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1.
以17个优树自由授粉家系种子和子代一年生苗为试验材料,分析了种子性状和幼苗生长差异,并进行相关分析和主成分分析,以探讨薄壳山核桃不同家系种子性状、变异规律及与子代苗期生长的关系。结果表明:薄壳山核桃家系间种子性状、幼苗生长存在丰富的变异,种子性状变异系数为1.63%~11.85%,幼苗生长的变异系数为4.91%~17.26%,种壳厚、发芽率、茎干重和叶干重因变异程度高,可作为育种和优良单株选择重要性状指标;百粒重与种长、种宽呈极显著正相关,长/宽与种长呈极显著正相关,与种宽呈负相关但不显著,说明其长/宽主要取决于种长。种子的种宽变化很小,种长变化较大,地径与种长呈显著负相关,说明种子过长对植株增粗生长有阻碍作用;通过主成分综合评价,初步筛选出家系1、8、4、3、7、12号和9号表现较优的子代,为薄壳山核桃优良植株选择提供参考。 相似文献
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DNA甲基化对基因表达具有重要的调控作用。本研究采用甲基化敏感扩增多态性技术(MSAP)技术对11个不同湿地松×洪都拉斯加勒比松子代及亲本进行甲基化和表观遗传分析。结果表明内侧胞嘧啶的甲基化为湿加松及亲本DNA甲基化主要模式,其中8个杂交组合内侧胞嘧啶的甲基化相对高于亲本中值,不同组合后代之间在CCGG位点胞嘧啶的甲基化水平上存在差异,但差异不显著。进一步分析表明内侧胞嘧啶甲基化与湿加松生长性状表型值及杂种优势值呈负相关关系,但相关关系不显著;与生长性状特殊配合力呈正相关关系,其中与胸径特殊配合力相关关系显著。本研究为湿加松杂种优势与表观遗传分析提供参考。 相似文献
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杉木亲本自交系及其杂交种DNA甲基化和表观遗传变异 总被引：5，自引：0，他引：5
表观遗传调控包括DNA甲基化、染色质结构修饰和小分子RNA调控等机制可能在杂种优势形成过程中起重要作用.为了了解DNA甲基化对杉木杂交后代杂种优势的影响,本研究利用甲基化敏感随机扩增PCR技术(methylation-sensitive AP-PCR,MS-AP-PCR),选取40对引物组合对杉木亲本自交及其亲本的杂交组合后代群体的基因组DNA进行了扩增和分析.结果表明:杉木基因组的DNA甲基化模式主要以内侧胞嘧啶的甲基化为主:6个正反交组合总的甲基化百分率相对于亲本的自交系而言,甲基化率呈减少的趋势;同一组合正反交组合后代之间在CCGG位点胞嘧啶的甲基化水平上无明显差异;6个杂交组合在CCGG的位点上的甲基化位点数明显低于它们的亲本自交子代.对3种甲基化的表达类型与性状表型值、杂种优势值、配合力进行的相关分析结果表明,检测位点外侧胞嘧啶半甲基化、内侧胞嘧啶甲基化位点变化与杉木树高,胸径和材积性状的杂种优势均成显著负相关,即杉木基因组外侧胞嘧啶半甲基化程度越低、内侧胞嘧啶甲基化位点越少,3个生长性状的杂种优势愈明显;而其他甲基化程度的指标与杂种优势之间的相关均没有达到统计学的显著水平. 相似文献
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用多态位点率和香农指数分析的 飞蝗地理种群遗传多样性 总被引：1，自引：0，他引：1
研究多态位点率和香农指数两种多样性参数所展示的飞蝗不同地理种群的遗传多样性。采用多态位点率和香农指数对飞蝗不同地理种群的RAPD数据进行了遗传多样性分析。飞蝗各种群平均多态位点率为59.17%-77.38%,平均香农指数为4.95-6.09。尽管两参数在不同引物之间存在极显著差异,但各种群的两参数之间的差异都不显著（p<0.05）。将香农指数分解为种群内和种群间两种水平的多样性,种群内多样性都比种群间的要大,平均所占比率分别为66.85%和23.15%,与用其他方法得到的结果类似。多态位点率和香农指数展示出中国飞蝗不同地理种群具较高的遗传多样性。两种多样性性参数分析RAPD数据来展示昆虫遗传多样性是可行的。 相似文献
6.
研究多态位点率和香农指数两种多样性参数所展示的飞蝗不同地理种群的遗传多样性。采用多态位点率和香农指数对飞蝗不同地理种群的RAPD数据进行了遗传多样性分析。飞蝗各种群平均多态位点率为59.17%-77.38%,平均香农指数为4.95-6.09。尽管两参数在不同引物之间存在极显著差异,但各种群的两参数之间的差异都不显著（p<0.05）。将香农指数分解为种群内和种群间两种水平的多样性,种群内多样性都比种群间的要大,平均所占比率分别为66.85%和23.15%,与用其他方法得到的结果类似。多态位点率和香农指数展示出中国飞蝗不同地理种群具较高的遗传多样性。两种多样性性参数分析RAPD数据来展示昆虫遗传多样性是可行的。 相似文献
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利用SRAP分子标记分析了国内外64份不结球白菜种质资源的DNA遗传多样性和遗传分化。21对引物组合共检测出215个位点，其中112个为多态性位点，多态性比率达52.09%，平均每对引物组合产生10.24个位点和5.33个多态性位点。不结球白菜各类型中普通白菜的Nei’s基因多样性指数（0.1410）和遗传丰富度[(190) 88.37%]最高；各生态区域中江淮流域不结球白菜的Nei’s基因多样性指数（0.1451）和遗传丰富度[(185) 86.05%]最高；国内的Nei’s基因多样性指数(0.1293)和遗传丰富度[(188) 87.44%]分别高于国外。遗传变异估算表明，不结球白菜遗传分化系数58.22%，大部分变异存在于种群间；基因流为0.4031，说明群体间基因流动较少，遗传分化程度较高。以遗传相似系数0.872为截值，可把不结球球白菜分为Ⅵ个类群。 相似文献
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不结球白菜(Brassica campestris ssp. chinensis Makino)种质资源SRAP遗传分化分析 总被引：1，自引：0，他引：1
利用SRAP分子标记分析了国内外64份不结球白菜种质资源的DNA遗传多样性和遗传分化。21对引物组合共检测出215个位点,其中112个为多态性位点,多态性比率达52.09%,平均每对引物组合产生10.24个位点和5.33个多态性位点。不结球白菜各类型中普通白菜的Nei’s基因多样性指数（0.1410）和遗传丰富度[(190) 88.37%]最高;各生态区域中江淮流域不结球白菜的Nei’s基因多样性指数（0.1451）和遗传丰富度[(185) 86.05%]最高;国内的Nei’s基因多样性指数(0.1293)和遗传丰富度[(188) 87.44%]分别高于国外。遗传变异估算表明,不结球白菜遗传分化系数58.22%,大部分变异存在于种群间;基因流为0.4031,说明群体间基因流动较少,遗传分化程度较高。以遗传相似系数0.872为截值,可把不结球球白菜分为Ⅵ个类群。 相似文献
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不同种源黄连木遗传多样性研究 总被引：3，自引：0，他引：3
采用RAMP对我国不同地区的180份黄连木材料进行遗传多样性、种群内和种群间的遗传变异进行了研究。结果表明,13对引物组合所产生的115条DNA扩增片段中,有109条具有多态性,多态位点百分率PPB为94.78%;Shannon多样性指数I=0.5541,Nei's多样性指数H=0.38030,物种总基因多样性(Ht)为0.2963;种群内基因多样性(Hs)为0.3803,群体间基因分化系数(Gst)为0.2209,表明22.09%的变异存在于种群间,群体内的变异占总变异的77.91%;基因流(Nm)为1.7633,显示种群间的基因交流顺畅。 相似文献
10.
龙脑香科(Dipterocarpaceae)濒危植物望天树(Parashorea chinensis)目前仅局限分布于热带亚洲北部边缘,目前已受到特别的保护,但有关其遗传特性的研究很少.在本研究中,使用随机扩增多态性DNA(RAPD)技术对望天树7个天然居群进行了遗传多样性和群体遗传结构的研究.望天树7个天然居群(194个个体)用20个随机引物进行了扩增,48.22%的RAPD位点为多态位点,平均每个居群的多态位点百分比为20.84%.居群内的平均基因多样度为0.7870(用Shannon表型多样性指数来测量),整个物种的基因多样度为1.4100,居群内的基因多样度为55.82%,居群间的基因多样度为44.18%.GST平均值为0.4448.AMOVA 分析表明37.67%的遗传变异存在于地区间,11.40% 存在于地区内的居群间,而50.93% 则存在于居群内.结果揭示了望天树低水平的遗传多样性和很强的地区居群分化,这可能是由于望天树在其进化历史上,居群不断的减小及再扩张所引起的居群瓶颈所造成的.相关分析没有检测到居群大小和遗传多样性大小的正相关,而居群间的遗传距离和地理空间距离检测到了显著的正相关.所得结果对该物种保护策略的制定有指导作用. 相似文献
11.
Based on polyacrylamide gel electrophoresis, nine natural populations of Atriplex halimus L., a perennial shrub, collected in different regions of Morocco, were studied for their genetic variation using isoenzyme
polymorphism of the highly active enzyme systems: esterases (EST), acid phosphatases (ACP) and glutamate oxaloacetate transaminase
(GOT). Different allozyme frequencies from 7 different loci were obtained for all populations of this halophyte species. High
levels of genetic diversity were revealed. The mean number of alleles per locus (A = 1.9–2.0), the percentage of polymorphic
loci (p = 71.4–85.7) and the mean expected heterozygosity (He = 0.339–0.385) showed an important variability in all populations. Gene diversity was essentially explained by the within
population component. The between populations differentiation accounted for 8% of the whole diversity (FST, averaged over all loci, is 0.08). The relationships among the 9 populations were inferred from the Nei’s genetic distances.
Four major groups were formed. The northern population ‘Tanger’, forming a unique group, was highly divergent from the other
groups. It appeared that the genetic distance between all groups was related to the geographic distance that separates them.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
Variability for desirable alleles within elite breeding populations is a requirement for long-term genetic improvement. Changes in genetic diversity were evaluated in a recurrent selection programme for enhanced grain yield in oat, Avena sativa L., using coefficient of parentage (rp) and restriction fragment length polymorphism (RFLP) based genetic similarity (S) estimates. Both rp and s increased during seven cycles of recurrent selection, indicating a reduction in the level of genetic diversity within the population. The relationship between genetic diversity and agronomic performance was also examined. Genetic similarity measures were poor predictors of the near-homozygous progeny performance and general and specific combining ability effects for three agronomic traits in the recurrent selection programme. In addition, there was no apparent trend for preferential selection of progeny from either more similar or more diverse parents within a given cycle of selection. The overall reduction in genetic diversity in this population has not affected selection response for grain yield. Variability remaining at important loci or de novo variation are possible explanations for the continued selection progress. 相似文献
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In order to reveal levels and distribution of genetic variation within Oryza rufipogon Griff. of Yunnan, China, where one of the centers of genetic diversity for Asian cultivated rice O. sativa L. is located, allozyme variation encoded by 22 loci was electrophoretically analyzed in 149 individuals of all three existing
populations as well as five from other regions (Guangxi, Hainan and Jiangxi provinces) of China. As compared to the level
of genetic diversity (the mean A = 1.2, P = 24.1%, Ho = 0.045 and He = 0.079) for the populations from other regions, a rather
low genetic diversity (the mean A = 1.1, P = 7.6%, Ho = 0.007 and He = 0.011) was found in Yunnan, which may originate from
marginal nature of these populations, recent reduction of populations and consequent drift. The result suggests that the current
center of genetic diversity for O. rufipogon fail to agree with that for cultivated rice in China. The genetic differentiation for all the eight populations(FST = 0.254) was slightly lower than that for three populations from Yunnan (FST = 0.302), indicating a fairly high genetic differentiation in the region. Finally, a conservation plan for sampling/preserving
fewer populations but more individuals from each population for the species was given, and an appropriate strategy for conserving
the three surviving populations from Yunnan was proposed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
Luciana Rossini Pinto Maria Lucia Carneiro Vieira Cláudio Lopes de Souza Jr Anete Pereira de Souza 《Euphytica》2003,134(3):277-286
BR-105 and BR-106 are important tropical maize populations, which were submitted to a high-intensity reciprocal recurrent
selection, generating the IG-3 and IG-4synthetics. Using 30-microsatellite loci,we measured and compared the genetic diversity
of these populations and their synthetics. The populations did not differ significantly regarding the amount of genetic diversity.
As a consequence of selection, genetic variability losses, in terms of mean number of alleles per locus,proportion of polymorphic
loci, and gene diversity did occur and were greater in the synthetic IG-3 than IG-4. In the synthetics, the number of loci
in adherence to Hardy-Weinberg proportions was superior to that observed in the populations. The Wright's mean fixation index
was higher than the mean value expected for outcrossing species (5%) indicating as light excess of homozygotic individuals
in both populations. The genetic distances confirmed the favourable effects of one cycle of recurrent selection, as the synthetics
became more isolated in comparison to the original populations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
不同人工植被恢复模式对山核桃林地土壤理化性质的影响 总被引：2，自引：1，他引：1
为了探讨山核桃林下不同人工植被恢复模式对山核桃林地土壤养分及山核桃产量的变化规律,对宁国仙霞镇典型山核桃生态严重退化的林地通过人工植被建植5年后的土壤养分进行分析。结果表明：不同植被恢复模式下土壤pH 4.5~6.5;全钾的平均含量0.92 g/kg;全镁的平均含量0.98 g/kg。山核桃林下种植紫穗槐模式、山核桃林下施除草剂模式的含氮量较低;山核桃林下种植白三叶模式的全钙的含量66.25 mg/kg以及含氮量112.68 g/kg最高;山核桃林下种植百喜草模式的含水率17.68%最高,含氮量较高。山核桃林下种植紫穗槐模式样地产量最高,山核桃林下施除草剂模式样地产量最低。经多重比较,不同经营模式山核桃林下,种植紫穗槐模式有效增加山核桃的产量,种植百喜草模式对水分的保持效果最好,土壤pH 5.88对山核桃的生长比较有利。 相似文献
16.
黧蒴栲遗传多样性的AFLP分析 总被引：1，自引：1，他引：0
遗传多样性分析为黧蒴栲优良品种的培育和利用提供技术依据。利用AFLP技术对39个黧蒴栲半同胞家系进行遗传多样性分析,结果显示利用8对引物共扩增出清晰条带761条,其中有多态性的条带有565条,多态率为74.14%,半同胞家系之间遗传多样性较高。黧蒴栲不同优树采集地之间遗传多样性较大,遗传多样性表现出较明显的地域性。各优树采集地内的遗传多样性表现不一致：湖南通道、福建明溪、广东平远优树采集地内遗传变异小;广西永福、融水、平果3地优树采集地内遗传变异较大,存在较大的遗传多样性;广西苍梧优树采集地内遗传变异最大。黧蒴栲出现优良半同胞家系的几率和遗传多样性密切相关,遗传多样性高的出现优良半同胞家系的几率大。出现优良家系的几率与家系所处的地理位置具有相关性,优良率与家系所处的纬度呈高度负相关,与经度为中度负相关。 相似文献
17.
采用覆盖20条染色体的68对多态性引物在120个大豆品种（系）[包括67个中国大豆品种（系）和53个引自美国的品种（系）]进行遗传多样性及亲缘关系分析。结果表明,120份大豆材料具有丰富的遗传多样性（Na=1.9852,Ne=1.4343,H=0.2776,I=0.4361）;中国大豆比美国引进大豆遗传多样性水平高;7个群体遗传多样性由高到低为,黄淮海地区组>引种资源组>热带亚热带地区组>长江流域地区组>北方春大豆组>西南山区组>鲜食大豆组;7个群体间总遗传多样度（Ht）为0.2807,群体内遗传多样度（Hs）为0.2361,群体间遗传分化系数（Gst）为0.1589,基因流（Nm）为2.6468,群体间存在中低度遗传分化,遗传变异主要存在于群体内部,群体间Nm较丰富;以群体和单个品种（系）为单位进行UPGMA聚类的结果基本一致,部分材料相互交错。大豆种质遗传多样性与地理来源具有一定相关性的同时,不同地区间存在丰富的基因交流;黄淮海地区、西南山区、热带亚热带地区和长江流域地区的大豆材料遗传距离较近;引进大豆、北方春大豆和鲜食大豆与其他群体遗传距离较远,可作为拓宽中国栽培大豆遗传背景的物质遗传基础。 相似文献
18.
Paula Menna Barreto Dias Bernadette Julier Jean-Paul Sampoux Philippe Barre Miguel Dall’Agnol 《Euphytica》2008,160(2):189-205
The NPGS-USDA core collection with 85 accessions of red clover, an important forage species, is little described. The goal
of the present study was to evaluate the diversity of a set of accessions from the core collection at the morphological and
molecular level in order to extract some valuable accessions for Brazilian red clover breeding programs. Twenty-one morphological
traits, collected in field and greenhouse in South Brazil, and seven SSR markers were used to describe 57 accessions from
the U.S. core collection and one population cultivated in Southern Brazil. Variation between accessions was large for most
of the 21 morphological traits. A cluster analysis based on the morphological traits revealed five distinct clusters that
separated the populations according to flowering earliness, as already described, but also according to persistency, growth
habit and dry matter productivity. Over seven SSR loci, the number of alleles averaged 11.1 alleles per locus. Genetic diversity
measured with SSR markers was high, with a mean expected heterozygosity of 0.86. An analysis of molecular variance revealed
that the largest proportion of variation (83.6%) resided at the within population level. Although the molecular markers also
separated accessions into five clusters, there was no coincidence between the composition of groups found with morphological
and molecular data. Use of genetic diversity in breeding programs requires to use the most promising populations, to combine
positive traits such as persistency and forage yield, and probably to use within population variation to detect valuable genotypes
that could be used as parents of synthetic varieties. 相似文献