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1.
广东韶关马尾松种子园遗传多样性分析   总被引：1，自引：0，他引：1  
从210个随机引物中筛选出的16个引物,共检测到118条带,其中多态性带95个,总多态位点比率为80.37%,充分说明了马尾松无性系间遗传背景的复杂性和多样性。采用Nei指数计算的建园无性系马尾松有效等位基因数平均值为1.3447,总基因多样性为0.2445,遗传多样度(h)平均值为0.2445,Shannon′s信息指数(I)平均值为0.3558,与一些松柏纲植物的RAPD数据资料相比,马尾松的遗传多样性处于较高水平,显示出该无性系马尾松种子园内各马尾松的遗传基础较宽,具备营建出遗传品质好、遗传多样性高、稳定性好的马尾松人工造林的能力,能满足林木育种的需要。  相似文献   

2.
以林口青山红松无性系种子园216个单株生健康嫩叶为试验材料,利用ISSR-PCR分子标记技术分析其遗传多样性的试验结果表明:从100条引物中共筛选出11条具有多态性的ISSR引物,经ISSR-PCR扩增后共获得102个位点,多态性谱带102条,多态位点比率为100%,单株有效等位基因数变动范围为1.0046~2.000,群体总基因多样性指数为0.3333,Shannon多样性指数为0.0164~0.6931,期望杂合度为0.0046~0.5000,红松种子园单株具有丰富的遗传多样性。  相似文献   

3.
Gene flow from outside pollen sources reduces the expected genetic gain of seed orchards, and has been quantified by genotyping seed samples from crop years to determine the proportion of seed sired by outside sources. Random bulk seed sampling and microsatellite genotyping allows for fast, unbiased identification of orchard contamination rates. Bulk seed sampling has been employed in multiple studies of seed orchard gene flow, but a method of determining precision of gene flow estimates from this sampling method has yet to be described. In this study, we used jackknife resampling to generate random samples of migrant and within-population genotypes obtained from an empirical sample of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) genotypes of five microsatellite loci. We generated samples of 50, 100, 150, 200, and 250 genotyped individuals from a sample of 400 seeds, with genotypes corresponding to low (6%), moderate (14%), or high (56%) pollen contamination levels. The mean gene flow estimate and confidence interval were calculated for each sample size and gene flow scenario to determine the precision of gene flow estimates obtained from each sample size in each contaminant gene flow scenario. Genotyping 150 individuals was sufficient to produce gene flow estimates with calculated confidence interval values below ± 1%, indicating that 150 genotyped individuals were sufficient for precise gene flow estimation in this population. This resampling method will enable precise and unbiased estimation of gene flow into seed orchards for future monitoring of gene flow, to allow better management of seed orchard genetic resources.  相似文献   

4.
A total 61 clone parents and 320 open-pollination progenies from 8 clone individuals were identified by 12 polymorphic SSR loci.The result showed that the level of genetic diversity in progeny population was the same as in maternal population, progeny population had all alleles detected in maternal population,and there were not obvious surplus phenomenon of homozygotes in progeny population (F= 0.046).The south crown had more strobili than the north crown,however the genetic diversity of the north crown strobili was not substantially reduced.The progeny of neutral trees had the same level of genetic diversity as in the progeny of partial female trees,with the fixation index tended to be zero,which was accorded with Hardy-Weinberg equilibrium.The multilocus outcrossing rate in the seed orchard was 1.097,and there was no significant inbreeding between parents(t_m-t_s= - 0.031).The multilocus outcrossing rate and singlelocus outcrossing rate in the south crown were higher than that in the north crown.The multilocus outcrossing rate of partial female trees was the same as in neutral trees,and the neutral tree had no obvious declining outcrossing rate with reduced proportion of female and male strobilus compared with partial female tree, with the fixation index tended to be zero.The progeny of the second generation clonal seed orchard still had rich genetic diversity,gene exchange among clones was relatively sufficient,and biparental inbreeding was not significant.  相似文献   

5.
The distribution of genetic diversity in a local population of Dothistroma septosporum was determined on a microspatial geographical scale. The study was conducted in a seed orchard of Pinus nigra divided into four plots, each of 0.84 ha in area. Ninety‐two isolates were obtained from needles with red band needle blight symptoms. Molecular variance, Mantel test and autocorrelation spatial analyses were performed with the use of random amplified microsatellites markers to test the null hypothesis of a random distribution of genotypes. The groups of isolates from individual plots demonstrated small differences as regards intrapopulation variation. The mean contribution of polymorphic loci for isolate groups was almost 77%, genetic diversity 0.270, while the Shannon coefficient was 0.389. The Mantel test demonstrated a significant, positive correlation between Huff's genetic distance and geographical distance. Significant spatial genetic structure was detected with autocorrelation coefficients being significant in the first two distance classes up to about 8–12 m.  相似文献   

6.
Moniliophithora roreri, causal agent of cacao frosty pod rot, is considered one of the most devastating pathogens of this crop. In this study, we report the development of and validation of 28 microsatellite loci from an enriched library. From these, ten loci were demonstrated to be polymorphic in an Ecuadorian population composed of 27 isolates. The mean number of alleles per locus was 3.2, and the observed mean and expected heterozygosity were 0.03 and 0.43, respectively. The polymorphic microsatellites described herein may be used to study the genetic diversity as well as to comprehend other aspects of M. roreri population biology.  相似文献   

7.
本文应用4对微卫星分子多态引物,对利用优株嫁接建立的蓝桉(E.globulus)树木园中的118个自由授粉子代的DNA微卫星指纹进行了分析.结果表明:选用的引物具有高度多态性,各个位点扩增得到的平均等位基因数为14.25,树木园中母株的异型杂交率为15%(95%,整体异型杂交率为47.9%,外源花粉污染率为17.6%.由于该树木园的异型杂交率低,其自由授粉的种子应用价值不高,因此应采用大规模人工授粉来制种或选用树木园中异型杂交率高的母株采种.  相似文献   

8.
马尾松二代无性系种子园遗传多样性和交配系统分析   总被引：2，自引：0，他引：2  
运用12对SSR引物,对马尾松二代无性系种子园内61个亲本及其中8个无性系单株的320个子代进行研究。结果显示:子代群体包含亲本群体的所有等位基因,子代与亲本具有同样高的遗传多样性,子代群体的F为0.045,纯合子过剩的现象不明显;树冠北面子代遗传多样性并未因其雌、雄球花量较树冠南面减少而有明显的降低;雌雄均衡和偏雌型植株子代遗传多样性基本一致,以偏雌型植株子代略大,二者F趋于0,子代基本符合哈温平衡。种子园异交率较高,多位点异交率为1.098,子代亲本的近交现象不显著(tm-ts=-0.033);树冠南面多位点与单位点异交率均高于树冠北面;偏雌与雌雄均衡型植株的多位点异交率基本相当,雌雄均衡型植株并未因其雌、雄球花量比例较偏雌型植株减小而呈现异交率明显降低的现象,2种类型植株的近交指数均接近于0。整体而言,马尾松二代种子园子代仍具有丰富的遗传多样性,无性系间基因交流相对充分,子代亲本近交现象不明显。  相似文献   

9.
Baobab (Adansonia digitata L) belonging to Bombacaceae family, is one of the most widely used indigenous priority tree species in sub-Saharan Africa, valued in the cosmetic industry for its seed oil, and powdery fruit pulp for juice making. Baobab has high potential for domestication in southern Africa, therefore understanding its genetic diversity and population structuring is warranted. The study investigated the level of genetic diversity and differentiation of five populations of A. digitata L. sampled from four diverse silvicultural zones in Malawi. Variation at nine microsatellite loci were examined in 150 individual trees. Low mean genetic diversity was expressed through genetic diversity indices: Nei’s genetic diversity (h, 0.18 ± 0.03), Shannon Information Index (I, 0.21 ± 0.07), observed number of alleles (na, 1.47 ± 0.10), effective number of alleles (ne, 1.23 ± 0.04) and percentage polymorphic loci (pp, 48 %). The low genetic variation found is attributed to the population growing in marginal areas of genetic centre of diversity of the species, anthropogenic factors and founder effects. Moderate genetic differentiation was observed among populations (Gst = 0.13) indicating the presence of a large number of common alleles resulting in a homogenisation effect. Clustering of individual trees by genetic similarity coefficients indicated that mainland trees were genetically closer than the trees on Likoma Island. Mantel’s test showed a weak positive insignificant correlation (Z = 0.12; P = 0.64) between genetic distance among populations and actual distance on the ground implying that geneflow was not directly influenced by isolation by distance. The results suggest that seed distribution and tree improvement should recognise the presence of ecotypes and conservation measures should protect all the populations due to existence of private alleles which are of adaptive importance.  相似文献   

10.
Molecular genetic analysis was applied to 162 individuals of 37 half-sib selected families belonging to six provenances of Eucalyptus dunnii Maiden in a provenance/family trial. The individuals were selected by a trait selection index and genetic diversity criteria were later applied for designing seedling seed orchards. Genetic diversity and its distribution, as well as relationships among individuals, were assessed on the basis of nine microsatellite loci and 243 amplified fragment length polymorphism markers. High diversity was found with both kinds of markers. Clear-cut genomic patterns of identification (fingerprinting) were obtained for each individual. Genetic differentiation estimates consistently showed low differentiation among provenances (R(ST1) = 0.069, theta(P) = 0.026 and F(CT) = 0.035) and great differentiation among families (R(ST2) = 0.223, theta(S) = 0.174 and F(SC) = 0.164). A high proportion of the total variation was observed within families (around 80% by both marker analyses), suggesting that orchard design should be based on individual or family selection rather than on provenance selection, and that individual ranking by both trait selection index and molecular genetic diversity criteria should be considered. A selection procedure for a seedling seed orchard design is proposed.  相似文献   

11.
腰果混杂群体的遗传组成分析   总被引：2，自引：0，他引：2  
利用AFLP分子标记技术对54个单株构成的腰果混杂群体的遗传组成进行分析,评估其遗传变异水平,旨在为合理有效利用该资源提供科学理论依据。结果显示,筛选出的8对引物组合共扩增出467条谱带,其中,多态性带为179条。多态性带百分率、观测等位基因数、有效等位基因数、Nei’s基因多样性指数和Shannon信息指数分别为38.33%、1.383 3、1.150 4、0.094 6和0.149 2。遗传距离的变异范围在0.017 1~0.250 5之间,平均为0.103 5。UPGMA聚类结果将54个样株归于4个复合组和2个独立组。  相似文献   

12.
为了探讨银白杨、马氏杨及银白杨×马氏杨杂交子代间的遗传多样性参数及个体聚类关系,利用8对引物对银白杨、马氏杨及银白杨×马氏杨杂交子代4个样本进行了AFLP分析。结果表明,8对引物共扩增出780条扩增谱带,其中多态性条带数为715条,多态性比例为91.65%,平均有效等位基因数为1.5017,Nei’s平均遗传多样性指数为0.3065,Shannon平均信息指数为0.4679。不同杂交子代在E-AAC/M-CAG引物对上均有特异性位点,这些特异位点可用于品种鉴定。聚类研究发现,在相似系数为0.76时,试验样品分成2个AFLP群,其中马氏杨为1个AFLP群,银白杨及2个杂交子代为1个AFLP群;当相似系数为0.78时,银白杨和2个杂交子代的AFLP群又划分为2个亚群,其中杂交子代1和杂交子代2聚合为亚群1,银白杨为亚群2。本研究的结果多态性比例很高,对样品的区分率达到100%,为杨树AFLP分析检测提供了指导借鉴价值。  相似文献   

13.
湿地松抗病种子园的遗传多样性分析   总被引：9，自引：0，他引：9  
本文利用RAPD分子标记从DNA水平上研究了湿地松 (PinuselliottiiEngelm)种子园的遗传多样性和连锁不平衡状况。结果表明 ,有效等位基因数目在各位点间变动范围为 1 0 47～ 1 996 ,平均为 1 4 499;基因多样度范围为 0 0 44 9～ 0 4 99,平均为 0 2 781 ;Shannon信息指数的范围为 0 1 0 95～ 0 6 92 2 ,平均为 0 4 32 7;这3个遗传多样性度量的大小顺序基本相同。 1 0 4个分离位点共有 5 35 6个位点对 ,其中 35 5对在显著性水平为0 0 5下达到显著的连锁不平衡状态。该抗病种子园具有较高的遗传多样性和一定程度的连锁不平衡  相似文献   

14.
Information on population genetic structure and crop genetic diversity is important for genetically improving crop species and conserving threatened species.The PAL gene sequence is part of a multigene family that can be utilized to design DNA marker systems for genetic diversity and population structure investigation.In the current study, genetic diversity and population structure of100 accessions of wild Pistacia species were investigated with 78 PAL markers.A protocol for using PAL sequences as DNA markers was developed.A total of 313 PAL loci were recognized, showing 100% polymorphism for PAL markers.The PAL markers produced relatively more observed and effective alleles in Pistacia falcata and Pistacia atlantica, with a higher Shannon's information index and expected heterozygosity in P.atlantica, Pistacia vera and Pistacia mutica.Pairwise assessment of Nei's genetic distance and genetic identity between populations revealed a close association between geographically isolated populations of Pistacia khinjuk and Pistacia chinensis.The accessions of wild Pistacia species had more genetic relationship among studied groups of species.Analysis of molecular variance indicated 19% amongpopulation variation and 81% within-population variation for the PAL gene based DNA marker.Population structure analysis based on PAL revealed four groups with high genetic admixture among populations.The results establish PAL markers as a functional DNA marker system and provide important genetic information about accessions from wild populations of Pistacia species.  相似文献   

15.
Blakesley  David  Pakkad  Greuk  James  Celia  Torre  Franck  Elliott  Stephen 《New Forests》2004,27(1):89-100
Castanopsis acuminatissima (Bl.) A. DC. is one of a number of framework species which are being planted to restore seasonally dry tropical forests in northern Thailand. This study describes the level of microsatellite variation within and among three populations of this species in three National Parks in northern Thailand: Doi Suthep-Pui, Doi Inthanon and Jae Sawn, using published primers developed for Castanopsis cuspidata var. sieboldii Nakai. The five microsatellite loci employed in this study detected a total of 54 alleles (n = 72). The informativeness of the microsatellite loci varied from six to 18 alleles, with an average of 10.8 alleles found over all loci. The mean observed heterozygosities in the three populations showed no significant deviations from Hardy-Weinberg expectations. The vast majority of genetic diversity was contained within the populations, with no significant differentiation between them (FST = 0.006). Algorithms were designed to capture microsatellite diversity, and the rationale for using microsatellite markers to inform genetic conservation is discussed. The implications for seed collection of C. acuminatissima for forest restoration are also discussed.  相似文献   

16.
Marssonina brunnea is an important pathogen that causes Marssonina leaf spot disease of poplar (MLDP) in various poplar species. Resistance breeding is considered as the main method for preventing this disease and requires information on genetic diversity and population structure. However, molecular markers that may be utilized in the identification of this fungus are limited. This study investigated the distribution of microsatellites in the M. brunnea genome. A total of 15,356 microsatellite markers (excluding mononucleotide repeats) were isolated from 50.1 Mb of genomic sequence. Eight M. brunnea isolates were evaluated in terms of 102 loci, followed by the selection of markers that could be utilized in investigating the population structure of 47 M. brunnea isolates from two populations. Twenty‐four polymorphic microsatellite markers were developed for M. brunnea. The number of alleles per locus ranged from two to eight (average: 3.75). The polymorphism information content (PIC) of these loci ranged from 0.0408 to 0.6492. The average Shannon's information index of these loci in the two populations was 0.3819 and 0.5351, respectively. Using these markers, M. brunnea isolates were mainly divided into two distinct clusters based on the relatedness of the sampling sites. These results indicate that the selected markers could be effectively utilized in investigating the population genetic structure of M. brunnea. This is the first report on microsatellite markers in M. brunnea.  相似文献   

17.
With growing concern about maintenance of genetic variation and conservation of gene resources, the question arises on the extent to which a planted population should be considered a resource able to preserve the gene pool of a species. In this study, levels of genetic diversity were assessed in natural and planted populations of Araucaria angustifolia using AFLPs and nuclear microsatellites, in order to assess the usefulness of planted forests in programs of species’ genetic resource conservation. In general, the genetic structure of the plantations was not strongly differentiated from the natural populations. For microsatellites, gene diversity (H) and allelic richness were significantly higher in plantations, while inbreeding was not different between planted and natural populations. For AFLPs, no significant difference was found between groups in the measures of genetic diversity. In the cluster analysis based on microsatellite data, plantations and natural populations from Santa Catarina State were grouped together, suggesting that plantations preserved genetic information very similar to natural populations. The cluster analysis of populations based on AFLP data differentiated plantations from natural populations. This pattern may be a result of genetic hitchhiking of AFLP fragments with genes under selective pressure due to plantations establishment and management. We suggest that the moderate to high level of genetic diversity retained in A. angustifolia populations after the intense fragmentation of the natural forest has the potential to supply plant material with sufficient genetic diversity for the species conservation through the establishment of planted forests. A sustainable management of the extant forest remnants and forestation/reforestation enterprises should additionally attend to trends revealed in previous studies concerning population structure and gene flow.  相似文献   

18.
利用SSR分子标记技术,对采自新疆额尔齐斯河流域阿尔泰市哈巴河及北屯地区的白杨派3个树种银白杨、银灰杨、欧洲山杨的半同胞家系子代进行遗传多样性分析.结果表明:筛选12对SSR引物在90个样本中共检测到58个等位基因(A)、112种基因型,多态位点百分率是100％,Nei遗传多样性指数(h)平均为0.648 5,Shannon多样性指数平均为1.234.基因分化系数(Fst)为0.337 l,即在总的遗传变异中有33.71％的变异来自于不同树种之间,绝大部分存在于子代个体间.白杨派内种间分化程度较高,种间遗传距离为0.3863～1.869;银灰杨的遗传变异最大,而银白杨的遗传变异最小.  相似文献   

19.
Paternity analyses using microsatellites were conducted in two conifer clonal seed orchards (CSOs). The aim was to study mating patterns and potential dysfunctions such as unbalanced male contribution, and how these factors influence genetic diversity. The effect of unequal male contribution was quantified by the status number (NS), which reflects build up of coancestry in the seed orchard crop due to low number of clones and unequal male contribution. This approach was also used to quantify the effect of clonal differences in germination percentages on effective population sizes. Furthermore the genetic diversity of the Abies alba and Larix kaempferi CSOs was compared to other alternative seed sources via observed heterozygosity and allelic richness.  相似文献   

20.
《林业研究》2020,31(4)
Because there are thousands of peach cultivars,cultivar classification is a critical step before starting a breeding project.Various molecular markers such as simple sequence repeats(SSRs) can be used.In this study,67 polymorphic primers produced 302 bands.Higher values for SI index(1.903) suggested higher genetic variability in the genotype under investigation.Mean values for observed alleles(Na),expected heterozygosity(He),effective alleles(Ne),Nei's information index(h),and polymorphic information content(PIC) were 4.5,0.83,5.45,0.83,and 0.81,respectively.The dendrogram constructed based on Jaccard's similarity coefficients outlined four distinct clusters in the entire germplasm.In addition,an analysis of molecular variance(AMOVA) showed that70.68% of the total variation was due to within-population variation,while 29.32% was due to variation among populations.According to this research,all primers were successfully used for the peach accessions.The EST-SSR markers should be useful in peach breeding programs and other research.  相似文献   

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