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1.
枣棉间作条件下,通过设置两行枣树之间种植4行棉花(Int-4)与2行棉花(Int-2)两种不同的间作模式,研究一年生枣树对间作棉花的产量形成与影响因素。结果表明,不同间作模式棉花在盛花期前LAI、SPAD及光合生理特性差异不显著,盛花期后差异显著。与单作棉花相比,Int-4间作模式下棉花的株高、LAI及净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和产量比单作下降5.85%、10.40%、15.51%、13.26%、9.18%和41.61%,其胞间CO_2浓度(Ci)比单作增加4.18%;Int-2间作模式下棉花的株高、LAI及净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和产量比单作下降3.10%、5.39%、11.80%、9.25%、6.09%和47.74%,其胞间CO_2浓度(Ci)比单作增加0.84%;SPAD差异不显著。而经济收入表现为间作4行棉花模式间作2行棉花模式单作棉花,4行枣棉间作与2行枣棉间作相比,株高、LAI和干物质质量分别显著下降2.85%、5.29%和6.85%,Int-4产量比Int-2显著增加11.73%,而SPAD值和光合生理特性差异不显著。因此在枣棉间作系统中,适当增加棉花种植密度有利于棉花高产,同时有利于经济收入的增加。  相似文献   

2.
在杏棉间作条件下,研究了棉花不同田间配置对复合系统生态因子及棉花光合生理参数的影响.结果表明,各处理棉花冠层温度日均值变幅为24.49℃～35.19℃,并呈现出C＞B＞A的变化规律(A代表行数12行、株距12 cm、间距1.15 m的配置;B代表行数10行、株距10 cm、间距1.45m的配置;C代表行数8行、株距8 cm、间距1.85 m的配置),棉花冠层湿度则呈现出C＞A＞B的变化规律.在棉花见花期之前,20 cm处土壤温度一直以A处理最大,其次为B处理,见花期之后各处理间无差异.在棉花灌头水前,各处理20 cm处的土壤含水量差异明显,呈B＞A＞C的规律,40 cm处则差异不明显;灌头水之后,各处理40cm处土壤含水量差异显著,并呈现B＞C＞A的规律.全生育期各处理Pn呈现C＞B＞A的变化规律,与棉花冠层温度呈正相关,但与SPAD值不呈线性关系.皮棉产量以B处理最高,比A、C处理分别高4.69％、19.96％.在整个生育期,尽管果树遮阴影响,但杏棉复合系统内的温度条件都能满足棉花生长发育的需要,因此,棉花冠层湿度和土壤含水量的高低是影响棉花产量高低的重要因素.  相似文献   

3.
南疆杏麦复合类型对间作小麦产量及其构成因素的影响   总被引：11，自引：1，他引：10  
对南疆杏麦复合系统3种主要复合种植模式中距杏树不同距离小麦的产量及其构成因素进行了研究与分析。结果表明,在南疆杏麦复合系统中,杏麦间作类型对小麦产量影响很大,三种主要杏麦复合种植模式中,宽幅复合种植模式(6 m×3 m6、m×4 m)对小麦产量的影响远小于窄幅复合种植模式(4 m×1.5 m)的影响。间作小麦与杏树的距离愈近,对小麦产量影响愈大,南北走向的复合种植模式,对间作麦区东边的影响远大于西边。不同复合种植模式对小麦产量构成因素的影响中,4 m×1.5 m复合种植模式对小麦穗数和千粒重的影响较大,对穗粒数影响较小;而6 m×3 m6、m×4 m两种复合种植模式对穗数和穗粒数影响最大,对千粒重的影响较小。  相似文献   

4.
新疆枣棉间作下棉花光合特性及产量变化   总被引：2，自引：0，他引：2  
为了解枣棉间作模式中棉花的光合特性及产量,通过在棉花的苗期、现蕾期、花铃期、吐絮期利用Li-6400光合仪测量单作、间作下棉花的光合特性,分析比较单作、间作产量及经济产值。结果表明：单作、间作光合特性差异在花铃期最大,间作棉花在花铃期净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)比单作棉花分别低31.33%、15.13%、22.39%,而胞间CO2浓度(Ci)比单作棉花高8.90%;产量上间作棉花的收获株数、总成铃数、皮棉产量比单作棉花分别低28.26%、32.7%、41.61%;枣棉间作在土地利用率和总经济产值上具有明显优势,表现在枣棉间作模式提高了35%的土地利用率,比同面积单作棉花提高了41.27%的经济产值,比同面积单作枣树提高了30.63%的经济产值。枣棉间作下,间作对棉花光合的不利影响随着枣树和棉花的共进生长逐渐增大,间作造成棉花的减产,但是具有大幅提高土地利用率和经济效益的作用。  相似文献   

5.
SUNSCAN冠层分析系统在农田生态系统观测中的应用   总被引：11，自引：0，他引：11  
在夏玉米实验田对英国Delta公司生产的SUNSCAN冠层分析系统进行了实地验证,观察其对冠层上下PAR、LAI等生态指标的观测状况。结果表明:该系统可同步实现冠层顶部入射PAR、冠层底的TPAR、LAI及入射PAR中散射辐射占的比例等多项生态指标的测量,克服了以往仪器观测的繁琐及时间上的不同步性,其中对LAI的多样本无损伤性观测较传统方法更具有代表性;自动记录观测具有动态监测太阳总辐射的日变化功能,该系统最佳观测时段是上午9∶00～11∶00和下午13∶00～15∶00。SUNSCAN冠层分析系统是一种高效、轻便的测量工具,具有较大的应用潜力。  相似文献   

6.
以陇棉1号、陇棉2号、陇棉3号、酒棉11号、酒棉15号、酒棉17号、新陆早39、新陆早48、硕丰2号、耕野6号、金垦108号等11个适宜甘肃河西走廊棉区种植的棉花品种为材料,在大田条件下研究了全生育期4 800(I1)、3 600(I2)、2 400(I3)、1 200 m3·hm-2(I4)不同灌溉水平对棉花生长发育的影响,分析了在不同灌溉条件下的棉花产量及灌溉水生产力,并用抗旱性综合评价D值法及抗旱指数法对参试棉花品种(系)进行了抗旱性评价。结果表明:大部分棉花品种的株高、果枝数、单株铃数、铃重、绒长、单株干重及籽棉产量在轻度的水分胁迫下增加,但在重度的水分胁迫下显著降低;所有棉花品种在I3灌溉水平下其灌溉水生产力最高,硕丰2号、新陆早48、酒棉11号、陇棉1号、陇棉3号、陇棉2号的最佳灌溉条件为I3,其产量与灌溉水生产力均达到最高,酒棉15号、新陆早39最佳灌溉条件为I2,耕野6号、金垦108号、酒棉17号在充足灌水条件下籽棉产量最高,但灌溉水生产力低;酒棉17号、陇棉3号为高抗旱品种,硕丰2号、耕野6号为中抗旱品种,新陆早48、陇棉1号、陇棉2号、金垦108号为弱抗旱品种,新陆早39、酒棉11、酒棉15号对干旱较为敏感。  相似文献   

7.
不同间作种植模式对棉花生长发育及品质影响   总被引：1，自引：0，他引：1  
本研究旨在通过大田试验,分析塔里木地区不同枣棉间作间距对花铃期棉花生长发育以及品质的影响,为优化枣棉间作种植模式提供理论依据。结果表明:1棉花与红枣行间距主要影响棉花盛铃-吐絮进程。M1模式(距离红枣1.5 m处种植棉花)棉花生育期最短,为143 d;M3模式(距离红枣0.5 m处种植棉花)最长,为149d。2花铃期,M2模式(距离红枣1.0 m处种植棉花)株高、茎粗、成铃数均优于其他模式。3M1模式棉花叶片、茎秆干物质积累显著高于其他模式。4M1模式棉花产量为2 436.79 kg·hm-2,显著低于其他处理,但是衣分率(0.447)、霜前花率(83.24%)显著高于其他处理;M2模式籽棉产量为4 071.87 kg·hm-2,显著高于其他处理。5随棉花与红枣行间距的减小(M1→M3),棉纤维反射率小幅上升,断裂比强度、马克隆值呈降低趋势。结合生产实际,阿拉尔垦区幼龄枣园中棉花与红枣保持1.0 m距离,能够产生较高的经济效益。  相似文献   

8.
玉米不同密度下间作大豆控草效果及对产量的影响   总被引：2，自引：0，他引：2  
以贵州主要种植的玉米品种黔单16和大豆品种黔豆2号为材料,开展不同密度下玉米间作大豆控草效果及对产量的影响研究。研究结果表明:玉米种植密度在4.2万~5.55万株/hm~2按1∶1间作大豆对杂草的株抑制率为37.43%~50.30%,鲜质量抑制率47.79%~52.96%,在该密度范围内,抑制效果随着玉米种植密度的增加而增加。玉米单作下田间杂草冠层平均光合有效辐射(PAR)为330.07~698.13μmol/(m~2·s);间作模式田间杂草冠层平均光合有效辐射(PAR)为73.27~108.33μmol/(m~2·s);随着玉米种植密度的增加,各种植模式田间光合有效辐射(PAR)逐渐降低,间作模式光合有效辐射(PAR)普遍高于玉米单作模式,这可能是抑制田间杂草生长的主要原因。在产量上,玉米单作产量随种植密度增加而增加;玉米-大豆间作模式下玉米产量相对稳定,大豆产量随玉米密度增加而增加。在玉米种植高密度下玉米单作产量高于间作模式,但间作模式经济效益高于玉米单作种植模式,以玉米-大豆5.55万株/hm~2密度下田间作物产量经济效益最高。因此,作物合理间作和适当增加种植密度是控制杂草生长,提高作物产量的有效措施。  相似文献   

9.
为探明农果间作水分高效利用机理,提出适合南疆地区最优的农果间作模式,在大田试验条件下对枣棉间作系统进行研究,以种植模式（枣棉间作和枣、棉单作）和田间配置（棉花种植行数分别为2、4、6行;棉花株距分别为10 cm和12.5 cm）为参试因子,共9个处理,田间随机排列,共27个小区,小区面积为3 m×10 m。测定了各处理的耗水特征、产量、水分利用效率（WUE）和水分当量比（WER）等指标。结果表明：种植模式显著影响复合群体的耗水特性,枣棉间作耗水量较单作加权平均增加9.5%,棵间蒸发量降低11.4 mm,蒸散比降低13.5%。棉花种植行数显著影响复合群体的耗水特性,间作6行棉花较间作2行棉花耗水量增加9.1%~13.9%;间作6行棉花分别较间作4行和2行棉花提高土壤贮水消耗量35.2 mm和66.3 mm,棵间蒸发量分别降低24.2 mm和33.7 mm,蒸散比分别降低16.0%和22.2%;棉花株距变化仅对土壤贮水消耗量有显著影响,I3处理（间作棉花4行）土壤贮水消耗量较I4（间作棉花2行）高24.4 mm,I1（株距10 cm）较I2(株距12.5 cm)高14.7 mm。枣棉间作群体对40~60 cm土层土壤贮水消耗量最高,20~40 cm土层次之,80~100 cm土层最低;单作枣树对土壤深层水分利用较多,单作棉花则主要消耗浅层土壤中的水分,枣棉间作能够较好地利用土壤各层的水分。就土壤贮水利用而言,增加棉花行数或减小株距有助于促进40~80 cm土层土壤贮水的利用。不同枣棉间作处理的WER都大于1,说明枣棉间作较单作提高了农田WUE。间作棉花种植行数为4行、株距为12.5 cm时,枣棉间作综合效益最优,产量为7 460 kg·hm-2,WUE为11.37 kg·mm-1·hm-2,WER为1.34。  相似文献   

10.
以新陆早7号为试材，进行了不同水肥条件下膜下滴灌棉株群体冠层结构测定和产量结果分析。试验表明，合理水肥条件下的棉株群体叶面积指数(LAI)、叶倾角(MLA)和散射光透过率(TD)，在盛花盛铃期分别为3.55～3.95、40°～48°和18.5%～28.1%。在一定水肥范围内，滴灌棉花产量随灌水量和施肥量的增加而增加，但超过一定阈值产量有下降趋势。适宜水肥条件下产量最高。  相似文献   

11.
Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.  相似文献   

12.
Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.  相似文献   

13.
Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.  相似文献   

14.
A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVYN strain and six to the PVYO strain. No PVYC was found. Two other isolates reacted serologically like PVYO, but were unable to elicit a hypersensitive response from the Nytbr gene and probably represent the PVYZ group. At the molecular level, these two isolates showed a combination of both PVYO and PVYN and could be recombinants of these strains. Another isolate reacted serologically like PVYO, but induced vein necrosis in tobacco, like PVYN-Wilga. Some PVYN isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVYNTN group. The PVYNTN, PVYN-Wilga and PVYZ groups probably represent pathotypes within strains PVYN and PVYO, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.  相似文献   

15.
The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed.  相似文献   

16.
In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population.  相似文献   

17.
Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.  相似文献   

18.
Zusammenfassung Herbizidresistente Kulturpflanzen nehmen unter den derzeit weltweit angebauten gentechnisch veränderten Ackerbaukulturen Sojabohne, Baumwolle, Raps und Mais den weit überwiegenden Anteil ein. Als Ursachen für die rasche Zunahme der Anbauflächen herbizidresistenter Sorten sind unter anderem die Unzulänglichkeiten der für diese Kulturen bestehenden Herbizidlösungen sowie die Zunahme der pfluglosen Bestellverfahren zu sehen. Im Gegenzug hat die Minimalbodenbearbeitung aufgrund der Einführung der Herbizidresistenztechnologie, insbesondere in Sojabohne, ein ausgeprägtes Flächenwachstum erfahren.Als Entscheidungskriterien für die Wahl des Unkrautbekämpfungssystems unter Einbezug des Anbaus herbizidresistenter oder konventioneller Sorten lassen sich aus den Erfahrungen der vergangenen 8 Jahre anführen: Sortenleistung, erhöhte Kulturverträglichkeit und zeitliche Anwendungsflexibilität, Wirkungssicherheit einer Nachauflaufbehandlung in Trockenregionen, Wirkungsbreite, Wirkungsdauer und Bekämpfung resistenter Unkrautbiotypen. Aufgrund fehlender Zulassungen und Kennzeichnungsvorschriften in wichtigen Exportmärkten sind für den Anbau transgener Sorten in Übersee auch Vermarktungseinschränkungen sowie für den Anbau in Europa Haftungs- und Koexistenzregeln wichtige einzelbetriebliche Entscheidungsparameter.Fortschritte erfährt die Herbizidresistenztechnologie kurz- und mittelfristig in der Weiterentwicklung bereits praktizierter Spritzfolgen und Tankmischungen zu Fertigformulierungen der Komplementärherbizide mit residualen Partnern. Zur Bekämpfung und Vorbeugung der Ausbreitung neuer herbizidresistenter Biotypen werden die Komplementärherbizide mit Partnern anderer Wirkungsmechanismen kombiniert. Weitere Entwicklungen sind die Kombination verschiedener transgener Merkmale mit der Herbizidresistenz sowie die Ausweitung von den derzeit dominierenden Kulturen auf weltweit weniger bedeutsame Kulturen, in denen die Entwicklung neuer konventioneller Herbizidwirkstoffe bisher wenig erfolgreich war oder im Verhältnis zum Aufwand nur bedingt attraktiv ist. Für die langfristige Entwicklung könnte die Plastidentransformation zur Verhinderung einer unerwünschten Ausbreitung transgener Merkmale Bedeutung erlangen.  相似文献   

19.
Research on root rot pathogens of peas in the Netherlands has confirmed the prevalence ofFusarium solani, F. oxysporum, Pythium spp.,Mycosphaerella pinodes andPhoma medicaginis var.pinodella. Aphanomyces euteiches andThielaviopsis basicola were identified for the first time as pea pathogens in the Netherlands. Other pathogens such asRhizoctonia solani andCylindrocarpon destructans were also found on diseased parts of roots. F. solani existed in different degrees of pathogenicity, and was sometimes highly specific to pea, dwarf bean of field bean, depending on the cropping history of the field.A. euteiches was specific to peas, whereasT. basicola showed some degree of physiological specialization.  相似文献   

20.
Data from surveys of winter wheat fields in the period 1974–1986 and of seed lots in the period 1962–1986 and identifications of diseases on plant samples were compiled to describe the occurrence of snow mould (Monographella nivalis) andFusarium spp. On average,M. nivalis dominated overFusarium spp. The complex ofFusarium spp. constituted mainly ofF. culmorum, followed byF. avenaceum andF. graminearum. M. nivalis was dominant in May on stem-bases and in July on leaves and leaf sheaths. On seedsM. nivalis predominated only in years with low temperatures in July and August.Average brown footrot infection in the field was 4% tillers in May and 5% culms in July. Brown footrot intensity in July was high in cropping seasons with high precipitation in October and with low temperatures in October, November and December. In July during the early eighties, an average of 8% of leaves and 6% of flag leaf sheaths were infected byM. nivalis. Average ear blight incidence was 1.2% glumes infected. Seed contamination by these pathogens averaged 16% in the years 1962–1986. The contamination was high in years with high precipitation in June, July and August. Aspects of cv. resistance and yield loss are illustrated.  相似文献   

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