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71.
有色黏虫板对柑橘木虱的监测及防治研究进展 总被引:1,自引:0,他引:1
柑橘黄龙病是柑橘生产中的重大病害,随着其在全球范围内的传播蔓延,该病已成为近年来柑橘生产和研究中普遍关注的热点。柑橘木虱(Diaphorina citri Kuwayama)是传播柑橘黄龙病菌(Candidatus Liberibacter asiaticus)的主要虫媒,对柑橘木虱种群的准确监测与有效防控是控制柑橘木虱传播黄龙病的关键所在。有色黏虫板是一种利用昆虫趋色性,对小型飞行昆虫进行监测与诱杀的重要物理防治手段。有色黏虫板同样适用于监测和诱捕柑橘木虱,但黏虫板的颜色、光源、气候条件、悬挂黏虫板的植物种类及其挥发性信息化合物成分等都会影响黏虫板对柑橘木虱的诱集效果。本文在综合国内外柑橘木虱防控技术的基础上,将近年来利用有色黏虫板,监测与防控柑橘木虱的最新进展进行综述,并对有色黏虫板的发展前景给予展望。 相似文献
72.
本研究建立了一种基于雷达图分析稻米食味评价的新方法.该方法选择胶稠度、碱消值、粒型、直链淀粉含量和蛋白质含量等5个对稻米食味品质影响较大的理化指标作为雷达图分析的评价指标.各个评价指标经无量纲化处理后用于绘制雷达图.为消除指标排列顺序不同引起的差异,本文采用雷达图的平均周长和平均面积作为特征向量构建评价参数,并对10个参试样品的食味品质进行综合评价.结果表明,采用本文建立的雷达图分析法得到的食味评价排序与常规感官评价法的排序基本一致,表明本文建立的雷达图分析法适用于稻米食昧品质的初步评价. 相似文献
73.
2006-2014年,应用病土盆栽方法,对来自于12个省(市)的779份大豆种质资源进行了大豆胞囊线虫3号生理小种的抗病性鉴定。鉴定材料来源于吉林省539份、黑龙江省58份、辽宁省51份、山西省16份、内蒙古17份、河北省10份、北京市42份、安徽省5份、广西壮族自治区14份、河南省17份、山东省6份、江苏省4份。从中选出19份抗病种质,占鉴定总数的2.44%,分别是FY001-3、W93155、JH229、HJ01-1900、W94128-8、YX04-6561、W7491、W201102-25、Q30、Q31、HK6、HK7、BN9、CM2008-12、JY407、Q32、Q28、Q33、BN10,按抗病种质在各省份鉴定材料中所占的比例来看,山东省大豆种质抗病比例最高,占83.33%,其次是黑龙江省占15%。这些品种(系)的农艺性状优良,可直接作为抗性亲本应用于育种。 相似文献
74.
Effects of stocking density on the performance of brown shrimp Farfantepenaeus californiensis co‐cultured with the green seaweed Ulva clathrata 下载免费PDF全文
《Aquaculture Research》2017,48(6):2803-2811
The brown shrimp Farfantepenaeus californiensis and the seaweed Ulva clathrata, both native to north‐west Mexico, were co‐cultured in lined ponds during 18 weeks. The aim of this study was to evaluate different stocking densities (10, 20, 30, 40 and 50 per m2) in terms of shrimp yield to see if the co‐culture method results in shrimp yields suitable for commercial production. The presence of Ulva results in good water quality and allows culture of brown shrimp with low water exchange (10% weekly) and with low nitrogen and phosphorus content in discharged water. The final weight and specific growth rate (SGR) in shrimp between 10 and 30 per m2 were significantly higher (12.5–12.0 g and 4.56–4.53% day−1 respectively) than 40 and 50 per m2 (9.1 and 8.6 g, and 4.31% and 4.26% day−1 respectively). Total shrimp biomass generated in 30 or more shrimp per m2 was significantly higher (2.7–3.1 t ha−1) compared with 10 and 20 shrimp per m2 (1.0 and 2.0 t ha−1 respectively). The lowest feed conversion ratio (FCR) (0.97) was shown in the 10 shrimp per m2 case, and the highest FCR was seen with 50 shrimp per m2 (1.37). Shrimp survival ranged between 71% and 81%, where the highest mortality was shown in 50 shrimp per m2. The results show that the co‐culture method can result in commercially interesting yields, suggesting that 30 shrimp per m2 is the best stocking density for co‐culturing F. californiensis with U. clathrata, based on the shrimp performance. 相似文献
75.
76.
An economically based evaluation index for perennial and short‐term ryegrasses in New Zealand dairy farm systems 下载免费PDF全文
D. F. Chapman J. R. Bryant M. E. Olayemi G. R. Edwards B. S. Thorrold W. H. McMillan G. A. Kerr G. Judson T. Cookson A. Moorhead M. Norriss 《Grass and Forage Science》2017,72(1):1-21
Grazed pastures based on ryegrass species provide most of the feed for dairy cattle in New Zealand. There are many cultivars of perennial (Lolium perenne), annual and Italian (L. multiflorum), and hybrid (L. boucheanum) ryegrasses available for dairy farmers to use in pasture renewal. This study describes an index which ranks ryegrass cultivars relative to a genetic base according to the estimated economic value (EV) of seasonal dry matter (DM) traits. A farm system model was used to derive EVs (Grazed pastures based on ryegrass species provide most of the feed for dairy cattle in New Zealand. There are many cultivars of perennial (Lolium perenne), annual and Italian (L. multiflorum), and hybrid (L. boucheanum) ryegrasses available for dairy farmers to use in pasture renewal. This study describes an index which ranks ryegrass cultivars relative to a genetic base according to the estimated economic value (EV) of seasonal dry matter (DM) traits. A farm system model was used to derive EVs ($ ha?1 calculated as change in operating profit divided by unit change of the trait) for additional DM produced in different seasons of the year in four regions. The EV of early spring DM was consistently high across all regions, whereas EV for late spring DM was moderate to low. Genotype × environment analysis revealed significant reranking of DM yield among ryegrass cultivars across regions. Hence, separate performance values (PVs) were calculated for two mega‐environments and then combined with the corresponding season and region EV to calculate the overall EV for twenty‐three perennial ryegrass and fifteen short‐term ryegrass cultivars. The difference in operating profit between the highest ranked and lowest ranked perennial ryegrass cultivar ranged from $556 ha?1 to $863 ha?1 year?1 depending on region. For short‐term ryegrasses used for winter feed, the corresponding range was $394 to $478 ha?1 year?1. Using PV for DM yield, it was estimated that plant improvement in perennial ryegrass has added $12–$18 ha?1 year?1 (depending on region) operating profit on dairy farms since the mid‐1960s. 相似文献
77.
西藏鱼类增殖放流初报 总被引:4,自引:0,他引:4
西藏土著鱼类生长缓慢、性成熟晚并对环境变化高度敏感。近年来,受过度捕捞、水利工程建设等人类活动的影响,西藏渔业资源面临越来越大的压力。开展增殖放流活动是恢复当地渔业资源和生态平衡的重要手段。本文介绍了西藏鱼类增殖放流概况、苗种来源、放流实施、效果评估情况,分析了目前存在的基础研究不足、苗种来源不稳定、缺乏技术规范、效果评估有待加强等问题。提出了加强增殖放流基础设施建设和基础理论研究、建立西藏鱼类增殖放流与效果评估技术规范、重视放流后的管理与评估工作、加强专业技术人才队伍建设的建议。 相似文献
78.
以辽宁省某尾矿库为例,基于GIS技术,利用2010年的TM遥感影像及地形图,预测该尾矿库扩容后的生态影响。分析结果显示:尾矿库扩容工程对生态的影响主要体现在土地利用、植被、生态景观和地形地貌的变化4个方面。 相似文献
79.
Conservation implications of establishment success of the Critically Endangered Twee River redfin ‘Pseudobarbus’ erubescens (Skelton, ) in an artificial impoundment in South Africa 下载免费PDF全文
Martine S. Jordaan Johannes A. van der Walt Zanné Brink Sonja Erasmus Olaf L. F. Weyl 《水产资源保护:海洋与淡水生态系统》2017,27(4):886-889
- This study reports the first known record of breeding of the Critically Endangered Twee River redfin ‘Pseudobarbus’ erubescens in an artificial impoundment. This followed an introduction of 48 individuals into a 10 ha impoundment within the species' native range more than a decade ago.
- Sampling the impoundment using three fyke nets set overnight yielded 2838 P. erubescens, which included both juveniles and adults capable of spawning. Fork length measurements of a subsample of 250 individuals ranged from 29 to 125 mm with length cohorts indicating multiple spawning events.
- This demonstrates that this species can successfully reproduce in lentic environments and suggests that artificial impoundments could be stocked to provide refugia for P. erubescens and other highly threatened small cyprinids while conservation strategies are developed to mitigate against habitat loss resulting from alien fish invasions, increased human use of water, and from climate change in rivers.
80.
Does full protection count for the maintenance of β‐diversity patterns in marine communities? Evidence from Mediterranean fish assemblages 下载免费PDF全文
Luca Appolloni Stanislao Bevilacqua Luisa Sbrescia Roberto Sandulli Antonio Terlizzi Giovanni Fulvio Russo 《水产资源保护:海洋与淡水生态系统》2017,27(4):828-838
- Although it is widely recognized that protection may enhance size, abundance, and diversity of fish, its effect on spatial heterogeneity of fish assemblages and species turnover is still poorly understood.
- Here the effect of full protection within a Mediterranean marine protected area on β‐diversity patterns of fish assemblages along a depth gradient comparing a no‐take zone with multiple unprotected areas is explored. The no‐take zone showed significantly higher synecological parameters, higher β‐diversity among depths, and lower small‐scale heterogeneity of fish assemblages relative to unprotected areas.
- Such patterns might likely depend on the high level of fishing pressure outside the no‐take zone, as also abundance‐biomass curves seemed to indicate. Results suggested that full protection could play a role in maintaining high β‐diversity, thus reducing the fragility of marine communities and ecosystems, and spatial heterogeneity may represent a reliable predictor of how management actions could provide insurance against undesirable phase shifts.