、丹桂、玉龙和九龙袍对黑刺粉虱的抗虫性较强,而G31、白鸡冠、福云10号和铁观音的抗虫性较弱。黑刺粉虱产卵量与气孔密度呈显著正相关(R=0.7950),与海绵组织厚度呈显著正相关(R=0.6790),而与栅栏组织厚度呈显著负相关(R=-0.7187,),与下表皮角质层厚度有接近显著水平的负相关(R=-0.6439);黑刺粉虱的世代存活率与气孔密度有接近显著的正相关(R=0.6654),而与下表皮厚度有极显著负相关(R=-0.8390),与下表皮角质层厚度有显著负相关(R=-0.7843),与栅栏组织厚度有极显著负相关(R=-0.8109)。