Diversity, distribution and management of yam landraces (Dioscorea spp.) in Southern Ethiopia

Yam (Dioscorea spp.) is widely grown in many parts of Ethiopia and plays a vital role in local subsistence. Nevertheless, its diversity has not been studied in detail. A survey covering 339 farm households and eight districts was conducted in the major yam growing regions of Southern Ethiopia to investigate the diversity and distribution of yam landraces using structured and semi-structured questionnaires. A total of 37 named landraces were recorded, with a range from one to six (mean 2.9) on individual farms. Farmers’ decisions regarding the number and type of landraces maintained was influenced by tolerance of the landraces to drought, their maturity time and market demand. Most landraces had limited abundance and distribution, and only a few dominant landraces were widely grown. There was also variation amongst districts with respect to diversity, distribution and abundance of the landraces found. In the majority of the localities surveyed, farmers reported a decreasing trend in the number of landraces maintained on individual farms and in the overall yam production. Besides, in those limited areas where yam production is expanding, farmers are increasingly relying on a few selected landraces that mature early. Findings of this study suggest that local farmers in Wolayita and Gamo-Gofa zones maintain considerable yam diversity that remains to be further explored for sustainable utilization and conservation of the available genetic resources.     

面向国家级生态市建设的深圳市水资源可持续利用对策研究

随着经济社会的快速发展,深圳市水资源紧缺矛盾日益突出。介绍了深圳市的水资源现状和水资源开发利用情况,按照国家级生态市建设和可持续发展要求,分析了当前深圳市水资源开发利用所面临的问题。提出了构建节水型产业体系,加强污水处理设施建设,优化配置水源,完善水资源管理体系等水资源可持续利用对策。     

论现阶段高校图书馆的信息服务工作

回溯建库工作、信息资源整合、文献信息资源的开发和利用是现阶段图书馆工作的主要内容之一,本文就现阶段高校图书馆的信息服务工作提出一些粗浅的看法。     

Resistance Evaluation of Some Commonly Used Maize Germplasm Resources to Fusarium Diseases in China

【Objective】 Maize ear rot, stalk rot and sheath rot are the three common Fusarium diseases in maize producing areas in China, and there is a trend of serious mixing occurrence in recent years. The main pathogens of the three major diseases are F. verticillioides, F. graminearum and F. proliferatum. Planting resistant varieties is the most economical and effective method to control this kind of diseases. The objective of this study is to screen out the maize resistant germplasms to ear rot, stalk rot and sheath rot, and to provide references for scientific breeding and rational layout of maize varieties.【Method】 Sixteen common inbred lines of maize including B73, B37, Zheng 58, Chang 7-2, Qi 319 and so on were selected to inoculate F. verticillioides, F. graminearum, and F. proliferatum on maize ears, stalks and sheaths, respectively. The suspension spores of F. verticillioides were injected into healthy maize ears along the filament channel with a continuous syringe at silk stage. The stem of the first aboveground segment of healthy maize was pinned and then injected with the suspension spores of F. graminearum. The suspension spores of F. proliferatum were injected into the sheath of the aboveground 2-5 internodes along the base of healthy maize sheath. Sterile water was used as control. In 2016 and 2018, experiments were conducted in fields to evaluate the disease index of ear rot, sheath rot and the lesion areas of stalk rot, so as to evaluate the resistance level to the ear rot, stalk rot and sheath rot.【Result】 The tested inbred lines Ji 853, OH43 and X178 were moderate resistance to ear rot, 13 of the tested inbred lines such as B73, B37, PH6WC, Ye 478, Zheng 58, 9058, Chang 7-2, Xun 928, Mo17, A619, PH4CV, Qi 319 and 13-1077 were sensitivity or high sensitivity to ear rot; 8 of the tested inbred lines including Qi 319, PH4CV, Mo17, 9058, B37, B73, Chang 7-2 and 13-1077 were moderate resistance and high resistance to stalk rot, 7 of the tested inbred lines such as Zheng 58, Ye 478, PH6WC, Xun 928, Ji 853, A619 and OH43 were sensitivity or high sensitivity to stalk rot; 15 of the tested inbred lines such as B73, B37, Zheng 58, Ye 478, PH6WC, 9058, Chang 7-2, Ji 853, Xun 928, Mo17, A619, PH4CV, OH43, Qi 319 and 13-1077 were moderate resistance or resistance to sheath rot. According to the population of 16 inbred lines, Reid group was susceptible to ear rot. Lancaster group and Tangsipingtou group were resistant to sheath rot. The resistant levels of other groups to Fusarium diseases dispersed to a large extent, and there was no obvious regularity.【Conclusion】 The tested inbred lines Ji 853 and OH43 showed moderate resistance or resistance to sheath rot and ear rot, 8 of the tested inbred lines including Qi 319, PH4CV, Mo17, 9058, B37, B73, Chang 7-2 and 13-1077 showed moderate resistance, resistance or high resistance to sheath rot and stalk rot, but the materials with good resistance to all three diseases had not yet been screened, and other germplasm resources needed to be further screened.     

旱季橡胶树魏克汉种质资源胶乳生理参数分析

以131份达到开割标准的魏克汉种质资源为试验材料，于2018年4月下旬开始割胶，5月下旬（旱季）采取单株胶乳，测定胶乳中的无机磷、硫醇、蔗糖、干胶、总固形物含量等参数，结合单刀胶乳产量和胸径围进行分析。结果表明，旱季橡胶树种质资源胶乳产量与胶乳中硫醇含量、总固形物含量的关系最为紧密。胶乳产量较高或较低的种质资源胶乳中硫醇含量对应较高或较低，总固形物含量对应较低或较高，反之亦然。相关性分析显示，胶乳产量与硫醇含量呈极显著正相关（P＜0.01），与无机磷、蔗糖、干胶、总固形物含量呈负相关，胸径围与胶乳产量呈正相关。其他季节胶乳产量与胶乳生理参数的关系还待进一步研究。     

木荷的经济价值及培育措施

指出了木荷是云南的珍贵树种,种源稀少,通过森林资源调查,发现了南华县雨露乡铅厂村委会有部分零星资源分布,保护种质资源,意义重大。通过梳理,阐述了木荷资源在南华县的分布特征、经济价值和园林应用,提出了充分利用木荷资源的具体措施,制定了种苗培育的实施方案,以有利于城市绿化建设,创建秀美河山。     

我国内蒙古西部地区国有林场经营现状与发展问题探析

国有林场在内蒙古林业生态建设中具有骨架作用,是祖国生态安全屏障的重要组成部分与支撑点,也是贯彻落实生态文明建设,践行“绿水青山就是金山银山”理念不可或缺的重要实施主体。在深入了解与掌握内蒙古自治区西部地区6个市国有林场经营现状的基础上,总结归纳了内蒙古西部地区国有林场经营的特点,深入分析了内蒙古西部地区国有林场面临的问题与困境,并探讨解决这些问题的途径,为国有林场今后的发展提出了合理化建议。     

政策认知、执行力度与资源化利用满意度——基于河北省380家生猪养殖主体调研数据(上)

参与主体对于政策的评价是衡量政策实施效果的重要指标，探明政策参与主体满意度影响因素有助于了解主体自身需求，从而提高政策实施水平。文章基于对河北省380家生猪养殖主体调研数据，运用多元有序Logistic回归方法，分析生猪养殖主体自身政策认知以及相关政策执行力度对畜禽养殖主体废弃物资源化利用满意度的影响。结果表明：养殖主体资源化利用政策了解程度能够显著提升其资源化利用政策满意度；仅考虑养殖主体政策参与力度，随着参与力度增加，满意度亦会显著提升。但综合考虑其他因素，参与力度对于满意度提升效果则不再显著；养殖主体感知政策执行力度增加不利于政策满意度提升。此外，生猪养殖主体废弃物资源化利用政策了解程度增加，可以显著提升其报告资源化利用政策“满意”可能性。而单纯提高资源化利用政策执行力度并不能显著提高养殖主体资源化利用政策满意度。因此，要提高养殖主体政策满意度，应多渠道提升宣传力度，鼓励养殖主体积极参与，提高其参与意识，不断改善现有政策执行方式。     

规模养殖场畜禽粪污处理和资源化利用

畜牧作为推动农业发展的动力,可促进其发展现代化农业,提高农民收入。但是,随着畜牧业发展,加剧粪污污染问题,应加强粪污处理及资源化利用,以达到保护环境的目的。该文主要从畜禽粪污处理和资源化利用重要性切入,分析目前粪污处理与资源化利用方式,提出相应保障措施,进而推动畜牧业实现绿色发展。     

3种龙胆科植物的资源分配对策

选择青藏高原东缘同一生境类型下具有不同交配系统特点和不同传粉者丰度的3种龙胆科植物湿生扁蕾(Gentianopsis paludosa)(自花授粉)、祁连獐牙菜(Swertia przewalskii)(高昆虫访问异花授粉)和线叶龙胆(Gentiana farreri)(低昆虫访问异花授粉)为对象,研究其资源分配特征。结果表明,1)3种植物的花粉胚珠比例(P/O)存在显著差异(P0.05),湿生扁蕾的P/O显著低于另外两种异花授粉植物的(P0.05),祁连獐牙菜的P/O显著低于线叶龙胆的(P0.05);2)3种植物的繁殖分配比例存在差异,湿生扁蕾的繁殖分配比例显著高于另外两种异花授粉植物的(P0.05),线叶龙胆的繁殖分配比例显著高于祁连獐牙菜的(P0.05);3)在繁殖分配比例与个体大小关系上,湿生扁蕾与其个体大小不存在显著相关关系(P0.05),而另外两种异花授粉植物则与其各自个体大小之间存在显著负相关关系(P0.05)。研究表明,交配系统类型和传粉者丰度与植物的资源分配模式有关,尽管3种植物的繁殖绝对投入量都与其个体大小显著正相关(P0.05),但自花授粉植物相对于异花授粉植物具有较高的繁殖分配比例,并且这种较高的繁殖分配比例不受个体大小影响,这种高繁殖投入的资源分配模式可能与自花授粉植物具有繁殖保障,从而降低其繁殖代价有关。