紫花苜蓿菌核病病原鉴定及其主要生物学特性

菌株NJ1分离自苏南丘陵地区苜蓿菌核病株.通过病原菌致病性测定和形态学特征观察,结合病原菌核糖体转录间隔区(ITS)序列分析,将病原菌鉴定为三叶草核盘菌(Sclerotinia trifoliorum).对该病原菌生物学特性研究表明,菌株NJ1菌丝生长最适温度为18～23℃;最适pH值为5～9;病原菌对硫酸铵利用能力强,对L-半胱氨酸利用能力差;对甘露醇和乳糖利用最好,D-果糖和D-木糖利用较差,不能利用柠檬酸.     

Sclerotinia rot resistance in red clover: Identification of RAPD markers using bulked segregant analysis

Random amplified polymorphic DNA (RAPD) was used with the objective of identifying DNA markers linked to the sclerotinia crown and stem rot (SCSR) resistance of red clover. Bulked segregant analysis was used to detect polymorphism that should be linked to SCSR resistance. Two bulks were made by pooling previously extracted DNA. Each bulk (one resistant, and the other susceptible) consisted of eight genotypes from an F₂ population obtained from a cross between a susceptible and a resistant parent. A binomial model was used to select RAPD fragments with a low probability of no linkage with SCSR resistance. Four RAPD fragments were retained as candidate markers of SCSR resistance. Three are associated with resistance and one with susceptibility.     

苜蓿菌核病生防菌及化学药剂的筛选

通过毒力测定法比较11种化学药剂对苜蓿菌核病的抑菌效果,其中45%五氯·福、50%速克灵和55%甲硫·菌核净可湿性粉剂3000倍液均能抑制病原菌生长。温室生测表明45%五氯·福防治苜蓿菌核病效果最好,500倍液防效达73.9%。从江苏省句容地区苜蓿根围土壤中分离到415株细菌,采用平皿对峙法从中筛选到3株对菌核病具有拮抗效果的生防菌,代号S1和S2的菌株抑菌效果最好,抑菌带超过1.5cm。温室生测菌株S2对苜蓿菌核病的生防效果最好,接种病原菌10d后防效达67.5%,15d后为61.7%。     

五种杀菌剂对紫云英菌核病大田防效测定

为筛选防治紫云英菌核病高效、低毒、低残留的杀菌剂,提高紫云英的鲜草产量,建立绿色安全的防控体系。[方法]通过调查紫云英菌核病在大田中的发病情况,试验五种杀菌剂在大田小区中的防治效果和防后紫云英鲜草产量对比。[结果]发现紫云英菌核病在大田中的发病十分严重,发病率达到88%,且多为严重发病；选用的五种药剂对紫云英菌核病发病率都有较好的抑制作用,效果最好的50%啶酰菌胺WDG防效为94.9%,效果最差的400g/L嘧霉胺SC防效为55.2%；紫云英盛花期药剂处理后的鲜草产量比空白对照增产11%～31%。[结论]该试验选用的五种杀菌剂中的50%啶酰菌胺WDG和50%腐霉利WP效果较好,为这两种药剂的安全使用和示范推广建立了基础。     

六种杀菌剂对制种生菜菌核病防治效果

经调查甘肃省酒泉市肃州区制种生菜菌核病在各生育期均有不同程度发病,为了筛选出能有效防治生菜菌核病的杀菌剂,本试验以发病较重的绿叶散叶型生菜为试验材料,选用6种杀菌剂对生菜菌核病病菌进行了抑菌作用研究。室内抑菌试验表明,50％福美双可湿性粉剂、70％菌核净可湿性粉剂、72.2％霜霉威盐酸盐水剂抑菌效果较显著,抑菌圈分别为32.7、 32、30.7 mm,而20％乙酸铜抑菌圈最小,为19 mm。5种药剂进行田间药效试验结果表明,70％菌核净可湿性粉剂1 000倍和50％福美双可湿性粉剂1 000倍的防效明显高于其他3种药剂,防效分别达到了77.71％和73.44％,是防治制种生菜菌核病的首选药剂。     

Intercropping winter cereals with Caucasian clover for forage in northern Europe

Intercropping cereal crops with perennial legumes for forage has been demonstrated as a means to improve nutritive value compared to cereal crops alone. Our objective was to determine whether sowing winter rye (Secale cereale L.) or winter triticale (x Triticosecale Wittmack) into living Caucasian clover (Trifolium ambiguum M. Bieb.) improves yield or nutritive value compared to monoculture cereal crop forage in northern Europe. The experiments were conducted near Moche?ek and Fal?cin, Poland. In autumn 2010 and 2011, winter rye was sown into existing Caucasian clover or in monoculture at Moche?ek, and winter triticale was sown into Caucasian clover or in monoculture at Fal?cin, with monoculture clover as a third crop treatment at both locations. The following spring, first harvest of forage from the three crop treatments was taken at two maturities: when monoculture cereals reached heading (BBCH 51) or grain milk stage (BBCH 71), and two additional harvests were taken from mixture plots and monoculture clover before autumn. First harvest forage yields of mixtures were similar to monoculture cereal at Fal?cin, less than monoculture cereal at Moche?ek, and greater than monoculture clover at both locations. Full season forage yields of mixtures were greater than both monoculture cereal and clover crops at both locations. The proportion of clover in mixtures was 20–31% in the first harvest, resulting in slightly lower neutral detergent fiber concentrations than in monoculture cereal crop at Fal?cin, but no improvement in nutritive value at Moche?ek. By spring 2012, most Caucasian clover had died from Sclerotinia trifoliorum infection at both locations, so forage was not harvested in the second year of the experiment. Although total season forage yields were greater for mixtures than for either monoculture cereal or Caucasian clover, this system cannot be recommended for northern Europe because of failure for Caucasian clover to persist.     

核盘菌和三叶草核盘菌的生态特性与致病性比较

在调查核盘菌和三叶草核盘菌发生为害的基础上，以核盘菌菌株Ｒａｐ－１和三叶草核盘菌菌株ＣＭＶ－２为代表，比较了温度及降雨等因子对菌丝生长及菌核萌发的影响。在１５￣２８℃下Ｒａｐ－１菌丝生长较ＣＭＶ－２快，但在８℃下则相反；Ｒａｐ－１菌核在自然条件下萌发期间的温度较ＣＭＶ－２菌核萌发时温度高，两者菌核萌发呈现出明显的先后秩序。春季降雨的波动导致２种核盘菌的菌核萌发出现波动。离体致病性测定结果表明，核盘     

Three Sclerotinia species as the cause of white mold on pea in Chongqing and Sichuan of China

White mold of pea caused by Sclerotinia sclerotiorum is a common disease in China. However, we discovered that the diverse Sclerotinia species could cause white mold on pea plants in Chongqing and Sichuan of China during recent disease surveys. Thus, the objective of this study was to confirm the causal agents from diseased pea plants. The obtained isolates of white mold from Chongqing and Sichuan were identified by morphological characters and molecular characterization to determine the pathogen species, and their pathogenicity was confirmed on pea through completing Koch's postulates. Fungal isolates of Sclerotinia-like were obtained from diseased plants or sclerotia. Based on morphological characteristics and molecular characterization, 30 isolates were identified to three species, six isolates as S. minor, seven as S. sclerotiorum, and 17 as S. trifoliorum. In pathogenicity tests on pea cultivars Zhongwan 4 and Longwan 1, all 30 isolates caused typical symptoms of white mold on the inoculated plants, and the inoculated pathogens were re-isolated from the diseased plants. This study confirmed that white mold of pea was caused by three Sclerotinia species, S. sclerotiorum, S. minor and S. trifoliorum in Chongqing and Sichuan. It is the first report that S. minor and S. trifoliorum cause white mold of pea in Southwest China.     

紫花苜蓿伴生菌对菌核病菌的抑制作用

为了从紫花苜蓿伴生菌中筛选生物防治菌种,采用对峙法和滤液培养法对紫花苜蓿伴生菌与菌核病菌的拮抗关系进行了研究,并采用茎秆接种法探讨了紫花苜蓿伴生菌对菌核病菌的控制作用。从紫花苜蓿植株中分离获得的22种真菌中,射丝孢、无孢菌丝体和丝葚霉对菌核病菌具有明显的拮抗作用;接种第5天,在含射丝孢、无孢菌丝体和丝葚霉3种真菌菌液的培养基上,三叶草核盘菌的菌落直径分别为4.8、26.8和28.9 mm,与对照相比,分别降低了75.2、53.2和51.1 mm。虽然射丝孢和无孢菌丝体都不能阻止菌核病菌侵入寄主组织,但对菌核病菌入侵后病斑的扩展表现出不同程度的抑制作用,其效果因品种而异,2种菌种对品种FGC901和Algonguin病斑扩展均表现出较好的抑制作用。     

Performance of Kura clover compared to that of perennial forage legumes traditionally cultivated in central Europe

Kura clover (Trifolium ambiguum M. Bieb.) is a rhizomatous perennial legume that is native to Caucasia, is extremely persistent in North America, but its performance has not been adequately evaluated in Europe. The objective of this research was to compare forage yield and nutritive value of Kura clover to lucerne (Medicago sativa L.), red clover (Trifolium pretense L.) and white clover (Trifolium repens L.) at two locations in Poland. All clover stands thinned markedly by spring of the second production year because of infection by Sclerotinia crown and stem rot, but lucerne stands remained dense and this legume produced the highest total yield over 3 or 4 production years. Kura clover yields of 7.2–8.3?Mg?ha^?1 were second to lucerne by the third production year but long-term performance was diminished by stand thinning. Kura clover and white clover had lower fiber concentrations and greater protein concentrations and forage digestibility than red clover and lucerne. Kura clover can be a source of high-quality forage in Europe, but cannot be recommended for use in areas with known Sclerotinia trifoliorum presence until resistance to this pathogen is developed.