Inconspicuous restraint of rice seedling growth by root-infecting fungi in soil of a rice paddy field     

Hiromitsu Furuya  Tsutomu Matsumoto  Shin-ichi Fuji  Hideki Naito 《Journal of General Plant Pathology》2003,69(2):115-119

 Rice seedling growth, estimated by plant height and root development and discoloration, was better in pasteurized soil than in unpasteurized soil obtained from a flooded rice field. Rice seedlings also grew better in sterilized soil modified by adding roots harvested from the pasteurized soil than in soil modified by adding roots harvested from the unpasteurized soil. The results demonstrate that seedling growth in the rice field soil was inhibited by soil microorganisms, even though no typical symptoms such as seedling blight or damping-off appeared. Pythium aristosporum is suggested to be involved in the inhibition. Thus, it appears that inconspicuous restraint of rice seedling growth could occur in soils of rice paddy fields. Received: May 20, 2002 / Accepted: October 16, 2002 Acknowledgments The authors thank Dr. T. Ichitani, former professor at Osaka Prefectural University, for providing an isolate of Pythium aristosporum for comparison, and Mr. Mitsuaki Sato of Akita Prefectural College of Agriculture for technical assistance.  相似文献   

亚洲玉米螟大量饲养中微孢子虫病控制技术   总被引：2，自引：0，他引：2       下载免费PDF全文

文丽萍  王振营  何康来  白树雄  周大荣 《植物保护学报》2003,30(1):13-18

利用与人工饲料相混合的方法，比较了不同剂量的烟曲霉素B对亚洲玉米螟微孢子虫病的控制效果。结果表明，烟曲霉素B453、565和683μg/g的剂量处理都显著降低了亚洲玉米螟微孢子虫病的感染率和感染强度。食药1代时，幼虫和成虫感染率分别比对照平均减少44．4％—61．1％和41．7％—50％，其感染强度都由原来的严重感染分别下降为轻度感染。幼虫存活率、化蛹率、成虫繁殖力也均显著高于对照。连续处理3代饲喂烟曲霉素B对玉米螟生长发育没有不利影响，对微孢子虫病的控制作用随处理世代数的增加亦有增加的趋势。不同剂量的烟曲霉素B处理间的防效差异不显著，453μg/g可作为亚洲玉米螟大量饲养中控制微孢子虫病的推荐剂量。  相似文献   

大白菜细胞核雄性不育基因向自交系97A407的转育   总被引：9，自引：0，他引：9  

许明  白明义  魏毓棠 《中国蔬菜》2003,1(2):8-10

根据复等位基因遗传假说 ,利用大白菜核不育系 9810 9和已知基因型的甲型两用系可育株 99135 2作为不育源 ,以大白菜自交系 97A40 7为目标亲本 ,经过 5个世代的转育 ,获得了具有 97A40 7遗传基因型的新甲型两用系、临时保持系和雄性不育系。  相似文献   

小麦印度腥黑穗病菌在中国适生性的初步研究   总被引：9，自引：2，他引：9  

白章红  周国梁 《植物检疫》1997,11(6):331-334

本文依据小麦印度腥黑穗病菌的生物学特性，及世界各主要小麦产区的地理气候资料，利用地理信息系统对该病菌的适生性进行了研究。结果表明，小麦印度腥黑穗病菌适生气候条件为：大于零度以上的有效积温≥１３００日度；１年中最冷月的平均温度≤２０℃；小麦抽穗扬花期间的平均温度为７℃～２９℃，平均大气相对湿度≥４８％。  相似文献   

京郊保护地秋季番茄的氮素供应及利用   总被引：4，自引：0，他引：4  

白优爱  贺建德  陈清  李晓林 《中国蔬菜》2004,1(2):7-9

研究了氮素供应水平对保护地番茄产量、养分吸收和氮素利用的影响。结果表明,氮素供应量(N)为225kg·hm~(-2)时番茄的产量最高,但随着施氮量的增加,番茄产量反而有所下降。增施氮肥对番茄地上部N、P、K的吸收没有明显的影响。在京郊传统生产条件下,保护地番茄生产相对合适的氮素供应水平(播前根层起始土壤无机氮含量+化学氮素用量)为510 kg·hm~(-2),但如果考虑番茄生长期间土壤氮素的矿化作用,番茄生产的氮素供应水平应为584kg·hm~(-2)。  相似文献   

Functional heterogeneity in resources within landscapes and herbivore population dynamics     

Norman Owen-Smith 《Landscape Ecology》2004,19(7):761-771

Large mammalian herbivores are notorious for their propensity towards population irruptions and crashes, yet many herbivore populations remain relatively stable. I explore how resource heterogeneity within landscapes dampens population instability, using a metaphysiological modelling approach considering patch state distributions. Resource heterogeneity is functionally stabilizing through spreading consumption away from preferred resources before these become critically depleted. Lower-quality resources act as a buffer against starvation during critical periods of the seasonal cycle. Enriching resource quality is destabilizing, even if patch diversity is maintained, because food quantity then becomes the limitation. The potential consequences of landscape fragmentation are explored using the Serengeti ecosystem, characterised by broadscale resource gradients, as a hypothetical example. Further insights provided by the model are illustrated with specific examples concerning the effects of patch scales and waterpoint distribution. A metaphysiological modelling approach enables the basic consequences of landscape heterogeneity to be distinguished from further effects that may arise from specific patch scales and configurations, without the distracting detail of spatially explicit models.  相似文献   

Validation of the specificity and sensitivity of species-specific primers that provide a reliable molecular diagnostic for <Emphasis Type="Italic">Xiphinema diversicaudatum</Emphasis>, <Emphasis Type="Italic">X. index</Emphasis> and <Emphasis Type="Italic">X. vuittenezi</Emphasis>     

Judith Hübschen  Lilo Kling  Ulrike Ipach  Volker Zinkernagel  Nathalie Bosselut  Daniel Esmenjaud  Derek J.F. Brown  Roy Neilson 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):779-788

Xiphinema diversicaudatum and X. index are vector nematode species of economic importance in viticulture regions as they can transmit Arabis Mosaic, Grapevine Fanleaf and Strawberry Latent Ringspot viruses to grapevine. Wang et al. (2003) designed species-specific diagnostic primers from ribosomal genes for both these vector species as well as a vector and a non-vector species X. italiae and X. vuittenezi, respectively. Our study aimed to confirm the specificity and determine the sensitivity and reliability of the primers for the two vector species, X. diversicaudatumand X. indexwhen challenged with closely related longidorid species and general nematode communities typical of vineyard soil. With one exception, no PCR product was observed when the primers were tested against six Longidorus, one Paralongidorus and one Xiphinema non-target species. Occasionally (three out of eight replicate PCR reactions) a weak PCR product was noted when primers for X. index were tested with L. elongatus. Furthermore, when challenged with a range of non-target nematode species comprising the nematode community typical of viticulture soil, no PCR product was amplified. An experimental dilution series of extracted DNA rigorously demonstrated that DNA from an equivalent single specimen of the target virus-vector species, X. diversicaudatum and/or X. index, could be detected amongst 1000 equivalent non-targetX. vuittenezi. Also, extracted DNA from an equivalent single target specimen was detected when added to DNA extracted from the overall soil nematode community. The primers were assessed further by using serial mixtures of actual nematodes rather than extracted DNA to simulate field soil. Using this method, a single target nematode could be detected amongst 200 non-target specimens. Given their specificity, sensitivity and reliability, it appears that these diagnostic primers will be of great benefit to phytosanitary/quarantine services related to the viticulture industry.  相似文献   

A review on breeding and genetic strategies in Iranian buffaloes (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>)     

Abbas Safari  Navid Ghavi Hossein-Zadeh  Abdol Ahad Shadparvar  Rostam Abdollahi Arpanahi 《Tropical animal health and production》2018,50(4):707-714

The aim of current study was to review breeding progress and update information on genetic strategies in Iranian buffaloes. Iranian buffalo is one of the vital domestic animals throughout north, north-west, south and south-west of Iran with measurable characteristics both in milk and meat production. The species plays an important role in rural economy of the country due to its unique characteristics such as resistance to diseases and parasites, having long productive lifespan and showing higher capability of consuming low-quality forage. In Iran, total production of milk and meat devoted to buffaloes are 293,000 and 24,700 tons, respectively. Selection activities and milk yield recording are carrying out by the central government through the Animal Breeding Centre of Iran. The main breeding activities of Iranian buffaloes included the estimation of genetic parameters and genetic trends for performance traits using different models and methods, estimation of economic values and selection criteria and analysis of population structure. Incorporating different aspects of dairy buffalo management together with improved housing, nutrition, breeding and milking, is known to produce significant improvements in buffalo production. Therefore, identifying genetic potential of Iranian buffaloes, selection of superior breeds, improving nutritional management and reproduction and developing the education and increasing the skills of practical breeders can be useful in order to enhance the performance and profitability of Iranian buffaloes.  相似文献   

Prevalence of <Emphasis Type="Italic">Haemonchus contortus</Emphasis> infection in sheep slaughtered at Jimma town municipal abattoir,Ethiopia     

Amarech Habte  Nuraddis Ibrahim 《Tropical animal health and production》2018,50(8):1865-1870

Haemonchus contortus is a parasite of major economic importance of most sheep-rearing areas of the world. A cross-sectional study was conducted from November 2015 to March 2016 with objectives of determining the prevalence and associated risk factors of Haemonchus contortus infection in sheep slaughtered at Jimma town municipal abattoir, Ethiopia. Of the total 7000 sheep slaughtered during the study time period, 384 sheep were randomly selected and examined for parasites. The overall prevalence of Haemonchus contortus infection was 264 (68.75%). Infection rate of poor body condition animals was significantly (P?=?0.000) higher than good body conditioned animals. The mean packed cell volume (PCV) values (%) of parasitemic and aparasitemic sheep were 23.73?±?3.7 SD and 37.66?±?4.736 SD, respectively. The prevalence in adult sheep (>?1 year) was insignificantly (P?=?0.653) higher than that of young sheep (≤?1 year). The highest prevalence was recorded in sheep that originated from Seka district (73.3%) and the lowest in Kersa district (63.4%) with non-significant variation (P?=?0.691). The highest monthly mean worm burdens and prevalence of Haemonchus contortus infection were recorded in November and lowest in March. The current study revealed that Haemonchus contortus infection is an important and common parasitic disease and requires special attention to its control.  相似文献   

Can treatment of <Emphasis Type="Italic">Brachiaria decumbens</Emphasis> (signal grass) improve its utilisation in the diet in small ruminants?—a review     

Eric Lim Teik Chung  Michael Predith  Frisco Nobilly  Anjas Asmara Samsudin  Faez Firdaus Abdullah Jesse  Teck Chwen Loh 《Tropical animal health and production》2018,50(8):1727-1732

Brachiaria decumbens is an extremely productive tropical grass due to its aggressive growth habit and its adaptation to a varied range of soil types and environments. As a result of the vast availability, treated B. decumbens demonstrates as a promising local material that could be utilised as an improved diet for sheep and goats. Despite the fact that the grass significantly increases weight gains in grazing farm animals, there were many reports of general ill-thrift and sporadic outbreaks of photosensitivity in livestock due to the toxic compound of steroidal saponin found in B. decumbens. Ensiling and haymaking were found to be effective in removing toxin and undesirable compounds in the grass. Biological treatments using urea, activated charcoal, polyethylene glycol, and effective microorganisms were found to be useful in anti-nutritional factor deactivation and improving the nutritive values of feedstuffs. Besides, oral administration of phenobarbitone showed some degree of protection in sheep that fed on B. decumbens pasture. In this review, we aim to determine the effect of B. decumbens toxicity and possible treatment methods on the grass to be used as an improved diet for small ruminant.  相似文献