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.     

采用灰色关联分析法综合评价国内主栽山药品种

采用灰色关联分析法,对国内7个主栽山药品种进行综合评价,以得出栽培综合性状最好表现最优秀的山药品种。试验结果表明:在7个品种中,农大长山药1号综合性状最好,其他品种从好到坏依次为平凉山药、蠡县麻山药、汾阳山药、济宁米山药、太谷山药和安顺山药。农大长山药1号作为供试品种中的新型人工培育品种,栽培表现优秀,是值得大力推广的山药品种。     

山药多糖提取工艺的研究

以水为提取剂进行山药多糖的提取,利用正交法确定山药水溶性多糖的最佳提取条件为:粉碎程度100目、料液比1︰45、提取温度45℃、提取时间2.5h。此条件下多糖得率最高,是提取山药多糖较理想的工艺条件。山药水溶性多糖提取液经透析纯化,干燥后为深黄色固体,得率为2.97%。     

土壤耕深对寒地山药生长发育及产量的影响

为确定适宜的土壤耕深度,为优质、高产栽培提供科学依据.以兴凯湖山药为试材,通过4种不同耕作深度的处理,研究了土壤耕作深度对寒地山药生长发育及产量的影响.结果表明:耕作深度对山药地上部茎叶的生长及生育时期无影响,但对地下部块根的延长生长、加粗生长,以及产量的形成具有显著的作用,土壤耕作深度以110 cm为宝.     

不同细毛山药品种矿质元素含量的研究

为了探明细毛山药不同品种在矿质营养成分方面的特性,收集了当地主栽的5个细毛山药品种进行了试验。结果表明,细毛山药矿质元素含量具有品种间差异性。不同品种之间干物质含量有着显著差异,以TG品种最高,NT品种最低。试验对5个品种的矿物质含量进行了分析,发现在试验的所有品种内,矿物质含量的变化趋势都表现为:钾>镁>钙>钠>铁>铝>锌>铜>锰>镍>铬>铅>钴;但在不同品种间,各个元素含量有明显差异,其中大量元素钾、镁的含量在品种间有显著差异;在微量元素中,铁、锰、铬的含量也在品种间有显著性差异;其他所测量的各种矿质元素在品种间没有显著性差异。同时,还测量了砷、硒、镉3种元素,可能由于含量太低而没有检出。对1~3年不同种龄的山药产品进行了元素分析,发现其元素含量趋势与上述一致,但没有发现种龄对山药矿质元素含量有显著影响。     

膨大素对淮山药的应用效果研究

以淮山品种"桂淮2号"和"铁棍山药"为试材,采用定向结薯栽培方式,在结薯初期以200 mg/L(A)4、00 mg/L(B)6、00 mg/L(C)3个浓度的去豆膨大素进行叶面喷施处理,对照喷清水,研究去豆膨大素处理后对淮山薯块养分、余零子产量、薯块产量及品质产生的效应。结果表明:去豆膨大素处理后"桂淮2号"和"铁棍山药"的氮含量差异不明显,全磷和钾含量都是B处理得到显著提高;去豆膨大素处理后2个品种的薯粗得到显著提高,而薯长没有明显差异,但以B处理的效果最好;去豆膨大素处理后2个品种的粗蛋白、水分、鲜淀粉、可溶性糖含量差异均不明显。由此可说明,去豆膨大素主要促进淮山薯块膨大,通过增加薯粗来提高产量,而且以400 mg/L浓度处理的效果最好。     

山药多酚的功能及开发应用展望

本文介绍了山药及其多酚的组成,论述了山药多酚的功能并对山药的应用进行了展望。     

科棉3号纤维品质特性及成纱质量的研究

本文系统分析了科棉3号品质的特点．探索了其纺纱性能。试验结果表明．科棉3号纤维长度30mm以上、麦克隆值A级、比强度25gf/tex以上．达到高品质棉的标准。从纺织性能看，科棉3号与苏棉9号相比，无论是纺C14.5还是JC14.5纱，条干水平均有明显的改善，条干变异系数下降0．8％～1．7％，细节降低4—40个／km，断力强度增加3．4—4．0gf/tex，粗节和强力变异系数均有不同程度的下降，唯一的缺点就是棉结相对较多，对成纱外观质量有一定负面影响。     

生物有机肥对防治山药根茎腐病和促进山药生长的研究

为了探讨生物有机肥(BOF)对山药根茎腐病的防治效果和促生效果,在山药根茎腐病重发地块进行了田间小区试验.结果表明:施用生物有机肥的处理Tl(CK+450 kg/hm2 BOF)、T2(CK+750 kg/hm2 BOF)和T3(CK+1050kg/hm2 BOF)与CK相比,山药根茎腐病病斑的长度分别减小了65.1％、77.2％、78.0％,病斑所占的比例分别下降了67.6％、80.0％、81.7％,对山药根茎腐病有很好的防治效果;山药块茎的鲜重分别增加了15.2％、32.0％、37.1％,块茎长度分别增加了6.0％、11.3％、19.5％,块茎茎粗分别增加了10.9％、23.6％、50.9％,山药产量提高了15.3％、32.2％、37.3％;T1、T2和T3与CK相比,细菌的数量分别增加1.04、1.31、1.41倍、放线菌的数量分别增加1.09、1.18、1.71倍,真菌的数量分别减少了21.9％、46.9％、50.0％,从而改善土壤微生态环境.施用生物有机肥不仅可以明显减少山药根茎腐病的发生,同时对山药有较强的促生效果,具有广阔的应用前景.     

Woody legumes as live support systems in yam cultivation

This paper reports on the use of three leguminous perennials (Leucaena leucocephala, Flemingia macrophylla and Gliricidia sepium) as live support systems in yam cultivation. In a planting arrangement in which yam rows alternated with rows of the woody species the tuber yields per ha were 3.4 (leucaena), 5.3 (flemingia) and 10.1 (gliricidia) ton fresh weight. TUKEY's L.S.D. value equalled 2.9 ton. Leucaena leucocephala is unsuitable as live support since the species shows a strong competitive power expressed in terms of leaf productivity and relative density of the root mass in the upper soil stratum, the zone explored by the yam crop. Flemingia macrophylla is unsuitable as support species mainly because of its structural weakness: Its branches do not sufficiently lignify to carry the yam leaf mass. The significantly higher tuber yield of the yam crop grown with Gliricidia sepium is a function of specific properties of the tree species: Low leaf productivity, a relatively weakly developed root system and an open architecture, which leaves sufficient space for a yam crop grown in association.