以湖南和湖北大豆[Glycine max（L.）Merr.]为例分析影响遗传多样性评价的因素

以不同来源大豆种质为材料进行基因组SSR分析，探讨大豆遗传多样性研究方法，旨在为科学评价大豆种质资源提供参考。当取样比例相同时，湖北大豆的遗传丰富度显著高于湖南大豆，但两省大豆遗传多样性指数之间没有显著差异。当取样量相同时，利用随机取样法比较，湖南大豆的遗传多样性显著高于湖北，而利用聚类取样比较，两省大豆的遗传多样性没有显著差异。在遗传多样性指数相同情况下，湖北大豆的遗传丰富度显著高于湖南大豆。取样数与三个遗传多样性评价参数（等位变异数、Shannon指数、He）之间均达到显著和极显著相关。以湖南大豆为例，估算出在大豆SSR遗传多样性分析中，至少需要50~60个样本，即占总体9.0%~10.8%的取样比例，才能代表总体的遗传变异。提出在评价大豆遗传多样性时，应用大豆样本数对其遗传多样性指数计算公式进行修正，建议将Shannon指数计算公式改为H＝－lnN ∑P_i lnP_i (N为样本数)。根据修正公式分析，结果表明，湖北大豆的遗传多样性高于湖南大豆。     

海岛棉遗传多样性的SRAP标记分析

利用SRAP标记, 选用132对带型清晰的多态性引物, 对我国引入海岛棉以来培育的36个国内品种及20个国外品种进行遗传多样性分析。共检测到419个多态性位点, 每组合的多态性条带数从2~9不等, 平均为3.17。利用NTSYS-pc 2.10e 软件采用Jaccard’s相似系数和UPGMA方法进行聚类分析。结果表明, 大部分具有亲缘关系的品种聚在同类中, 说明其结果与系谱具有一定的相符性; 56个品种的平均遗传相似系数为0.497, 变化范围在0.312~0.876之间, 说明我国海岛棉品种在分子水平上存在较大差异; 我国3个育种时期育成品种的平均相似系数依次为0.501、0.507和0.548, 表明我国现在育成的品种相对于早期品种遗传多样性在逐渐降低。这些结果为我国海岛棉育种提供了有益的参考。     

水稻种质资源的分子鉴定和育种利用

水稻种质资源包括栽培稻、野生稻及育种材料等各种类型,是水稻新品种选育、生物技术研究以及农业生产的物质基础。中国具有丰富的水稻种质资源,但其利用率却不高,原因之一就在于传统方法不能够对其进行准确的研究评价。理想的分子标记具有稳定性高、重复性好、检测简单快速和共显性遗传等优点。本文综述了分子标记技术在水稻种质资源遗传多样性分析、重要功能基因的挖掘、品种DNA指纹库的构建及分子育种材料遗传基础的拓展等方面的作用,旨在为更充分的将分子标记技术应用于水稻种质资源的鉴定和分子育种提供参考。     

东北地区水稻种质资源遗传多样性分析

以能够代表东北地区水稻当前育种动态的区域试验品种(系)为试材,利用SSR标记分析了东北稻区水稻种质资源地区问和品种间的遗传多样性差异以及亲缘关系.结果表明,东北稻区整体的遗传多样性狭窄,明显低于国内其他稻区水平.在103个多态性位点上共检测到303个等位基因,平均每个位点只有2.94个,并且等位基因分布也极不均匀.不同染色体问的遗传多样性分析结果表明,Chr.6、Chr.9、Chr.11三条染色体的多态性位点分布较均匀且多态性信息含量也较多,整体遗传多样性丰富程度高于其他染色体.结果还发现,三个省份中黑龙江地区的品种整体纯合程度最高的,吉林次之,辽宁最低.东北三省水稻遗传多样丰富程度排序是:黑龙江>吉林>辽宁.通过遗传聚类分析显示,吉林与黑龙江的整体亲缘关系较近,相对地与辽宁较远.     

DNA profiling and genetic diversity of Korean soybean (<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merrill) landraces by SSR markers

Approximately 7,000 accessions of Korean soybean (Glycine max (L.) Merrill) landraces, largely composed of three collections, the Korea Atomic Energy Research Institute’s soybean (KAS), the Korean Crop Experiment Station’s soybean (KLS) and the Korean Agricultural Development and Technology Center’s soybean (KADTC) collections, have been conserved at the Rural Development Administration (RDA) genebank in Korea. The accessions within collections were classified based on their traditional uses such as sauce soybean (SA), sprouted soybean (SP), soybean for cooking with rice (SCR), and OTHERS. A total of 2,758 accessions of Korean soybean landraces were used to profile and to evaluate genetic structure using six SSR loci. A total of 110 alleles were revealed by at the six SSR loci. The number of alleles per SSR locus ranged from 9 to 39 in Satt187 and Satt_074, respectively. The number of alleles ranged from 87 in the KADTC collection to 96 in the KLS collection, and from 63 in the SCR group to 95 in the SP group. Nei’s average genetic diversity ranged from 0.68 to 0.70 across three collections, and 0.64 to 0.69 across the usage groups. The average between-group differentiation (G _st) was 0.9 among collections, and 4.1 among the usage groups. The similar average diversity among three collections implies that the genetic background of the three collections was quite similar or that there were a large number of duplicate accessions in three collections. The selection from the four groups classified based upon usage may be a useful way to select accessions for developing a Korean soybean landrace core collection at the RDA genebank. DNA profile information of accessions will provide indications of redundancies or omissions and aid in managing the soybean collection held at the RDA genebank. The information on diversity analysis could help to enlarge the genetic diversity of materials in breeding programs and could be used to develop a core collection.     

中国88个马铃薯审定品种SSR指纹图谱构建与遗传多样性分析

为对马铃薯品种鉴别、优良杂交组合选配提供分子水平上的依据,利用SSR标记构建了中国2000-2007年审定的88个马铃薯品种的指纹图谱并进行了遗传多样性分析。以138对SSR引物对16份遗传差异较大的马铃薯材料的基因组DNA进行了扩增,筛选出10对多态性高、谱带清晰的引物。利用10对SSR引物对全部供试材料进行扩增及电泳检测,共检测到135个等位位点,其中133个为多态性位点,多态性比率达98.52%。每对SSR引物扩增出的等位位点数7~22个,平均13.5个,多态性信息量变化范围为0.7604~0.9375,平均0.8501。通过对电泳检测结果的统计分析,利用S180、S25、S7、S151、S184及S192等6对引物构建了88份供试材料的SSR指纹图谱。聚类分析表明,在相似系数0.620处,所有供试材料被被聚为一类,在相似系数0.652处,81.8%的材料仍然聚在一起,从分子水平上表明供试材料遗传基础非常狭窄。聚类分析结果与供试材料系谱来源有较好一致性,同一栽培区域育成的品种在不同程度上聚在一类。     

濒危东乡野生稻遗传多样性及其生态保护学研究进展

东乡野生稻蕴含大量优异性状和有利基因,是栽培稻遗传改良重要的种质资源。然而“东野”正面临着急剧减少甚至是灭绝的威胁,为此评价并保护现存“东野”的遗传多样性刻不容缓。同时“东野”的多样性研究对解析其遗传进化机理以及在水稻育种上的利用有着重要意义。为此,综述了近年来不同保存方式、不同年份、不同世代以及与其他生态类型野生稻和栽培稻等多个角度有关“东野”遗传多样性及其保护研究成果。通过对存在的相关问题分析,笔者认为应该建立科学统一的遗传多样性评价体系,并提出了“东野”遗传多样性研究前景和生态保护建议。     

Isozyme studies of genetic diversity and evolution in Hippophae

Summary To provide information on the genetic variation, differentiation and evolution in Hippophae seed samples of 25 populations from China, Finland and Russia were electrophoretically analyzed. Of six loci investigated, four were good genetic markers for identifying species and subspecies. The percentages of polymorphic loci per population were 40.3% and 62.5% at 0.95 and 0.99 polymorphic criteria respectively. The mean number of alleles per locus per population was 2.1. Total genetic diversity in the material was 0.4614. Genetic diversity partitioning showed that there was a large amount of diversity residing within geographical populations (0.1354), between subspecies within species (0.1046) and between species (0.2566) but not between geographical populations (0.0114). There were nearly twice as many negative fixation indices as positive ones in Hippophae populations. The phylogenetic tree agreed very well with botanic classifications of the species and subspecies and their geographical distributions, and quantitatively presented the genetic relationships of 25 populations. A detailed view of the evolutionary stages in Hippophae showed clearly a general decline of similarity as evolutionary divergence continued, which further explained the evolution process in Hippophae.     

南宁市十字花科蔬菜害虫天敌群落结构分析

南宁市十字花科蔬菜害虫天敌群落物种有70种(类)，隶属7目26科。主要有青翅隐翅虫(Paederus fuseipes)，长足虻(Dolichopodidae)、小菜蛾绒茧蜂(Cotesta plutellae)、八斑鞘蛛(Coleoserma octumaculalum)、食虫沟瘤蛛(Ummeliata insecticeps)、浅斑近微蛛(Eperigone fredeorum)和肖蛸(Tetragnatha)。蜘蛛的种类和数量皆为无公害和常规栽培两类菜地天敌之最。群落的多样性和均匀度偏低，优势种突出。文中揭示了两类菜地天敌群落的相似性及其结构特点和时间动态。认为占两类菜地节肢动物群落物种的53．44％和占个体数量的24．96％的菜地害虫天敌资源，是值得进一步研究和保护利用的自然生物控制因素。     

间作系统根-土互作与连作障碍缓解

现代农业大面积单一作物连作种植和农药化肥的大量施用问题较为严重,造成农田生态系统日趋简单和脆弱,使作物病害发生频繁,病害流行周期越来越短,连作障碍严重发生。间作作为中国传统农业的精髓,具有增产、提高养分资源利用效率的优势。文章旨在明确间作缓解连作障碍的机制,以期为寻求缓解连作障碍的措施奠定基础。从寄主营养及生理变化、诱导寄主抗性、养分高效利用、改善土壤理化性状、抑制病原菌及土壤微生物多样性等方面对间作缓解连作障碍机制的最新进展进行了总结,明确了间作缓解连作障碍的机理,同时展望了间作缓解连作障碍的未来重点研究方向,以期为指导中国农业生产,实现农业的可持续发展提供理论和技术支持。