大豆灰斑病抗性遗传的三点测交分析

本实验利用三点测交分析的方法, 对3个组合在人工接种大豆灰斑病菌的条件下的抗性表现进行基因效应分析,各组合均存在加性,组合1存在显性,组合2、3存在上位性。 Abstract:In this paper,Triple Test Cross Design was used in studing the resistance of soybean to 10 physiological race of Cercospora Sojina Haraby inoculation.Results o analysis of gene effects of resistance indicated that additive effect is significant in all the three crosses,dominant effect exsists only in the cross 1 and epistatic effect remains in the cross 2 and cross 3.     

Production and Characterization of a Pressure-induced Gel from Freeze-concentrated Milk

A process was developed to produce a characteristic milk gel. Raw and market milk samples were freeze-concentrated using bacterial ice nuclei. The concentrates were kept at 5°C and compressed at 300–600 MPa for 5 min. The combination of the freeze concentration and the pressurization gave a milk gel without adding any gelling agents. The addition of sugar at 10% to the concentrated milk improved its gel strength and viscoelasticity. The gel was characterized by a phase transition at about 62–75°C.     

Evaluation of the potential for sexual reproduction in field populations of Cercospora beticola from USA

Cercospora leaf spot, caused by the hemibiotrophic fungal pathogen Cercospora beticola, is the most economically damaging foliar disease of sugarbeet worldwide. Although most C. beticola populations display characteristics reminiscent of sexual recombination, no teleomorph has been described. To assess whether populations in northern United States have characteristics consistent with sexual reproduction, 1024 isolates collected over a 3-y period were analyzed for frequency and distribution of mating type genes. After clone correction, an approximately equal distribution of mating types was found for each sampling year. Mating type frequency was also assessed in individual lesions. Lesions always consisted of isolates with a single mating type and microsatellite haplotype, but both mating types and up to five microsatellite haplotypes could be found on an individual leaf. The MAT1-1-1 and MAT1-2-1 genes were sequenced from 28 MAT1-1 and 28 MAT1-2 isolates, respectively. Three MAT1-1-1 nucleotide haplotypes were identified that encoded a single amino acid sequence. For MAT1-2-1, five nucleotide haplotypes were identified that encoded four protein variants. MAT1-1-1 and MAT1-2-1 gene expression analyses were conducted on plants inoculated with either or both mating types. MAT1-1-1 expression remained low, but MAT1-2-1 spiked during late stages of colonization. A segment of the MAT1-2-1 coding sequence was also found in MAT1-1 isolates. Taken together, these results suggest that C. beticola has the potential for sexual reproduction.     

Effectiveness of acibenzolar-S-methyl, fungicides and antibiotics for the control of brown eye spot, bacterial blight, brown leaf spot and coffee rust in coffee

This study was carried out to evaluate the potential of acibenzolar‐S‐methyl (ASM), combined or not combined with fungicides and antibiotics for the control of brown eye spot (Cercospora coffeicola) and bacterial blight (Pseudomonas syringae pv. garcae) in coffee seedlings, and ASM combined with conventional fungicide application schedules for the control of coffee rust (Hemileia vastatrix) and brown leaf spot (Phoma costarricencis) under field conditions in two coffee crops in the State of São Paulo, Brazil. ASM protected coffee seedlings against C. coffeicola when applied at the rates of 2.5 and 5 g of active ingredient per hectolitre of water (g a.i. hL^?1), providing 34–55% of disease control, and against bacterial blight, when applied at the rates of 2.5, 10 and 20 g a.i. hL^?1, with 38–57% of disease control. Tebuconazole (100 g a.i. hL^?1) and azoxystrobin (10 g a.i. hL^?1) showed the best results for brown eye spot control. Oxytetracycline + streptomycin, kasugamycin hydrochloride, oxytetracycline + metallic copper, copper oxychloride and mancozeb + copper oxychloride also controlled bacterial blight in levels similar to those shown by ASM. In the field experiments, all fungicide application schedules tested, cyproconazole (December, February, April), epoxiconazole (December, March), tetraconazole (December, February, April), cyproconazole (December, February) and azoxystrobin (January, March) were effective for coffee rust control and provided partial control of brown leaf spot. The results also showed that for all experiments, there was no synergistic effect of the combination of ASM with azoxystrobin, cyproconazole or cupric fungicides.     

Effect of Cercospora zeae-maydis infested maize residue on progress and spread of grey leaf spot of maize in central Uganda

The spread of grey leaf spot caused by Cercospora zeae‐maydis from infested maize residue on the soil surface and progress over time were studied under tropical conditions at two locations in central Uganda, Kabanyolo and Namulonge, using a susceptible local cultivar, LP16. Infested maize residue collected the previous season was used as the inoculum source in varying amounts; 80% coverage, 40% coverage and 0% soil coverage were used to simulate no tillage, minimum tillage and maximum tillage with complete burial of residues. In all the seasons, disease spread was adequately described by a power law model, whereas disease progress over time was equally well represented by both Gompertz and logistic models. The time factor was highly significant (P < 0.05) for disease development, indicating both increases in disease intensity over time and change in gradients with time. The amount of infested residue on the soil surface in the maize planting was highly significant (P < 0.05) for slope (b) and intercept (a) of the linearised disease gradient. The gradient parameter (b) based on the average for the four directions from the residue source ranged from ?0.96 to ?0.08 in the second cropping season of 1999, from ?2.16 to ?0.01 and from ?0.87 to ?0.03 in the first and second seasons of 2000, respectively. The distance from the infested residue significantly affected foliar disease, but the direction from the residue inoculum source did not, nor was the distance by direction interaction significant. However, interactions between amount of residue and distance were significant. Percentage leaf area affected by grey leaf spot, the areas under disease progress curves and disease intercepts decreased with distance at both locations, but rate of disease increase (r) was generally constant with distance from residue source at Kabanyolo, but not at Namulonge. The relationship between disease severity and amount of residue cover appeared to be affected by the level of background inoculum. At Kabanyolo, where little background inoculum was present, differences were detected in disease severity parameters between the no‐residue plots and residue plots, whereas at Namulonge, where high background levels existed, there was no effect of residue on disease.     

Addition and re-examination of Japanese species belonging to the genus <Emphasis Type="Italic">Cercospora </Emphasis>and allied genera. V. Collections from the Nansei Islands (2)

 Five species collected in the Nansei Islands are discussed. Of these, one species found on Gardenia jasminoides is described as a new species, Cercosporidium okinawaense Kobayashi et Nishijima. Asperisporium caricae on Carica papaya, Pseudocercospora melastomobia on Melastoma candidum, and P. neoliquidambaris Nakashima et Kobayashi, nom. nov. on Liquidambar formosana are newly added to the Japanese mycoflora. Cercospora violamaculans on Rhaphiolepis umbellata is transferred to the genus Pseudocercospora as Pseudocercospora violamaculans (Fukui) Kobayashi et Nakashima, comb. nov., with some additional notes. Received: October 26, 2001 / Accepted: March 13, 2002     

中国尾孢菌属及其近似属的研究VI.(英文)

本文报道９种尾孢菌,其中有２个新种：蟹甲草尾孢 Ｃｅｒｃｏｓｐｏｒａ ｃａｃａｌｉａｅ Ｙ． Ｌ． Ｇｕｏ　＆ Ｙ．Ｊｉａｎｇ和菜蓟尾孢Ｃｅｒｃｏｓｐｏｒａ 　ｃｙｎａｒａｅ Ｙ． Ｌ． Ｇｕｏ　＆ Ｙ． Ｊｉａｎｇ,中国新记录种有迪氏尾孢Ｃｅｒｃｏｓｐｏｒａｄｅｍｅｔｒｉｏｎｉａｎａ　 Ｇ． Ｗｉｎｔｅｒ,田菁生尾孢 Ｃｅｒｃｏｓｐｏｒａ　 ｇｌｏｔｈｉｄｉｉｃｏｌａ 　Ｔｒａｃｙ　＆ 　Ｅａｒｌｅ,甘草尾孢 Ｃｅｒｃｏｓｐｏｒａｇｌｙｃｙｒｒｈｉｚａｅ 　（Ｓａｖｕｌｅｓｃｕ　＆　Ｓａｎｄｕ）Ｃｈｕｐｐ,野桐尾孢Ｃｅｒｃｏｓｐｏｒａ　ｍａｌｌｏｔｉ　Ｅｌｌｉｓ　＆ 　Ｅｖｓｒｈ,木薯尾孢Ｃｅｒｃｏｓｐｏｒａ ｍａｎｉｈｏｂａｅ Ｖｉｅｇａｓ,补骨脂尾孢 Ｃｅｒｃｏｓｐｏｒａ ｐｓｏｒａｌｅａｅ－ｂｉｔｕｍｉｎｏｓａｅ Ｓａｖｕｌ．＆ Ｓａｎｄｕ和香豆尾孢Ｃｅｒｃｏｓｐｏｒａ ｔｒａｖｅｒｓｉａｎａ Ｓａｃｃ。文中为新种提供了拉丁文描述并附图,研究的标本保存在中国科学院微生物研究所菌物标本馆（ＨＭＡＳ）。     

中国尾孢菌属及其近似属的研究VIII.

报道钉孢属一个新种生在梾木属Cornussp.上的梾木钉孢Passaloracorni和1个新组合生在四叶重楼Parisquadrifolia.上的重楼钉孢Passaloraparidis;尚有尾孢菌属的4个中国新记录种南蛇藤生尾孢Cercosporacelastricola.,危地马拉尾孢Cercosporaguatemalensis,大薸尾孢Cercosporapistiae,和鼠尾草生尾孢Cercosporasalviicola。为新种提供了拉丁文简介、英文描述并绘图。标本保存在中国科学院微生物研究所菌物标本馆(HMAS)。     

Aerobiology in plant protection

Summary The control of phytopathogenic fungi in agriculture requires sometimes excessive chemical treatments because, in many cases, reliable monitoring systems in order to assess the real risk for the cultivations are not available.Therefore, the likelihood to assess the presence and the amount of phytophatogenic fungus propagules in the air with a spore-trap has been investigated in order to evaluate their correlation with the climate and the disease occurrence. Four phytopathogenic fungi, namelyVenturia inequalis, Phytophthora infestans, Cercospora beticola andDiaporthe phaseolorum var.caulivora were taken into consideration.Practical use of airborne spore monitoring in a disease control strategy proved to be useful only forVenturia inequalis andPhytophthora infestans causal agent of apple scab and tomato late blight respectively. For the latter, the utilisation of an aerobiological monitoring system for the disease prediction can be assumed.     

尾孢菌属一新种

本文报道寄生在鳞毛颜料（DryoPteridaceae）卵果蕨（DryopterispolypodioidesFee）上的尾孢菌属一新种——鳞毛藏尾孢（CercosporadryopteridisY.L.Guo,sp.nov.）。尾孢菌属真菌在鳞毛蕨科是首次报道。鳞毛蕨尾孢叶斑角状至不规则形,灰白色至浅黄褐色。子实体主要生在叶背面。分生孢子梗单生或2～12根簇生,青黄褐色至中度褐色,顶部色泽较浅,宽度不规则,常基部较宽,不分枝或偶具分枝,1～4个屈膝状折点,1～5个隔膜,40～150（～210）×4．3～6μm。孢痕疤明显加厚,宽2．5～3.2μm。分生孢子无色,针形,直立或弯曲,顶端尖细,基部平截,具不明显的多个隔膜,95～250×3.7～4.8μm。文中为新种提供了拉丁文简介并附图。模式标本保藏在中国科学院微生物研究所真菌标本室（HMAS）。