利用SSR研究不同国家桃育成品种的遗传多样性

利用34对SSR分子标记对来自不同国家的56份桃育成品种进行遗传多样性分析。筛选的13对SSR引物共检测出226个等位基因,其中多态性等位基因为222个。桃群体的平均Nei’s基因多样度为0.224,Shannon遗传多样性表型指数为0.367,说明桃总群体遗传变异较低;基因分化系数为0.081,与AMOVA分析结果8.13%相近,说明2者遗传变异以群体内遗传变异为主;基因流值为5.657,则说明不同国家间桃育成品种交流比较频繁。根据Nei’s基因多样度和Shannon遗传多样性表型指数2指标所得,欧美品种群遗传变异最高,其次为中国,最后为日本。UP-GMA聚类分析结果表明,品种间的遗传距离与系谱关系基本吻合。     

基于SRAP分子标记的桂花品种亲缘关系研究

 利用相关序列扩增多态性( SRAP) 分子标记, 以柊树[Osmanthus heterophyllus ( G. Don. )P. S. Green ] 和华东木犀(Osmanthus cooperi Hemsl. ) 为对照种, 研究了桂花(Osmanthus fragrans Lour. )88个品种、1个野生种的亲缘关系, 18对SRAP引物共获得296个位点, 其中248个为多态性位点, 多态性比率达83.78%。平均每对引物组合产生16.4个位点和13.8个多态性位点。其中, 银桂品种群的Shanon信息指数( 0.3412) 和遗传多样性指数( 0.2191) 最高。遗传变异估算表明: 桂花遗传分化系数为52.95% , 大部分变异存在于品种群之间, 说明品种群体间遗传分化高。聚类分析结果表明, 以遗传相似系数0.762为截值, 可将91份种质分成6类; 各品种群的品种往往聚在一起; 四季桂品种群与其他品种群遗传距离较远; 色质较深的金桂往往与丹桂品种群的多个品种聚在一起。基于SRAP分子标记的聚类结果与基于形态的传统分类学的结果基本相符。     

蟠桃种质SSR标记的遗传多样性分析

以38个蟠桃品种和9个其他类型桃品种为试材,利用24对位于桃参考图谱上8个连锁群的SSR引物进行了蟠桃种质资源遗传多样性研究。24对SSR引物共获得179个扩增位点,其中多态性位点171个,多态率达95.53%。蟠桃资源平均Nei’s基因多样性指数(He)为0.242 5,平均Shannon信息指数(I)为0.379 8;南方蟠桃品种群多态性位点百分率为74.30%,Nei’s遗传多样性指数为0.203 8,Shannon信息指数为0.316 3;北方蟠桃品种群的遗传多样性相对较高,多态性位点百分率为91.06%,Nei’s遗传多样性为0.244 9,Shannon信息指数为0.382 4。群体间存在较小的基因分化系数(Gst=0.065 9),遗传变异有很大一部分是来自群体内,可能与其较大的基因流Nm=7.086 1有关。UPGMA聚类分析结果表明,相似系数为0.66～0.95,在相似系数为0.67时,所有南方品种聚于同一类群,北方品种除新疆蟠桃、黄肉蟠桃及香金蟠外也聚于同一类群,聚类结果支持蟠桃多起源假说。     

利用RAPD标记分析主产地草果遗传多样性

以云南省红河州4个居群的48份草果为试材,采用RAPD分子标记技术,研究草果遗传多样性,以期为草果资源的保护及利用提供参考依据。结果表明:11条RAPD引物共扩增出139个条带,多态性条带比率(PPB)为98.56%。在群体水平上,金平居群的遗传多样性最高(PPB=82.01%),其次是绿春居群(PPB=66.91%),屏边居群(57.55%)和元阳居群(55.40%)多样性水平相对较低。草果总遗传多样性的87.67%(Hs=0.197)来自于居群内部,居群间遗传变异只占12.33%(Gst=0.123),AMOVA分析进一步证明草果的遗传变异主要存在于居群内部。遗传一致度分析表明不同居群间的遗传一致度较高,相似性系数在0.931 4～0.971 7,表明草果居群间遗传变异较小。     

中国山荆子和楸子种质资源遗传多样性和遗传结构的荧光SSR分析

采用荧光SSR分子标记对来源于中国9个省的苹果属山荆子8个种群和楸子9个种群共288份种质的遗传多样性和种群遗传结构进行了研究。结果显示:19对SSR引物对288份种质共扩增出416个多态性等位基因,平均每个位点等位基因21.895个,多态性位点百分率(PPB)为100%。山荆子和楸子共计17个种群总体的遗传多样性较高,有效等位基因数(N_e)为9.284,平均期望杂合度(H_e)为0.862,Shannon’s多样性指数(I)为2.432;种群水平上,楸子的遗传多样性水平(H_e=0.870,I=2.412,N_e=9.019)高于山荆子(H_e=0.848,I=2.350,N_e=8.652)。分子方差分析(AMOVA)表明,遗传变异主要来自种群内(95%)。种群间的遗传分化系数(F_(st))为0.278,基因流(N_m)为5.031,表明楸子和山荆子均为异交的混交类群,各个种群在过去的某个时间都可能相互发生过基因交流,抵制了由于基因漂变而导致的种群间遗传分化。通过NJ聚类和Structure分组划分类群,种群间遗传距离和类群归属与地理位置不完全相关。     

三叶悬钩子自然居群遗传多样性的ISSR 分析

 利用ISSR分子标记对云南特有植物三叶悬钩子（Rubus delavayi Fanch.）的12个居群共248个个体进行了遗传多样性分析。结果表明：16个ISSR引物共扩增到199个位点,其中185个是多态性位点,占92.96%。三叶悬钩子居群具有很高的遗传多样性水平,在物种水平上平均每个位点的多态位点百分率（PPB）为97.99%,有效等位基因数（A_e）为1.427,Nei’s遗传多样性（H）为0.267,Shannon’s多态信息指数（I）为0.417;在居群水平上PPB为62.10%,A_e为1.289,H为0.177,I为0.275。居群间基因分化系数G_st = 0.3351,与AMOVA分析的居群间遗传变异量占总量的33.03%相近,说明三叶悬钩子居群间存在一定程度的遗传分化。居群间遗传分化占总遗传变异的33.51%,居群内的遗传变异为66.49%,基因流（N_m）为0.9923。通过Mantel检测,居群间的遗传距离与地理距离不存在相关性。UMPGA聚类分析和二维主成分分析（PCA）结果一致。导致居群内高遗传变异水平原因主要是有限的基因流,而居群间较低的遗传多样性水平可能与生态破坏和生物入侵有关。     

中国板栗品种（系）DNA指纹图谱构建及其遗传多样性分析

基于SSR荧光分子标记,对中国342个板栗品种(系)构建了DNA指纹图谱,并解析了各品种群间的亲缘关系和遗传分化特征。结果表明：(1)所有SSR标记多位点匹配后的PI和PIsibs值分别为4.960×10^-20和2.395×10^-8,显示本试验所选用的标记指纹识别潜力强;对342份品种(系)构建指纹图谱,共获得338个有唯一对应关系的指纹信息,其中舒城大红袍与焦扎、双合大红袍与CSB-1两两共享了一个指纹信息,结合主要植物学性状,推测其为同物异名品种;同时发现存在大于10个位点信息差异的19份同名资源,判定其为同名异物品种。(2)两两品种群的F_st平均值为0.0224(F_st <0.05),表明品种群间遗传分化程度较低;对5个品种群进行了基因流(N_m)和AMOVA分析,遗传变异主要存在于个体内,占总变异的84%,各品种群间的平均基因流为6.592,表明资源间存在着广泛的基因交换,制约了各群体间的分化。(3)利用位点数据进行群体结构、主坐标和聚类树分析表明,板栗品种资源主要...     

基于SRAP标记的伊犁河谷野生杏群体遗传多样性研究

利用SRAP分子标记方法对伊犁河谷14个野生杏种群,212份种质资源的遗传多样性进行了研究。结果表明,12对SRAP引物共扩增出条带143条,其中122条具有多态性,多态性比率为85.31%。伊犁河谷野生杏仍然维持较高的遗传多样性水平(h=0.2411,I=0.3708,PPB=85.31%),吐尔根乡种群遗传多样性指数最高。伊犁河谷野生杏存在较高水平的种群内遗传变异(76.42%)和较低水平的种群间遗传变异,种群间存在温和稳健的基因流(Nm=1.3680)。UPGMA系统聚类和遗传结构分析均显示,伊犁河谷野生杏可划分为以霍城样本为主的类群Ⅰ,以巩留和伊宁样本为主的类群Ⅱ和以新源样本为主的类群Ⅲ,种群间遗传距离和地理距离存在具有统计学意义的相关性(r=0.2634,P0.05)。     

中国枣树干腐病菌(Botryosphaeria dothidea)群体遗传多样性的ISSR分析

【目的】从分子水平上揭示我国枣树干腐病菌群体的遗传特点,探究其遗传变异的规律。【方法】采用正交实验设计的方法,对影响ISSR-PCR扩增的4个因素进行研究。采用ISSR分子标记,对161株供试病原菌进行PCR扩增,通过Pop Gene和Arlequin软件对其群体遗传多样性和遗传分化情况进行分析。【结果】从40条ISSR引物中筛选到10条扩增多态性良好的引物,建立了适合枣树干腐病菌ISSR-PCR扩增的体系。采用该体系共在132个位点扩增出条带,其中多态性位点129个,多态性位点百分率为97.93%。Pop Gene结果显示,在物种水平上,供试病原菌的基因多样性指数和Shannon信息指数分别为0.256 3和0.397 8。分子方差分析表明,不同地理种群间的遗传变异占总变异量的7.94%,不同地理种群内的各自然种群间的遗传变异占总变异量的24.46%,自然种群内各分离株的遗传变异占总变异量的67.58%。聚类分析结果表明,在遗传相似系数为0.19时,可将9个病原菌自然种群划分为6个不同的聚类群。【结论】我国枣树干腐病菌(B.dothidea)群体具有丰富的遗传多样性,群体内多样性大于群体间多样性。自然种群内各分离株的遗传变异是我国枣树干腐病菌遗传变异的主要来源。我国枣树干腐病菌的各自然种群之间的遗传亲缘关系与其地理来源无明显相关性。     

Genetic diversity and population genetic structure of pomegranate (Punica granatum L.) in Iran using AFLP markers

Pomegranate (Punica granatum L.) is one of the oldest known edible fruits. It is native to Iran and spread from Iran to other areas. In this study amplified fragment length polymorphism (AFLP) was used to detect intra- and inter-population genetic diversity of pomegranate. A group of 67 accessions belonged to 4 populations from Iran was studied using eight primer combinations. A total of 221 scorable bands were amplified, of which, 118 (54.13%) were polymorphic. Resolving power (Rp) ranged from 5.70 to 9.21, and the average of polymorphism information content (PIC) per primer pair was 0.40. According to Nei's gene diversity and allelic statistics, Isfahan population had a highest genetic diversity (H = 0.3646, I = 0.5327, N_e = 1.6467). Coefficient of gene differentiation between populations (GST) was 0.124, indicated that mainly proportion of genetic variation (87.6%), was within populations and the remaining (12.4%) of the variation was among populations that, also supported by analysis of molecular variance (AMOVA). The gene flow (Nm) varied from 0.969 to 10.404 between pair-wise populations and was 3.504 among all of the populations. The Jaccard similarity coefficient between individuals ranged from 0.26 to 0.88. The UPGMA dendrogram clustered all 67 accessions into 6 groups. In some cases accessions from same region were grouped together but in most cases, there was gene exchange. To study the genetic relationships among populations, a principal coordinate analysis (PCoA) based on Nei's genetic distances was performed. Results of this study showed that AFLP marker can be a useful tool for investigating the genetic diversity of pomegranate genotypes.     

石榴种质资源遗传多样性及亲缘关系的ISSR分析

利用ISSR标记技术对47个石榴品种遗传关系进行了分析。筛选出多态性高的6条ISSR引物,共扩增出120条DNA条带,其中多态性带109条,多态性百分率为90.83%,有效等位基因数(Ne)、Nei’s基因多样(H)、Shan-non信息指数(I)分别为1.294 5±0.309 4、0.189 7±0.161 8、0.309 1±0.219 8,遗传距离(Dg)变异为0.075 0～0.400 0,表明石榴品种间存在比较丰富的遗传多样性。利用UPGMA法构建分子树状图,将47个石榴品种分为5个类群。同时检测到15条特异性条带,可用于供试石榴中的11个品种鉴定的参考性标记。     

山西霍山五角枫不同海拔种群的表型多样性研究

 为了揭示山西五角枫（Acer mono Maxim.）不同海拔种群表型变异程度和变异规律,采用巢式方差分析、主成分分析、相关分析、聚类分析等方法对7个种群200个个体的叶片、果实和种子22个表型性状进行多样性分析。结果表明：五角枫不同种群表型性状存在着丰富的遗传差异,种群间表型分化系数为42.61%,表型变异系数（CV）在7.98% ~ 33.41%之间,7个不同海拔种群的Shannon-Wiener信息指数和Simpson遗传多样性指数分别为2.0164和0.8316,表明五角枫具有较高的表型多样性。主成分分析结果表明,4个主成分对变异的累计贡献率达94.39%,其中果实、叶片贡献率大于种子贡献率。22个表型性状及表型多样性指数与土壤中的钾、磷、pH、速效氮、速效钾、速效磷、土壤有机质、含水量表现出显著或极显著的相关性,说明微生境对其遗传变异的影响。利用群体间欧式距离进行系统聚类分析,可以将7个五角枫种群分为两大类。     

新疆野苹果群体遗传结构和遗传多样性的SRAP分析

 采用SRAP标记,对中国新疆野苹果4个种下居群的群体遗传结构和遗传多样性进行了研究。结果表明：10对SRAP引物总共扩增了209条带,其中206条是多态性带（98.56%）。巩留群体、新源群体、霍城群体和裕民群体分别扩增了180、169、178和165条多态性带,巩留群体的随机交配杂合度（hs = 0.3037 ± 0.0058）最高,其次为霍城群体。UPGMA聚类分析和群体间遗传分化系数显示,巩留群体和新源群体之间,以及霍城群体和裕民群体之间,遗传关系最近,群体间遗传变异最低。新疆野苹果群体内遗传变异高于群体间,占总变异的87.9%,主坐标轴分析显示4个群体是相对独立,其中巩留群体和新源群体,霍城群体和裕民群体之间,有较高的基因交流。所有参数分析表明,巩留群体遗传多样性最丰富,故在制定新疆野苹果原地和异地种质保护计划时应优先考虑巩留群体。     

SSR标记对大颖针禾种群遗传结构的研究

以大颖针禾7个不同地理种群100个样本为研究对象,利用SSR技术从群体水平进行遗传结构的研究。结果表明:大颖针禾遗传多样性丰富,Nei’s基因多样性指数H=0.2244,Shannon多样性指数I=0.3355,这2个指标都在YT种群最高,MSS种群最低;大颖针禾种群的遗传分化系数Fst=0.5475,即在总的遗传变异中有54.75%存在于种群间,种群间遗传距离GD变幅为0.0871~0.2441,地理距离和遗传距离之间无相关性;通过聚类分析,以遗传距离0.14为标准,大颖针禾种群可划分为4个类群。     

Genetic structure of mulberry from different ecotypes revealed by ISSRs in China: An implications for conservation of local mulberry varieties

Mulberry is a perennial and economically important plant that has traditionally been used for feeding the silkworm. Evaluating genetic relationship is important for long-term improvement in mulberry yield, quality and resistance, and for germplasm conservation and identification. Population structure and genetic diversity of 8 mulberry populations from different ecotypes in China were analyzed by ISSR markers. Twelve ISSR primers generated a total of 83 amplification products, of which 50 were polymorphic, revealing 60.24% polymorphism among 66 mulberry local varieties, the mean PIC value was 0.1469. The total heterozygosity (H_T), heterozygosity within population (H_S), diversity between populations (D_ST) were 0.1600, 0.0851 and 0.0749, respectively. The coefficient of population differentiation (G_ST) was 0.4683, indicating that the variations among populations and those within populations contributed 46.8% and 53.2% to the total heterozygosity, respectively. The gene flow (N_m) was 0.5678, suggesting that genetic drift between populations can caused local genetic differentiation and therefore, population divergence. The mean genetic similarity coefficient was 0.8456, genetic similarity coefficient among 8 mulberry populations ranged from 0.8441 to 0.9640, indicating that genetic diversity of different populations existed variation. A dendrogram of all 66 local varieties of mulberry based on the genetic similarity using ISSR markers was generated by UPGMA cluster method. In the dendrogram, most varieties from the same ecotype clustered together.     

中国板栗地方品种重要农艺性状的表型多样性

采用巢式设计方差分析、聚类分析等方法,对中国10个省份90个板栗地方品种叶片表型、坚果表型及品质12个重要农艺性状进行多样性分析。结果表明：（1）板栗12个农艺性状在群体内和群体间差异均达到极显著水平,说明其在群体内和群体间均存在广泛变异;（2）叶片表型性状、坚果表型性状及坚果品质性状的平均变异系数分别为7.7%、4.4%和6.8%,表明坚果表型性状遗传稳定性高于叶片表型及坚果品质性状;（3）群体间表型分化系数V_ST均值为23.42%,远远小于群体内变异（76.58%）,群体内变异是其主要的变异来源;（4）利用群体间最小距离进行聚类分析,将10个板栗群体分为4大类,反映不同地理群体板栗表型多样性存在差异。     

Effects of climatic gradients on genetic differentiation of Caragana on the Ordos Plateau, China

The genus Caragana (Fabr.) in the Ordos Plateau of Inner Mongolia, China, provides a strong opportunity to investigate patterns of genetic differentiation along steep climatic gradients, and to identify the environmental factors most likely to be responsible for driving the radiation. This study used a factorial, multi-model approach to evaluate alternative hypotheses and identify the combination of environmental factors that appear to drive genetic divergence of Caragana in the Ordos Plateau. We had three specific hypotheses. First, we expected that gradients of changing climate would act as resistant factors limiting gene flow, and would provide stronger prediction of genetic differentiation than isolation by distance. Second, we expected that variation in precipitation would be a stronger predictor of genetic differentiation among populations than variation in temperature. Third, we expected that the pattern of phylogenetic differences, in terms of derived versus ancestral states of rachis and leaf shape, would be highly correlated with these gradients of changing precipitation, reflecting adaptive radiation along gradients of changing precipitation driven by reduced gene flow and differential patterns of directional selection. As we expected, variation in precipitation was a much stronger predictor of genetic differentiation than were other climatic variables or isolation by distance. The pattern of phylogenetic differentiation among Caragana species is also closely associated with gradients of changing patterns of precipitation, suggesting that differential precipitation plays a major role in driving the genetic differentiation and adaptive radiation of the Caragana genus in the region of the Ordos Plateau.     

Genetic structure of Buxus sinica var. parvifolia, a rare and endangered plant

Buxus sinica var. parvifolia, a rare and endangered tree species in some semitropics alpine areas of China, plays an important role in the maintenance of the landscape and ecosystem. In this study, RAPD and ISSR markers were used to investigate the genetic diversity and structure of five natural populations and one tamed population of B. sinica var. parvifolia. 21 RAPD primers amplified 209 bands with 167 (79.90%) polymorphic and 21 ISSR primers amplified 518 bands with 467 (90.15%) polymorphic. The genetic diversity, estimated by Shannon’ index, was 0.4343 (by RAPDs) and 0.3661 (by ISSRs). Both RAPD and ISSR analyses revealed a high level of genetic diversity in natural populations of B. sinica var. parvifolia. Furthermore, analysis of molecular variance (AMOVA) was used to apportion the variation within and between populations. The proportion of variation attributable to within-population differences was very high (69.2% by RAPDs; 84.51% by ISSRs). Moderate differentiation was detected among populations using RAPDs (30.80%), while only a small amount of variation (15.49%) was detected among populations using ISSRs. We suggest that the present genetic structure is due to high levels of environmental variability and gene flow, which still need further study to confirm. Conservation measures are suggested, including in situ and ex situ strategies, based on the observed population genetic information.