Development of Stem-base Pathogens on Different Cultivars of Winter Wheat Determined by Quantitative PCR

The progress of development of stem-base pathogens in crops of second winter wheat was plotted in nine experiments in three years. The amount of each pathogen present was determined by quantitative PCR. Where Tapesia yallundae was present in quantifiable amounts, it usually developed earlier than the other eyespot pathogen, T. acuformis. Both species were usually present in greater amounts on cultivars which are more susceptible to eyespot. The sharp eyespot pathogen, Rhizoctonia cerealis, developed more erratically than either of the Tapesia spp. and there were no consistent effects on different cultivars. Fusarium spp., the cause of brown foot rot, were rarely present in quantifiable amounts, but Microdochium nivale was usually present as one or both of the varieties nivale and majus. Late-season (after anthesis) decreases in M. nivale suggest that any brown foot rot symptoms attributable to this fungus would have fully developed earlier. Cultivar differences in amounts of M. nivale were most clear in stems during internode extension and when relatively large amounts of DNA were present. Such differences approximately reflected eyespot susceptibility, cv. Soissons containing most and cv. Lynx containing least DNA. The results emphasise the difficulty in relating diagnoses, by quantitative PCR or other means, at early growth stages when decisions to apply fungicides against stem-base disease are made, to later disease severity.     

小麦品种纹枯病抗性鉴定

小麦纹枯病是由禾谷丝核菌 (Ｒｈｉｚｏｃｔｏｎｉａｃｅｒｅ ａｌｉｓ)侵染所致的土传病害[1 ] 。近年来 ,该病害在湖北省麦区发生日趋严重[2 ,3] ,已逐渐成为生产上的一种重要病害。培育抗纹枯病品种和鉴定筛选抗源并在育种工作中加以利用是控制该病害的重要途径。本研究对湖北省麦区近年来推广的 2 5个品种以及从全国各地征搜集的 548份材料进行了鉴定和筛选 ,以期明确湖北省麦区品种的抗性现状 ,为育种单位提供抗源和小麦品种合理布局提供科学依据。1　材料与方法1 .1　材　料供试小麦品种为湖北省近年来推广品种 2 5个和从全国各地征搜…     

大豆纹枯病与其种植密度的关系

通过对大豆不同密度条件下大豆纹枯病的发生级别及普遍率的关系研究 ,发现大豆纹枯病的发生级别与普遍率都随着大豆密度的增加而增加 ,并提出防治大豆纹枯病的方法     

Effect of Drechslera (Helminthosporium) sacchari Toxin upon the Permeability of Sugarcane Leaf and Callus Tissues

Sugarcane leaves and calli from highly susceptible and resistant varieties to eyespot disease were used to evaluate the Drechslera sacchari toxin effect at different concentrations and incubation times by measuring electrolyte leakage. This expression of disease resistance was observed not only in the leaf but also in the callus. Furthermore, the growth of resistant calli MS medium supplemented with DS toxin, was higher when compared to the susceptible ones. The possibility of obtaining resistant somaclones is confirmed.     

小麦纹枯病抗性QTL的SSR标记研究

以ARz／扬麦158F6重组自交系(RILs)群体为材料,对其纹枯病抗性进行SSR分析和初步的QTL分析。群体抗性分析结果表明：纹枯病抗性是由多个基因控制的数量性状;单个标记方差及回归分析显示有6个SSR标记至少在2份抗性资料中能被检测到,涉及2D、3A、3B、3D、7D5条染色体,能解释2．6％～10．1％的抗性表型变异。标记Xgwm340来源于感病品种扬麦158,其余的SSR标记(Xgwm102、Xgwm155、Xgwm71—2、Xgwm645、Xgwm437)来源于抗病亲本ARz;利用Map Manager QTX软件进行QTL分析,检测到2个QTL。     

An Epidemiological Study on Orodental Disorders in 3,791 Working Donkeys in Egypt: Prevalence and Risk Factors

Orodental disorders are common in equidae and can lead to serious clinical complications. This study determines the prevalence rate (PR) of orodental disorders in working donkeys in Egypt and their potential risk factors. During 4 years, 3,791 donkeys were examined in six Egyptian governorates. Full case history and thorough clinical and oral examinations were performed. Radiography and oroendoscopy were undertaken whenever possible. All data were statistically analyzed using Poisson generalized linear models to compare PR among governorates, sex, years, body condition score, and age groups and to determine the potential risk factors. Of 3,791 examined donkeys, 954 donkeys (25.17%) had orodental disorders. The PRs of acquired disorders were 9.81% sharp enamel points, 5.86% buccal ulcers, 4.88% hook, 4.70% overgrown teeth, 4.19% periodontal disease, 3.11% ramp, 2.60% dental caries, 2.37% dental calculus, 2.30% diastema, 2.06% step mouth, 2.00% soft tissue injuries other than buccal ulcers, 1.77% worn tooth, 1.37% loose tooth, 1.29% exaggerated transverse ridge, 1.24% fractured teeth, 0.82% missing teeth, 0.69% wave mouth, 0.50% molar table angle change, and 0.45% wolf tooth overgrowth. The PRs of the congenital disorders were 1.90% displaced teeth, 1.37% deviated teeth, 0.58% retained teeth, 0.16% overbite, 0.16% underbite, 0.11% supernumerary teeth, and 0.11% premolar cap. The risk factors significantly associated (P < .05) with the orodental disorders were age and sex of the animal, geographic location, and year of examination. This study provides a database for future studies on orodental disorders and for designing effective preventive and therapeutic strategies for these disorders in donkeys.     

小麦纹枯病和白粉病双抗抗源的初步鉴定

“七五”和“八五”期间,进行了大量的小麦常规品种(系)之间,以及与近缘物种的杂交工作,从某些杂种后代中,筛选出几百份抗白粉病优良选系。为了创造兼抗纹枯病和白粉病的双抗抗源,于1997 年春整理部分优良选系、地方品种和国外引进品种(系),共182 份小麦材料进行的纹枯病抗性和白粉病抗性鉴定,对部分抗性材料于当年秋在温室接种情况下继续进行抗性鉴定。初步鉴定结果表明:有27 份材料与对照材料相比纹枯病病情指数较低,显示了较强的抗(耐)纹枯病能力;其中有16 份材料表现出兼抗纹枯病和白粉病。另外,对部分小麦的近缘物种的初步鉴定发现球茎大麦、多花黑麦草和黑麦等对白粉病和纹枯病有很强的抗性。     

45%烯肟菌胺·苯醚甲环唑·噻虫嗪悬浮种衣剂对小麦纹枯病和蚜虫的防治效果

为了解45%烯肟菌胺·苯醚甲环唑·噻虫嗪FSC对小麦纹枯病、蚜虫的防治效果及推广用量,室内试验以辽春10号为材料,研究了45%烯肟菌胺·苯醚甲环唑·噻虫嗪FSC对小麦生长发育的影响及对纹枯病的防效;田间试验以济麦22和中麦895为试验材料,探索了45%烯肟菌胺·苯醚甲环唑·噻虫嗪FSC防治小麦纹枯病、蚜虫的推广剂量。结果发现,133~800g·100kg-1种子的45%烯肟菌胺·苯醚甲环唑·噻虫嗪FSC对辽春10号发芽率、株高、根长及鲜重无明显影响;400~800g·100kg-1种子45%烯肟菌胺·苯醚甲环唑·噻虫嗪FSC对辽春10号小麦纹枯病有较好防效。400~800g·100kg-1种子45%烯肟菌胺·苯醚甲环唑·噻虫嗪FSC对中麦869纹枯病防效为66.4%~86.7%,明显高于对照药剂;对扬花末期蚜虫防效为95.8~97.3%,防效与对照药剂无明显差异;对济麦22纹枯病防效为55.8~62.7%,与对照药剂无明显差异;对扬花末期蚜虫防效为80.2~90.1%,与对照药剂无明显差异。45%烯肟菌胺·苯醚甲环唑·噻虫嗪悬浮种衣剂对小麦蚜虫和纹枯病具有良好防治效果,推荐剂量为400~800g·100kg-1种子。     

pseP基因对蜡样芽胞杆菌0-9菌株生物薄膜形成和防治小麦纹枯病的影响

为了阐明芽胞杆菌0-9菌株的生防机制,通过敲除0-9菌株的多糖外运蛋白编码基因pseP构建基因敲除菌株0-9（ΔpseP）和基因敲除菌株的互补菌株0-9（ΔpseP∷pseP）,并比较野生型0-9菌株及其衍生菌株形成生物薄膜的能力及其对小麦纹枯病的生防效果。结果显示,pseP基因敲除后,菌株生物薄膜形成能力和对小麦纹枯病的生防作用降低,生防效果较野生型0-9菌株降低43.6%。基因互补后,互补菌株生物薄膜的形成能力和对小麦纹枯病的生防作用得到恢复,生防效果较敲除菌株提高29.2%。研究表明蜡样芽胞杆菌0-9菌株的pseP基因参与了生防菌株0-9生物薄膜的形成和对小麦纹枯病的生物防治。