北美落基山自然风光与动植物纪事

北美洲落基山脉纵贯加拿大西南和美国西北部,跨越北极带、寒带和温带高原气候带,是全球著名山脉之一。有奇特的高原地貌、世界最大的冰原、众多冰河、瀑布、高原湖泊、温泉及间歇喷泉等自然景观,以及多种植被、特有动物,每年吸引来自世界各地的众多游客。美国、加拿大政府和联合国教科文组织重视环保,在落基山脉建立众多国家公园,其中有7处划定为《世界遗产目录》《世界遗产公园》。国家公园重视环保,订立各种保育措施,值得借鉴。     

盐碱地渗水调配养殖南美白对虾技术

本文介绍了利用黄河三角洲地区丰富、闲置的重盐碱地,经过合理调配水质,在反复试验的基础上设计出一套合理的健康养殖技术方案,实施了大面积南美白对虾盐碱地健康养殖。尤其是通过在用盐碱地渗出的咸水与淡水混合调配成的,盐度为5～20的养殖用水中,添加一定浓度的钾离子,有效提高了虾苗的成活率。     

Biodiversity conservation in human-modified landscapes of Mesoamerica: Past, present and future

Mesoamerica provides a unique context for biodiversity conservation in managed landscapes because of its geography, history of human intervention, and present conservation and development initiatives. The long and narrow form of the Mesoamerican landmass, and its division by a central mountain range, has served as both a bridge and a barrier. Conservation efforts in Mesoamerica are unique for the emphasis they place on regional connectivity through the Mesoamerican Biological Corridor and on biodiversity conservation in managed landscapes. The emphasis on conservation in agricultural systems has fostered innovations in payment for ecosystem services, and provides novel insights on the functional role that biodiversity plays in the provisioning of ecosystem services. The increasing rate of economic development in the region and the advent of new payment for ecosystem service schemes have provided new opportunities for forest regeneration and restoration. However, the small scale of private landholdings and the diversity of land uses featured in the region, while contributing to biodiversity conservation due to their structural and floristic complexity, present challenges for biodiversity monitoring and management.     

美国转基因作物田间试验频次分析

本研究通过对美国转基因作物田间试验频次分析揭示转基因作物研发的概貌和规律.采用EXCEL"数据透视表与数据透视图"软件,对美国转基因作物田间试验数据库和世界经济合作组织转基因作物田间试验数据库近20年数据进行统计分析.结果表明,至2008年9月止,美国转基因作物田间试验累计达13782次,涉及158种作物,10大类性状和98家公司或研究机构.1987-2008年间,审批的田间试验次数先呈直线上升,其后稳定在每年1000次左右.试验物种以玉米、大豆、棉花为主,分别占45.8%、9.7%和6.4%.涉及的主要性状有抗除草剂、抗虫和品质性状.62.7%的转基因作物田间试验由孟山都和国际先锋等五家私人公司完成.分析认为,只有经济价值高、安全性好、技术成熟、消费者容易接受的转基因作物才拥有更广阔的发展前景.建议我国加强非粮食作物转基因技术的研究.     

A methodology for evaluating a location as a selection site for an international plant breeding program

Summary A method for comparing locations as selection sites based upon their abilities to predict yield and disease reaction over a target region is proposed. The probability of coincidence in selection for a site is defined as the probability for a line selected at the site to be selected at other sites within the region. The probability of divergence in rejection is defined as that associated with regional selection of a line given that is discarded by the site where selection is being conducted. The ideal selection site would maximize the probability of coincidence in selection and minimize the probability of divergence in rejection. The method is illustrated using a set of data from the rice yield nurseries of the International Rice Testing Program for Latin America planted under the rainfed conditions of Central América and México during the period 1978–1984. Five locations were compared for their predictive ability in selecting for the rainfed rice growing region, based on yield and disease reaction. Selection for yield was defined as performance superior to the best check in each location. Selection for disease reaction was based on an index derived from the Standard Evaluation System for Rice for diseases of regional importance. Locations varies 10–15 percent in their selection coincidence with the region for both yield and disease selection criteria applied independently.     

黑龙江省乡土杨树与美洲黑杨杂交新品种的选育技术

通过试验和评比,选出了生长性、抗性强的4个杂种无性系,其无性系为苇河大青杨×盖县3、带岭大青杨×山海关2、方正小叶杨×盖县2、苇河大青杨×盖县2.     

美国·韩国及台湾农业现代化对我们的启示

发达国家和地区解决农业现代化问题的经验是一笔宝贵的世界遗产,值得仔细地发掘和整理,为我们所用。以美国、台湾和韩国为例分别进行了研究。     

Folk experiments

Folk experiments in agriculture are often inspired by new ideas blended with old ones, motivated by economic and environmental change. They tend to save labor or capital. These notions are illustrated with nine short case studies from Nicaragua and El Salvador. The new ideas that catalyze folk experiments may be provided by development agencies, but paradoxically, the folk experiments are so common that the agencies that inspire them usually pay little attention to them. Some folk experiments are original, but others simply copy innovations that farmers have seen somewhere else. Unlike formal scientific research, in which results are consistently written, folk experiments are rarely “inscribed,” because the results are for use by individual farmers and need not be shared with an audience.     

Reverse leasing and power dynamics among blue agave farmers in western Mexico

We examine changing production relations in the Mexican tequila industry to explore the ways in which large industrial firms are using “reverse leasing arrangements,” a form of contract farming, to extend their control over small agave farmers. Under these arrangements, smallholders rent their parcels to contracting companies who bring in capital, machinery, labor, and other agricultural inputs. Smallholders do not have access to their land, nor do they make any of the management decisions. We analyze the factors that have led some producers to participate in reverse leasing arrangements, while allowing other producers to continue farming independently. In addition, we look at the ways in which farmers are responding to these new production relations and constraints and the strategies that they are using to regain control over the production process.

Traditional Mexican Agricultural Systems and the Potential Impacts of Transgenic Varieties on Maize Diversity

The discovery of transgenes in maize landraces in Mexico, a center of diversity for this crop, raises questions about the potential impact of transgene diffusion on maize diversity. The concept of diversity and farmers’ role in maintaining diversity is quite complex. Farmers’ behavior is expected to have a significant influence on causing transgenes to diffuse, to be expressed differently, and to accumulate within landraces. Farmers’ or consumers’ perceptions that transgenes are “contaminants” and that landraces containing transgenes are “contaminated” could cause these landraces to be rejected and trigger a direct loss of diversity. Mauricio R. Bellon is a human ecologist working in the Economics Program of the International Maize and Wheat Improvement Center (CIMMYT) in Texcoco, Mexico. He received his MSc and PhD in ecology at the University of California, Davis. His current research includes projects that deal with on-farm conservation of maize, gene flow in traditional farming systems, and the impact of improved germplasm in the livelihoods of poor farmers. Julien Berthaud is a population geneticist working for the Institut de Recherche pour le Développement (IRD). He received his PhD in plant science at the University of Paris 11. His current research includes projects related with the dynamics of genetic diversity, especially in traditional maize farming systems.