Soil Properties Required by Some Southern Africa Fruit Trees as Assessed by Discriminant Analysis

Some indigenous fruit trees, in the drylands of southern Africa are worthy of interest because of their adaptation to environmental conditions prohibitive for traditional crops. Their fruits or their derivatives are traditionally used as an additional income by rural population, but little information is available about the properties of the soils that support their growth, although this information is necessary if the trees are subjected to sustainable domestication. Several soil properties are, however, to be considered as a whole and discriminant analysis provides a helpful tool to individuate the best conditions for the tree growth. Thirty-five soil samples were taken in areas where the trees naturally grow and produce, and the analytical data of the surface layer were used to relate soil properties to tree species. Four groups of trees were well separated using two discriminant functions that takes into account both the fertility characteristics (pH, organic C, N, texture, and properties of the exchange complex) and the Fe contents and distribution among the oxide forms. The discriminant functions allow a very acceptable reclassification of the data (more than 80% of cases correctly reclassified) and the classification coefficients were used to build an empirical equation that may help to identify the most suitable tree to be introduced at a new site.     

食材还是玩物:古代鹌鹑驯养及利用考

鹌鹑作为著名的特种经济禽类,其驯化饲养已有几千年的历史。早在西周时期,鹌鹑就已经是祭祀献神的常用祭品,其后一直作为猎物与贡品被人们利用。唐代以后,鹌鹑逐渐成为皇室以及士人阶层的食材与玩物。至明清时期,"斗鹌鹑"在民间普遍盛行,鹌鹑的驯养技术得到了更广泛的实践。驯养鹌鹑和"斗鹌鹑"活动成为当时人们生活的重要内容,衍生出了具有中国传统特色的鹌鹑文化。     

Genetic structure of highland papayas (<Emphasis Type="Italic">Vasconcellea pubescens</Emphasis> (Lenné et C. Koch) Badillo) cultivated along a geographic gradient in Chile as revealed by Inter Simple Sequence Repeats (ISSR)

In Chile Vasconcellea pubescens is cropped to produce canned fruit, juice, jam and processed sweets. Additionally this species produces latex with a high level of papain, an important and valuable proteolytic enzyme with industrial applications. In this investigation seven ISSR primers were used to study the level and organization of genetic diversity in 333 samples of V. pubescens. Out of the 114 bands recorded, 63 proved to be polymorphic (P = 55.3%). At the species level, the genetic diversity was rather low (h = 0.01 ± 6,80188E-05, Shannon’s Index I = 0.16 ± 0,000148). The major portion of the genetic diversity was found within groups (65%). The genetic differentiation between the different groups was significant, as the AMOVA analysis suggested (Φ_pt = 0.35). When analysing the Northern area alone, the differentiation increased to Φ_pt = 0.40. When only the Southern area was analysed, Φ_pt decreased to 0.18, indicating greater genetic similarity among the samples. The results generated from Structure and Bayesian Analysis of Population Structure distinguished 8 genetically different groups, five of them located in the north and three in the south. The results are discussed in the light of the growers’ practices.     

山羊的起源驯化和品种形成

回顾了山羊野祖及其驯化传播过程的传统观点。以考古学、历史学和畜牧学研究结果为依据，提出了家养山羊多地起源的观点，并认为中国是山羊早期独立驯化地之一。认为各地方山羊品种形成是在自然选择和人工选择作用下长期适应的结果，中国北方地区山羊品种形成过程中包含了古代西域山羊的血统。     

我国驯化、引种栽培的食用菌种类

综述了我国已经驯化、引种栽培的食用菌种类．共20科80余种食用菌驯化、引种栽培食用菌的中文名称、拉丁学名、别名、最早出菇的文献报道。     

选择牵连效应分析：发掘重要基因的新思路

作物在长期进化过程中，除自然选择外，还经历了两次大的人工选择，即人工驯化选择和育种选择，使栽培种与野生种之间、现代品种与古老的地方品种之间在群体遗传结构及性状上形成了很大的差异；在基因组中，一些承受强选择作用的基因在群体中的多样性显著降低，同时这些基因附近区域的遗传多样性也明显下降。在遗传学中将这种对个别基因的选择导致其侧翼区域遗传多样性降低的现象称之为选择牵连效应（Hitchhiking effect，也称选择搭载效应）。通过大群体多位点的扫描分析，可找到一些发生选择牵连效应的基因组区段，利用标记/性状关联分析（Marker/Trait association analysis），就可发现这些区段所控制的重要性状；对这些区段进行精细扫描和分析，即可找到一些决定重要农艺性状的基因，并发现优异等位变异，从而为重要基因的克隆和作物品种的分子设计奠定基础。各大作物高密度分子标记连锁图谱的绘制完成、高通量基因型分析技术体系的建立，为利用选择牵连效应分析、通过标记/性状之间的关联，寻找和定位一些重要基因奠定了基础。本文在查阅文献的基础上，结合作者的研究，以小麦株高、千粒重、磷的吸收和利用等性状为例，就选择牵连效应分析的基本思路、方法进行了讨论，以起到抛砖引玉之作用。     

乌兰布和沙漠东缘野生蔬菜资源

为了充分利用与保护野生蔬菜资源,对乌兰布和沙漠东缘的野生蔬菜资源及利用状况进行了调查。结果表明,乌兰布和沙漠东缘有野生蔬菜90种,分属于19科36属,其中菊科、百合科、黎科及蒿属、葱属、香蒲属的种类较多。常见的野生蔬菜有枸杞、苋菜、灰绿藜、地肤和马齿苋。乌兰布和沙漠东缘的野生蔬菜总体上利用率低,但个别种类如沙葱、沙芥却存在着过渡采集。乌兰布和沙漠应积极开展野生蔬菜资源方面的开发及保护,加快野生蔬菜的驯化栽培。     

野生白芨种苗快繁与驯化试验研究

对野生白芨进行组培快繁研究,结果表明:MS+2.5 mg/L 6-BA+0.2 mg/L NAA诱导效果最好,诱导率可达98％;MS +IAA2.5mg/L+2.5 mg/L 6-BA+2.0 mg/L NAA诱导增殖的效果最好,培养40 d后增殖率可达3.8倍;1/2MS+0.01 mg/L NAA1 +0.01 mg/L IAA有利于生根,且植株长势健壮.炼苗基质以60％腐叶土+30％珍珠岩+10％蛭石为佳;炼苗温度23～28℃,空气相对湿度80％～90％有利于提高炼苗成活率.