Eradication of targeted species of internal parasites

Eradication can be defined as the permanent reduction to zero of the incidence of infection caused by a specific agent as a result of deliberate efforts. Eradication strategies must be designed to increase access to and utilization of veterinary and animal health support services beyond that normally achieved by routine services. Consequently, before undertaking an eradication program, proponents must be certain that they can be sure of a commitment of resources sufficient to complete the project. A helminth eradication campaign would require the application of anthelmintics to all hosts at a level aimed at killing heterozygote resistant individuals. This strategy runs counter to the prevailing opinion that resistance to chemicals will always occur and control schemes should accept some production loss by letting a proportion of parasites escape selection (in refugia) and thereby increase the useful life of the chemical. Under certain circumstances, environmental constraints may make some species of parasitic nematodes vulnerable to an eradication program. Anthelmintics have been used to exploit these constraints in past control programs and have lead to local eradication of several species of gastro-intestinal parasitic nematodes. Also, there are at present eradication programs for nematode parasites of human that are based on anthelmintic treatment. However, the suppressive pesticide treatment required to bring about the virtual elimination of species is a high-risk strategy and should only be undertaken if eradication is an achievable goal. It is also important to plan an exit strategy if eradication fails.     

通过分子标记辅助选择技术选育携有水稻白叶枯病抗性基因Xa23的水稻株系

 通过杂交和分子标记辅助选择技术,将亲本材料18113携有的水稻白叶枯病抗病基因Xa23导入亚种间恢复系H705和优质恢复系H706。利用EST标记C189检测目的基因,在18113/H705 F3和18113/H706 F3株系中,分别获得71和52份携有Xa23纯合基因型恢复系。采用水稻白叶枯病Ⅳ型小种代表菌株浙173进行剪叶接种,分别鉴定出61和44份抗病株系,它们的分子标记辅助选择准确率分别为85.92%和84.61%。研究结果表明,C189是检测Xa23基因的有效分子标记之一,不过,其假阳性的几率高于理论交换率的现象还有待于进一步研究。     

高产优质抗病花生新品种湛油75选育及配套栽培技术

湛油75是湛江市农业科学研究所于1997年采用汕油523作为母本、粤油79作父本杂交选育而成。2004-2005年参加广东省花生品种区域试验,2007～2008年参加全国（南方区）花生区试,2009年参加国家南方区花生品种生产试验,均表现高产、优质等特性,2008年1月通过广东省农作物品种委员会的审定;2010年1月通...     

玉米超高产育种

玉米超高产育种应主攻子粒产量指标,围绕产量指标"三高一广"开展选育,即自交系的高配合力,自交系及杂交种均高度耐密,高度的综合抗性,有广泛的适应性。     

凉山州安宁河谷地带早春马铃薯品种的筛选

选择近年在安宁河谷地带种植观察表现产量高、品质好的凉薯97、会-2、抗青9-1、丽薯6号、米拉、川凉薯5号共6个品种进行了早春马铃薯品种筛选试验。结果表明:在安宁河谷地带选择会-2、川凉薯5号、抗青9-1和丽薯6号4个品种种植均可获得较高产量和产值。     

氮磷钾不同配比模式对水稻性状及产量的影响

通过对北镇地区氮磷钾不同配比模式对水稻的影响效果进行试验。结果表明,推荐施肥区、习惯施肥与推荐施肥搭配区的产量高于其他处理的水稻产量,肥料利用率高些,增产效果好,经济效益显著。其中以推荐施肥N-14.2、P-7、K-7的配方最佳,但此施肥配方易受土壤条件和气候制约,需因地制宜,予以应用。在生产实际中,氮磷钾肥施用以1/3氮肥、全部磷肥、2/3钾肥做底肥,后期追施2/3氮肥和1/3钾肥为最佳施肥模式,能够达到高产、稳产、高效的目的。     

玉米新杂交种鲁单718的选育研究

简要介绍了玉米新杂交种鲁单718的选育背景、选育过程及品种特征特性等,对于鲁单718的成功选育提出了育种目标、选系技术与方法、杂种优势模式等方面的思路。     

龙牧807苜蓿选育报告

从龙牧803(Medicago sativa L.cv.Longmu 803)苜蓿群体中选择优秀单株,通过无性扦插繁殖,3次混合选择、开放授粉及品种比较试验、区域与生产试验,历经12年育成龙牧807苜蓿(Medicago sativa L.cv.Longmu807)新品种。该品种株型直立,在黑龙江省地区4月中下旬返青,生育期120 d左右,开花期株高75.7~105.3cm,成熟期株高98.5~133.8 cm。2年生干草产量为11739.14 kg·hm^-2,比对照龙牧803苜蓿(9797.99 kg·hm^-2)增产17.10%;种子产量284.60 kg·hm^-2,比对照(230.00 kg·hm^-2)增产18.25%。初花期粗蛋白含量19.38%,适口性好,饲用品质优良。其抗性强,生态适应性广,适宜在黑龙江省各地及毗邻省区推广种植。     

Trophic consequences of postfire logging in a wolf–ungulate system

Controversy surrounds postfire logging, often because of negative effects on snag-dependent wildlife species. Few studies, however, have examined effects on early-seral species that may benefit from postfire logging, nor effects on trophic relationships. We studied the effects of postfire logging on trophic dynamics between wolves (Canis lupus), three ungulate species and ungulate forage biomass during the first 3 years in a large burn in the Canadian Rockies, Alberta, Canada. We examined plant biomass and ungulate responses to two treatments (post- and prefire logging) compared to a burned but unlogged area (control). We evaluated resource selection for the three treatments by elk (Cervus elaphus) using radiotelemetry and for deer (Odocoileus spp.), moose (Alces alces), and, secondarily, elk using pellet counts. Elk resource selection was modeled as a function of the trade-off between wolf predation risk and herbaceous forage biomass to test for trophic impacts of postfire treatments. Postfire logging had transient effects on total herbaceous biomass; while forb biomass was reduced, increases in graminoid biomass more than compensated by the third year. Prefire logging areas were dominated by a few species, but had generally higher forage biomass by the third year. Ungulates avoided postfire and prefire logged areas despite greater herbaceous biomass. Only when we considered elk resource selection as a function of both forage and wolf predation risk was the extent to which trophic interactions affected by postfire logging revealed. Wolves selected proximity to roads and the higher forage biomass associated with postfire logging in open logged areas. This translated to the highest predation risk for elk in postfire logged areas. Thus, ungulates avoided postfire logged areas because of human alteration of top-down predation risk despite enhancements to bottom-up forage biomass. Managers should consider trophic consequences of postfire logging on the interactions among species when gauging logging effects on terrestrial ecosystems. Making use of existing roads, minimizing the construction of new roads, and managing road removal following postfire logging will help mitigate the negative effects of postfire logging on terrestrial ecosystems.     

青岛市园林绿化树种的调查研究

本项研究通过生态调查法调查了青岛市内356条道路的行道树;公园、山头、小区、学校等28个地块92个样方的乔木和灌木。通过调查发现法桐、黑松、刺槐、雪松、樱花、小龙柏、金叶女贞、大叶黄杨、红叶小蘖等使用率较高,数量较多;白皮松、侧柏、糯米条、溲疏等生长较好,但是应用比较少。对青岛市园林绿化树种的总体应用状况作出了一个较为客观公正的评价。