分子标记技术及其在林木遗传改良研究中的应用

分子标记是继形态标记、细胞标记和生化标记之后发展起来的一种新的较为理想的遗传标记形式,近年来发展非常迅速.本文对DNA限制性片段长度多态性(RFLP)及随机扩增多态性DNA(RAPD)遗传标记技术的基本原理与特点进行了简要介绍.全面阐述了DNA分子标记技术在林木遗传连锁图谱构建、林木遗传资源研究、数量性状位点定位与分子标记辅助育种、目的基因追踪等研究方面的应用及前景.     

RAPD标记在林木遗传育种研究中的应用进展

RAPD技术是一种随机扩增多态性DNA的方法，该技术操作简单、快捷、经济，可从分子水平提供直接的遗传证据。文章阐述了RAPD技术在林木遗传育种研究中4个方面的应用进展，即遗传图谱构建、品种鉴别及亲缘关系分析、遗传多样性分析和标记辅助选择育种。同时展望了RAPD技术的应用前景。     

林木遗传图谱中的遗传标记

1953年 ,J.D.Watson和 F.H.C.Crick提出了 DNA分子结构的双螺旋模型 ,圆满地解释了 DNA就是基因的载体 ,标志着分子遗传学时代的到来 ,现代基因概念的发展使直接利用 DNA分子中核苷酸序列的变异作为遗传标记成为可能。分子标记 ,即以 DNA多态性为基础的遗传标记 ,使分子遗传图谱构建成为可能 ,而分子遗传图谱是进行基因组系统研究的基础。本文将阐述遗传标记的历史发展过程 ,着重讨论目前应用于林木遗传图谱中的几种分子标记及林木遗传图谱的构建情况。1　遗传标记技术的发展遗传标记是基因型易于识别的表现形式。在遗传学实验中通…     

林木分子标记研究及其在育种中的应用

林木分子标记研究主要包括林木遗传连锁图谱构建、比较基因组研究、数量性状位点定位、标记辅助选择、系统演化及群体遗传变异和多样性等内容。迄今已有近 2 0个树种构建了基因组遗传连锁图谱 ,少数树种进行了目标性状位点定位研究 ,定位了为数不多的与分子标记连锁的数量性状位点。林木分子标记已在育种策略制定、辅助选择育种、基因型鉴别 ,以及目的基因的分离和克隆等分子育种研究中广泛应用。     

分子标记在林业辅助选择育种中的应用

本文主要阐述分子标记在林木辅助选择育种中的应用。利用多种分子标记(RAPD,RFLP,AFLP,STS,SSR,STR等),可以在林木早期生长阶段对一些性状进行鉴别, 构建单种分子标记遗传连锁图谱或几种分子标记共存的混合连锁图谱和对控制数量性状的基因进行定位, 对林木群体遗传结构、遗传变异、遗传分化和基因流动进行研究, 在基因工程中, 能够追踪目的基因行为和对控制质量性状的基因进行鉴别, 对单株进行指纹图谱, 对种子质量进行监测和对品系、品种和无性系进行鉴定。     

马尾松实生种子园F1代的RAPD分子鉴别

为了筛选出鉴定马尾松优良杂种F1代的RAPD特征标记,从DNA水平上区分杂交子代,以从23个马尾松实生种子园F1子代嫩叶中抽提的DNA作为试验材料,采用RAPD分子标记技术检验DNA序列的多态性。从99条引物中筛选出5条适合马尾松F1代RAPD扩增且具有多态性的引物S1026、S1110、S1040、S1180、S1172。利用这5条引物,采用RAPD分子标记技术,对23个F1子代进行了标记基因型的研究,得到了27个标记位点,确立了各样品的标记基因型,并在此基础上进行了马尾松子代的分子分类研究。     

现代遗传鉴别方法在林木种苗分析中的应用

现代遗传鉴别方法在林木种苗分析中的应用喻虹（贵州省林业种苗站）关键词遗传鉴别；种苗；应用遗传鉴别已广泛应用于生物学的许多领域，如医学、农学甚至法医学。在基因水平上的林木种子、苗木遗传鉴别对于林木种苗工作者来说是全新的概念和内容，它为种苗分析和鉴别提供...     

银杏16个主要栽培品种的分子鉴别

以16个银杏栽培品种的单倍体胚乳DNA为材料,用筛选出了高效引物进行RAPD分析,确定了各品种的标记基因型.在此基础上,可利用单倍体种子胚乳或二倍体叶片等材料实现对银杏无性系品种的有效分子鉴别,为银杏的良种鉴别、保护和登录提供了科学依据.     

植物种或品种鉴定的展望

植物种或品种的鉴定主要使用4种遗传标记，即形态学标记、细胞学标记、生化标记和DNA标记。由于形态学标记、细胞学标记、生化标记的局限性，往往无法对近缘种或品种的鉴别。该文总结和分析4种遗传标记特点，认为随着分子生物学的发展，DNA分子标记将成为近缘种或品种鉴别的重要手段。     

林木全基因组选择研究现状和应用

全基因组选择（GS）是利用覆盖全基因组的高密度遗传标记对复杂数量性状进行预测的育种方法。在林木种苗阶段根据基因组估计育种值（GEBV）可以利用GS进行个体选择,相比常规育种能增强遗传增益、加快选育进程。该方法无需定位与性状相关的数量性状位点（QTL）,相比分子标记辅助育种能极大地提高对微效位点的捕获功效,是具有巨大潜力的林木育种策略。文中系统介绍了GS的概念和优势,及其在林木中的研究现状和应用。我国林木GS研究处于初期阶段,可优先在常规育种较成熟的树种中开展研究,建立林木GS程序为其他树种提供范式。该综述有助于系统了解全基因组选择育种策略和研究进展,并为全基因组选择在林木育种中的应用提供理论和技术信息。     

分子标记辅助选择在林木育种中的应用

历史上,数量遗传学被认为是指导林木育种的唯一有效工具,这有两个方面的原因：第一,在林木上具有重要经济价值的性状,如树干材积生长、木材纤维长度及适应性等,均是以数量方式遗传的性状,并且控制这些性状的每一个过程是假设受微效多基因所控制的;第二,林木具有很长的世代间隔,很高的遗传杂合性和很高的遗传负荷,这些特性限制了一些经典的遗传材料,如近交系,突变体及特异类型的产生。然而,传统的数量遗传学方法用于指导林木育种的实践并不是完美无缺的。林木个体高大,占地面积大,且大多栽植在非农用耕地上,这样的环境异质性在很大程度上影响性状遗传力的提高,有些林木树种人工杂交比较困难,很难获得足够大的家系,从而产生不平衡的交配设计。Ｎａｍｋｏｏｎｇ 和Ｒｏｂｅｒｄｓ（１９７６） 认为,不平衡的交配设计很难获得准确的遗传参数估计。到目前为止,大多数成功的林木育种方案往往都是基于对表型的简单选择。这种表型选择不能利用林木固有的非加性效应,以及对异质环境的反应潜能,因而育种效果是极为有限的。分子标记技术为现代数量遗传学的发展提供了新的方向。通过利用中性标记与影响数量性状的位点（ＱＴＬ） 之间的连锁关系,人们已经提出了一套统计方法用来鉴定重要的Ｑ     

Effects of seed traits on the success of direct seeding for restoring southern Thailand’s lowland evergreen forest ecosystem

The success of direct seeding, as a low-cost approach to forest restoration, varies with tree species and seed characteristics. A system to predict which tree species are likely to be suitable for direct seeding would therefore be useful for improving forest restoration projects. Therefore, this study aimed to determine the effects of seed traits on the success of direct seeding to restore tropical forest in southern Thailand. Seeds of 19 indigenous lowland tropical forest tree species were collected, from both the east and west sides of the Thailand peninsular and the following parameters measured: seed size, shape, coat thickness and moisture content. Field trials were established to determine seed germination rates and to calculate a “direct seeding suitability score” for each species, which combined seedling establishment and growth rates. Seed size, shape and moisture content were associated with germination percentage. Species with higher seedling survival tended to have large or intermediate-sized seeds, round or oval seeds and seeds with low or medium moisture content. Only seed coat thickness was significantly correlated with the suitability score (r = 0.65, p < 0.01). Seed coat thickness >0.4 mm coincided with higher rank suitability score. These conditions successfully predicted the success or failure of direct seeding for 15 out of 19 species tested. Eight tree species are recommended as suitable for restoring lowland evergreen forest ecosystems in southern Thailand, by direct seeding.     

河北省林木种苗质量监督检验现状及发展对策

国外在林木种苗质量管理工作中规范化程度高,我国近年来林木种苗质量监督检验工作成效明显,各省质检状况明显改观,为河北省提供了借鉴。结合河北省林木种苗质量监督检验工作现状和存在的问题,提出了河北省林木种苗质量监督检验发展思路及对策。并提出提升林木种苗质量监督检验能力、理顺投资渠道、改善基础条件、推进规范化法制化建设四项对策,以期河北省的林木种苗质量监督检验事业又好又快发展,实现依法治种的目的。     

High seedling recruitment of indigenous tree species in forest plantations in Kakamega Forest,western Kenya

Tree plantations are often used to compensate for the destruction and conversion of natural forests in the tropics. An important question is whether these plantations allow for the regeneration of indigenous tree species and are expected to transform into more natural forests in the future. To evaluate the potential of differently managed forest types for seedling recruitment of indigenous tree species we studied structural characteristics as well as tree and seedling communities in stands of natural forest, different types of tree plantations and secondary forest in Kakamega Forest, western Kenya. Forest types differed considerably in structural characteristics and tree composition with stands of natural forest significantly differing from all other forest types in vertical foliage height diversity and number of late-successional tree species. By contrast, total seedling species richness and number did not differ among the forest types. Yet, number of seedlings of late-successional species decreased from natural forest and plantations of a mixture of indigenous tree species towards monocultures and secondary forests while number of seedlings of early-successional species increased in the same order. A joint Principal Component Analysis (PCA) corroborated higher similarity among seedling communities than among tree communities. Our results indicate a convergence of recruiting seedling communities in different forest management types suggesting that tree plantations might buffer forest loss to a certain extent and may have the potential to develop into more natural forest over time.     

Soil seed banks in four 22-year-old plantations in South China: Implications for restoration

To better understand the potentials of the soil seed banks in facilitating succession towards a more natural forest of native tree species, we quantified the size and composition of the soil seed banks in established plantations in South China. The seed banks were from four typical 22-year-old plantations, i.e., legume, mixed-conifer, mixed-native, and Eucalyptus overstory species. Species diversity in the seed banks was low, and the vegetation species differed from those found in the seed bank in each plantation. A total of 1211 seedlings belonging to eight species emerged in a seedling germination assay, among which Cyrtococcum patens was most abundant. All species detected were shrubs and herbs, and no viable indigenous tree seeds were found in soil samples. Size and species composition of the seed banks might be related to the overstory species compositions of the established plantations. The seed bank density in soils was highest in the mixed-conifer plantation followed by Eucalyptus, mixed-native, and legume plantations. Species richness among the seed banks of plantations was ranked as follows: Eucalyptus > mixed-conifer > mixed-native = legume. The results indicated that the soil seed banks of the current plantations are ineffective in regenerating the former communities after human disturbances. Particularly, the absence of indigenous tree species seeds in the seed banks would limit regeneration and probably contribute to arrested succession at the pioneer community stage. It would appear from these data that the soil seed banks under the current plantations should not be considered as a useful tool leading the succession to more natural stages. Introduction of target indigenous species by artificial seeding or seedling planting should be considered to accelerate forest regeneration.     

张掖市北部荒漠区文冠果大田播种育苗试验

文冠果是我国北方新型的生物质能源树种,也是优良的防沙治沙树种和退耕还林树种。通过对文冠果苗圃地选择、种子处理、苗期管理等创新技术的阐述,对文冠果在不同播种方式下的发芽率、出苗率、生长量以及后期管理进行对比观察,从种子处理、播种及播种后管理等主要育苗技术环节入手,初步总结和掌握了文冠果大田引种育苗技术,为文冠果在荒漠区大...     

SSR分子标记及在林木基因组中的应用

主要介绍了SSR分子标记的原理、技术优点、实验技术的流程及在林木基因组中的应用,并展望SSR分子标记将会应用到衰退树种优良基因型的鉴定,从而应用于育种的研究和优良基因型的鉴定与保存等。     

林木种苗工程建设的重大贡献和监管保障

林木种苗是造林绿化的物质基础,是建设绿色湖南的前提.为了加速湖南省林木种苗良种化进程,针对林木种苗工作在现代林业建设中的重大作用、加强种苗社会化服务体系建设、大力推进林木种苗全过程的执法检查和行业监管作了全面系统的论述.     

Germination and early seedling growth of Pinus densata Mast. provenances

We studied seed germination and early seedling growth of Pinus densata to explore the range of variability within the species and to inform afforestation practices.Phenotypes were evaluated at a forest tree nursery under conditions that support Pinus yunnanensis, one of the presumed parental species of P. densata. Seeds were collected from 20 open-pollinated trees within each of eight autochthonous populations representing the natural distribution of P. densata in China to assess variation in germination traits and early seedling growth, and to examine the relationships among these traits. Results showed that seeds from all populations germinated and seedlings established successfully. There were significant differences among populations in 13 of 14 traits evaluated. Seed germination and early seedling growth were strongly related to seed size and seed weight. Bigger seeds germinated earlier and faster than small seeds, and seedling size was positively correlated with seed size. Some germination traits were strongly and significantly correlated with climatic variables associated with the provenance of the studied populations. Based on these observations, we conclude there were large, significant, and biologically important differences among P. densata populations in seed germination and seedling growth traits. The observed variability probably reflects a high degree of adaptive differentiation among populations that is likely to be relevant for future afforestation.