Structure of AIIozymatic Diversity of Ten Temperate and Adapted Exotic Breeding Populations of Maize （Zea mays L.）

Ten temperate and adapted exotic breeding populations of maize were studied with electrophoretic techniques. Three isozyme systems coded by nine allozyme loci were used for evaluating the genetic variability within and among populations. The results revealed that 78.57% of allozyme loci were polymorphic. Low allelic variation with a mean number of 1.84 alleles per locus per population was detected. But, these populations still maintained higher level of heterozygosity; moreover, the exotic populations had greater gene diversity than the temperate populations. All the populations were non-panmictic with negative Wright＇s fixation indexes （-0.091— -0.424）. The tropical BS 16 was typified by maximum allelic richness, percent of polymorphic loci and heterozygosity. More than 93% of the gene diversity maintained within populations, and the genetic differentiation among populations was low （0.002—0.191）. Multivariate analysis demonstrated that the tropical BS29 diverged from other populations in the reverse direction. The temperate BS9 and tropical BS16 were divergent each other, and highly differentiated from other temperate and tropical populations, consequently, these two populations would be analogically postulated as potential germplasms to establish new heterotic groups for temperate maize breeding programs.     

不同类型玉米种质群体的SSR遗传多样性分析

利用SSR标记对人工合成群体、地方种质群体和热带、亚热带群体等3种不同类型群体进行遗传多样性分析,26对SSR引物在供试群体内共扩增出184个等位位点.多态性位点数、多态位点比例、基因型数以及遗传距离等分析表明,三类群体均具有较丰富的遗传变异,且热带、亚热带群体内个体间的遗传距离大于地方种质群体和人工合成群体.这一结果说明热带、亚热带群体内的遗传变异较大,面人工合成群体与地方种质群体内的遗传变异则相对较小且基本相当.     

陕西栓皮栎天然群体同工酶遗传多样性研究

利用凝胶电泳法研究了陕西省境内3个栓皮栎天然群体的遗传变异和分化情况,测定和分析过氧化物酶（POD）,酯酶（EST）,苹果酸脱氢酶（MDH）和乙醇脱氢酶（ADH）的多态位点百分率、等位基因平均数、等位基因频率、平均期望杂合度和基因分化系数,结果表明：陕西栓皮栎天然群体的遗传变异绝大部分在群体内,占总变异的95．1％,群体间变异仅占总变异的4．9％,多态位点百分率为75％,等位基因平均数为2．708,平均期望杂合度为0．388．     

热带温带玉米群体产量性状遗传力及遗传方差分量的剖析

【目的】评估2个热带群体和7个温带群体的育种价值，并在这些群体之间寻找新的杂种优势模式，为利用这些种质提供有用的科学信息。【方法】采用9个群体的双列杂交设计，得到36个杂交组合；2002～2003年分别在河南省安阳和湖北省十堰进行田间鉴定，获取产量相关性状的试验数据，用混合线性（AD）模型和MINQUE（1）法（minimum norm quadratic unbiased estimation，最小范数二阶无偏估算法）对各性状遗传力、遗传方差分量及其占总表型变异的比率、群体的加性遗传效应和显性遗传效应进行剖析。【结果】联合分析结果显示：各性状的大多数遗传效应值都达到显著（P≤0.05）或极显著水平(P≤0.01)。各遗传方差分量的效应对小区产量贡献大小是显性>显性与环境互作>加性与环境互作>加性；各性状狭义遗传力大小为穗行数>行粒数>穗长>出籽率>百粒重>小区产量，加性效应最好的4个群体是Suwan1（31.69）、Stay green c4（25.44），WBM C4（14.15）和中综4号（10.29）；而显性效应比较好的4个组合为3×6（883.65）、1×3（572.20）、1×2（404.2376）和6×7（384.59）。【结论】在温带玉米育种中Suwan1和Stay green c4是最有利用价值的外来种质，它们都与BSSS C9构成杂种优势模式。在育种实践中，可以把Suwan1和Stay green c4杂交重组，并与BSSS C9构成一对温带和热带种质的杂种优势模式，可以进一步进行相互轮回选择。     

中国鲎3个地理群体遗传多样性的等位酶分析

应用等位酶技术对漳浦、连江和温州3个地理群体的中国鲎遗传多态性进行分析.实验结果发现：6个酶系统的10个位点中有6个为多态性位点,共获得21个等位基因;大部分位点在3个群体中偏离Hardy-Weinberg平衡;在物种水平上,有效等位基因数为1.635,观察杂合度为0.456,期望杂合度为0.306,香侬指数为0.486,表明中国鲎的遗传多样性较高;F-统计量（FST）平均为0.0475,表明中国鲎遗传差异主要存在于群体内;遗传一致度平均为0.969,遗传距离平均为0.0315,表明中国鲎群体间遗传分化较低;基因流平均为5.0120,显示群体间存在较大的基因交流.由此认为3个群体属于同一个繁殖群体.在进行鲎物种保护的同时,要加强对其遗传多样性的保护.     

矮慈姑一个自然居群的遗传多样性

采用垂直板聚丙烯酰胺凝胶电泳技术和等位酶分析方法，研究了矮慈姑一个自然居群的遗传多样性。根据9个酶系统16个等位酶位点的检测结果，表明矮慈姑的遗传多样性属中等水平。矮慈姑自然居群的多态位点百分率P=25．0，平均每位点等位基因数A=1．4375，平均多态位点等位基因数Ap=2．500，等位基因有效数Ae=1．3093，平均预期杂合度He=0．1327，平均观察杂合度Ho=0．1948，固定指数F=-0．4684。实际观察到的杂合体比率高于理论预期杂合体比率，居群表现为杂合体过量。     

三个群体罗氏沼虾线粒体COI基因的遗传多样性分析

运用PCR方法,扩增罗氏沼虾缅甸原种F1代、广西选育群体和江苏养殖群体的线粒体DNA上的细胞色素氧化酶(Cytochrome oxidase subunit I,COI)基因,在此基础上选用10种限制性内切酶对扩增产物进行限制性片段长度多态(RFLP)分析。三个群体共发现2个多态位点,11种酶切图谱,3种基因型。三群体的多态座位比例、平均杂合度和基因型多样性指数分别为:缅甸原种F122.2%、0.0556、0.0472,广西选育群体22.2%、0.0400、0.0398,江苏养殖群体11.1%、0.0106和0.0083,群体间遗传差异未见显著。根据群体间遗传距离构建UPGMA聚类关系图,显示广西选育群体和江苏养殖群体间的遗传关系较近,而与原种F1群体的遗传关系较远。     

林芝云杉天然群体同工酶遗传多样性分析

采用水平切片淀粉凝胶电泳试验对西藏林芝云杉12个群体的10个酶系统进行测定,共获得20个谱带清晰、分离良好的位点,对这20个位点的统计分析表明:林芝云杉群体的多态位点百分率(P)=55.00%,每个位点的等位点基因数(Na)=1.900 0,每个位点的有效等位基因数(Ne)=1.609 3,观测杂和度(Ho)=0.229 1,期望杂和度(He)=0.2648,遗传一致度(I)=0.4168;这些指标在12个群体的均值略低于种级水平。对12个群体的遗传分化进行研究,群体间遗传分化系数(Gs,t)=7.406 5%,有92.593 5%的变异存在群体内;群体间的遗传分化度(Fs,t)=8.424 7%,仍远远小于群体内的91.535 7%;基因流(Nm)=7.011 9>4,可以代替遗传漂变防止群体间分化的发生。对12个群体两两之间的遗传距离进行研究,遗传一致度(I)的变动幅度为0.9475～0.997 9,平均值为0.980 1;遗传距离(D)变动幅度为0.002 1～0.054 0,均值为0.019 1。     

三个群体罗氏沼虾线粒体COI基因的遗传多样性分析

运用PCR方法,扩增罗氏沼虾缅甸原种F1代、广西选育群体和江苏养殖群体的线粒体DNA上的细胞色素氧化酶(Cytochrome oxidase subunit I,COI)基因,在此基础上选用10种限制性内切酶对扩增产物进行限制性片段长度多态(RFLP)分析。三个群体共发现2个多态位点,11种酶切图谱,3种基因型。三群体的多态座位比例、平均杂合度和基因型多样性指数分别为:缅甸原种F122.2%、0.0556、0.0472,广西选育群体22.2%、0.0400、0.0398,江苏养殖群体11.1%、0.0106和0.0083,群体间遗传差异未见显著。根据群体间遗传距离构建UPGMA聚类关系图,显示广西选育群体和江苏养殖群体间的遗传关系较近,而与原种F1群体的遗传关系较远。     

Genetic Diversity of Maize Populations Developed by Two Kinds of Recurrent Selection Methods Investigated with SSR Markers

Two cycles of biparental mass selection （MS） and one cycle of half-sib-S3 family combining selection （HS-S3） for yield were carried out in 2 synthetic maize populations P4C0 and P5C0 synchronously. The genetic diversity of 8 maize populations, including both the basic populations and their developed populations, were evaluated by 30 SSR primers. On the 30 SSR loci, a total of 184 alleles had been detected in these populations. At each locus, the number of alleles varied from 2 to 14, with an average of 6.13. The number and ratio of polymorphic loci in both the basic populations were higher than those of their developed populations, respectively. There was nearly no difference after MS but decreased after HS-S3 in both the basic populations in the mean gene heterozygosity. The mean genetic distance changed slightly after MS but decreased in a bigger degree after HS-S3 in both the basic populations. Analyses on the distribution of genetic distances showed that the ranges of the genetic distance were wider after MS and most of the genetic distances in populations developed by HS-S3 were smaller than those in both the basic populations. The number of genotypes increased after MS but decreased after HS-S3 in both the basic populations. The genetic diversity of intra-population was much more than genetic diversity of inter-population in both the basic populations. All these indexes demonstrated that the genetic diversity of populations after MS was similar to their basic populations, and the genetic diversity was maintained during MS, whereas the genetic diversity of populations decreased after HS-S3. This result indicated that heterogeneity between some of the individuals in the developed populations increased after MS, whereas the populations become more homozygotic after HS-S3.     

红壳色文蛤选育群体遗传多样性的微卫星分析

【目的】了解群体选育过程中红壳色文蛤（Meretrix meretrix）选育群体的遗传多样性变化及世代遗传分化情况,为文蛤育种计划的可持续性提供理论依据。【方法】以江苏黄文蛤原种（SY）、江苏红文蛤原种（SR）及5个红壳色文蛤选育群体（SRF₁~SR5F₅）为研究对象,利用15对微卫星引物对各文蛤群体基因组DNA进行PCR扩增,然后通过Gel-Pro32 4.0、PopGen 32和MEGA 6.0等在线软件分析7个文蛤群体的遗传多样性。【结果】从7个文蛤群体中共检测出766个等位基因,每个微卫星位点在每个群体中检测出3~18个等位基因,且等位基因数（Na）随选育世代增加呈下降趋势。15个微卫星位点的平均多态信息含量（PIC）在0.575~0.630,均属于高度多态性位点。7个文蛤群体的平均观测杂合度（Ho）为0.442~0.502,平均期望杂合度（He）为0.629~0.680,群体中63.81%的微卫星位点偏离Hardy-Weinberg平衡,表明各微卫星位点存在一定程度的杂合子缺失;群体内近交系数（F_is）范围为-0.0157~0.7409,平均为0.2777,表明文蛤群体内存在一定程度的近交水平;群体间遗传分化系数（F_st）平均为0.0455,即文蛤群体变异中仅有4.55%是由不同群体间的基因差异所产生,而95.45%的变异来源于群体内部;各群体的基因流（Nm）为0.9002~18.9478,平均为8.8065,说明7个文蛤群体间的遗传分化较低。UPMGA聚类分析发现7个文蛤群体聚类呈两大支,江苏红文蛤原种及其选育群体聚为一支,而江苏黄文蛤原种（SY）独自聚为一支。【结论】经过5代人工选育的红壳色文蛤选育群体虽然较基础群体其遗传多样性指数略有下降,但并未导致各选育群体的遗传结构发生改变,仍具有较高的遗传多样性。在连续的选择育种计划中,应增加亲本养殖环境多样化,避免因人工繁育的亲本和养殖群体规模较小引起遗传漂移或近交衰退而致使某些等位基因缺失,导致后代的遗传结构发生改变。     

小慈姑克隆多样性与居群分化

采用聚丙烯酰胺凝胶电泳和等位酶分析方法,测定了小慈姑4个自然居群的克隆多样性,结果表明小慈姑克隆多样性水平较高。在种群水平上的克隆大小(Ne)为1.670 3,基因型比率(PD)为0.598 7,克隆的基因型多样性Simpson指数(D)为0.990 1,克隆的基因型分布均匀性Fager指数(E)为0.781 1。不同居群之间在多态性位点的数目、分布以及等位基因的表现上具有较大的差异,并且居群间的遗传分化与地理因素有关。     

不同凡纳滨对虾养殖群体的微卫星遗传多样性分析

【目的】明确不同凡纳滨对虾（Litopenaeus vannamei）养殖群体间的遗传信息丰富度和遗传分化程度,为构建适应上海独特气候对虾品种繁育计划中的交配系谱分析提供参考依据。【方法】选用13对微卫星引物对来自厄瓜多尔恒兴对虾养殖公司2个养殖场（Pesquera和San Alfonso）共9个凡纳滨对虾养殖群体进行遗传多样性分析,探究不同群体间的遗传信息丰富度和遗传分化程度。【结果】13个微卫星位点在9个凡纳滨对虾养殖群体中检测到的等位基因数（Na）为2～6个,共有37个等位基因,多态信息含量（PIC）为0.1292～0.6799,平均为0.3326。在13个微卫星位点中,仅有1个微卫星位点（TUMXLV9.116）呈高度多态性,有4个微卫星位点（TUMXLV10.147、TUMXLV5.45c、TUMXLV10.191c和TUMXLV10.96）呈低度多态性,其余8个微卫星位点呈中度多态性。9个凡纳滨对虾养殖群体的观测杂合度（Ho）为0.2225～0.3662,平均为0. 2915;期望杂合度（He）为0.3317～0.4539,平均为0. 3974;Hardy-Weinberg平衡指数（D）为0.0214～0.4214,其中San Alfonso P23群体和Pesquera P23群体的D相对更接近于0,其基因型分布接近于Hardy-Weinberg平衡状态。9个凡纳滨对虾养殖群体的F_st平均值为0.1259,说明有12.59%的遗传分化来源于群体间,而87.41%的遗传分化来自群体内部;群体间的平均基因流（Nm）为1.7356,表明遗传漂变未能主导种群遗传结构的变化。在9个凡纳滨对虾养殖群体间,以Pesquera 29群体与Pesquera 15群体的遗传距离最大（0.2426）,San Alfonso 23群体与Pesquera 23群体的遗传距离最小（0.0215）;基于遗传距离的UPGMA聚类分析结果表明,9个凡纳滨对虾养殖群体可分为两大类,其中Pesquera 29群体和San Alfonso 12群体独立聚为一类。【结论】在9个凡纳滨对虾养殖群体中存在观测等位基因丢失现象,且遗传多样性较低,群体间分化程度为中等水平。因此,可通过引进不同地区拥有不同遗传背景且亲缘关系较远的群体作为亲本,以丰富子代群体的遗传多样性。     

Genetic Diversity of Chinese Temperate and Exotic Tropical,Subtropical Quality Protein Maize Inbreds by SSR Markers

Information on genetic relationship is of great value to maize (Zea mays L.) breeding. The objectives of this study were: 1) to classify 22 quality protein maize (QPM) inbreds into different groups by using simple sequence repeats (SSR) markers, which included exotic tropical, subtropical and domestic temperate QPM and normal maize inbreds; 2) to examine the consistency of grouping results obtained from SSR, specific combining ability (SCA) analysis,and genetic backgrounds of these inbreds. A set of 39 polymorphic SSR primers was selected from 70 primer pairs, which detected 136 alleles among the 22 lines. The mean polymorphism information content was 0.55. Based on analysis of genetic similarities, five groups were identified including Luda Red Cob, Sipingtou, Reid, Lancaster and a miscellaneous group with several tropical inbreds which could not be classified into the above four groups. The results generally agreed with previous results based on analysis of yield combining ability and pedigree data.     

海南两个自然保护区野生荔枝遗传多样性研究

采用常规聚丙烯酰胺凝胶电泳技术,对海南吊罗山和霸王岭两个国家级自然保护区野生荔枝等住酶遗传多样性进行了研究.13个酶系统、18个酶位点的检测结果表明,两个自然保护区野生荔枝具有较低的居群间遗传变异水平和较高的居群内遗传变异.吊罗山保护区野生荔枝的遗传多样性参数为:P=61.1%,A=2.05,He=0.27.霸王岭居群野生荔枝的遗传多样性参数为:P=61.1%,A=2.05,He=0.28.两个群体的遗传分化极小,GST=0.040.居群间遗传一致度较高,I=0.977.共检测到8个稀有等位基因.两个自然保护区的野生荔枝均有各自特有的稀有等位基因,都应采取措施予以保护.     

6个玉米人工合成群体的育种潜势分析

 【目的】系统评价6个玉米人工合成群体的育种潜势，为进一步改良利用提供合理方案。【方法】采用群体性状表型鉴定、配合力测定以及SSR标记对群体进行综合分析。【结果】多数性状与季节互作不明显，群体间多数性状差异极显著。多数农艺、经济性状的GCA群体间存在显著或极显著差异，少数经济性状的SCA组合间存在显著或极显著差异。26对SSR引物在供试群体内共扩增出246个等位位点。多态性位点数、多态位点比例、基因杂合度以及遗传距离等分析表明，除群体P1外，各群体遗传重组比较充分，群体内具有较丰富的遗传变异，且群体间遗传距离大于群体内遗传距离。【结论】群体P4、P2和P7除自身遗传变异较为丰富外，主要经济性状GCA较高，优于对照高产组合出现次数较多，育种潜力较大。群体P1、P3和P5 经济性状GCA低，优于对照高产组合出现次数相对较少，需进行必要的改良。     

新疆核桃8个天然群体遗传多样性的SSR评价

[目的]为进一步建立新疆核桃种质资源的分子指纹鉴定体系奠定基础,为制定新疆核桃资源的有效保育和利用策略提供科学依据,并为深入研究新疆栽培与野生核桃资源间的系统关系提供实验数据.[方法]应用12对稳定、适用性好的SSR引物对新疆南北疆核桃的8个栽培及野生群体的230份样品进行扩增,研究其遗传多样性.[结果]12对SSR标记揭示了新疆核桃丰富的遗传多样性:等位基因93个,平均多态性带比率96.77;,平均Nei多样性指数(H)0.315 1,平均Shannon多样性指数(Ⅰ)0.382 0.8个新疆核桃群体的变异主要来源于群体内,群体间分化较小,遗传分化系数仅为0.172 0.估测的群体间基因流(Nm)为1.712 6,表明新疆8个核桃群体之间存在适度的基因交流,种子的传播或人为实生选种以及杂交育种可能是基因交流的主要原因.对新疆核桃8个群体的Nei多样性指数(H)与Shannon多样性指数(Ⅰ)及多态位点百分比进行分析,表明和田实生核桃的遗传多样性最高,伊犁霍城野生核桃的遗传多样性最低.采用UPGMA方法进行供试核桃的遗传距离聚类分析,8个群体被聚为两大类:和田、叶城及温宿等3个群体聚为一大类;而巩留、霍城、吐鲁番、哈密、鄯善等5个群体聚为另一大类,Mantel检测与UPGMA聚类均表明群体间的遗传距离与群体的地理距离之间具有较高的相关性.[结论]新疆核桃有着较高的遗传多样性水平,同时揭示了新疆核桃属植物的遗传变异、群体扩散及其地理系统发育进化等方面的规律,在此基础上,认为在进行遗传多样性保护和种质资源的保存时,应充分重视群体内不同类型个体的保存,同时也要在分布区不同区域内保存不同的群体.     

粤黄鸡分化品系血液蛋白质多态性基因频率的变化

本试验采用醋酸纤维薄膜电泳和聚丙烯酸胺凝胶电泳方法测定了粤黄鸡4个分化品系(群体)以及石歧杂鸡和杏花鸡的血液蛋白质多态性,观察了多态性血液蛋白质基因频率的变化,根据基因频率计算出6个群体相互之间的相似系数和标准遗传距离及各群的平均杂合度,分别以系统聚类分析和主分量分析方法对这种变化进行研究。结果表明,4个粤黄鸡分化品系大多数多态性血液蛋白质基因频率相近,少数出现品系(群体)间差异,而相似系数和遗传距离说明品系(群体)间分化与选育目的相符;系统聚类分析显示4个粤黄鸡分化品系(群体)与石歧杂鸡间关系较为密切;与杏花鸡相对地较为疏远,主分量分析却清楚地表明了粤黄鸡从石岐杂鸡中的分化以及与杏花鸡的区别。这两种分析方法结果相互补充,而两者的不一致有待进一步研究。另外,平均杂合度似乎也表明了品系(群体)选育程度的差异。     

Genetic diversity analysis of black locust (Robinia pseudoacacia L.) distributed in China based on allozyme markers approach

Using starch gel and polyacrylamide gel electrophoresis, the genetic diversity of 19 populations of black locust (Robinia pseudoacacia L.) distributed in China has been evaluated based on seven allozyme systems. Among the 14 enzyme loci studied, 12 of them showed polymorphic, giving a total of 40 alleles. The average allelic number (A) and the average effective allelic number (Ae) were 3.004 and 2.178, whereas the average of expected heterozygosity (He) and the observed heterozygosity (Ho) were 0.525 and 0.440, respectively. The total genetic differentiation (H _T ) in the 19 populations tested was 0.536, including 0.515 within population (H _S ) and 0.021 among populations (D _ST ). The mean coefficient of genetic differentiation (G _ST ) was 0.038, indicating that 3.8% of genetic differentiation was resulted from the populations, and the rest from those within the population. The genetic distance among the 19 populations was small, ranging from 0.015 to 0.065. Cluster analysis based on AVERAGE showed that populations with closer geographical distribution had higher genetic similarity than that in populations with far away distribution. There was no evident geographic differentiation pattern in Chinese black locust populations at a biochemical level.