刺葡萄种内遗传多样性研究进展

刺萄萄主要分布在我国长江中下游及以南地区,是中国野生萄萄中果粒最大的一个种,其果实高抗炭疽病和白腐病,在湖南、江西、福建、贵州等省的部分地区一直作为鲜食和酿酒品种栽培利用。刺葡萄种内遗传多样性较为丰富,为了充分挖掘利用刺葡萄资源,提高刺葡萄资源的利用效率,本文从刺葡萄的物候学、花器类型、形态性状、果实理化性状、花粉形态、DNA遗传水平和抗性等方面进行种内多样性的研究和综述,以期为刺葡萄种质资源的保护、鉴定评价和发掘利用奠定基础。     

中国东乡野稻遗传因子转移的研究

本文研究了东乡野生稻群中一个种的表型特征,生态特性,并从数量性状和细胞遗传学的角度研究了东乡野生稻作为父本与不同遗传背景的７个籼型型栽培品种的遗传重组,及优质早籼９０－２的育成,重点探索了该变种的有用基因向栽培稻的转移及育种价值。结果表明,该类型具有育种价值的遗传因子能转移到栽培品种中去,并使栽培品种的一些目标性状得到改良。     

中国葡萄属野生种质资源的研究利用

葡萄属(Vitis L.)约有70余种,原产我国的有31种或变种。在我国,葡萄属植物从海南岛到大兴安岭,从西藏高原到东海之滨均有分布。其分布之广,产量之大,种类之多,特性之丰富,在全世界各国是少有的。自50年代起我国开始重视对葡萄野生种质资源的调查研究,曾收集了一些种或类型。西北农业大学自1978年起对原产我国的葡萄属野生种进行了大量的调查、征集、保存和研究利用。现已从全国10多个省(区)收集保存有19个种和变种,共计100多个株系(单株)。初步建立起我国规模最大的中国葡萄野生种质资源圃。我国葡萄属植物有的种也被国外收集和研究,并认为我国的葡萄属植物中拥有丰富的抗病种质。根据多年的调查研究表明,原产我     

中国东乡野生稻遗传因子转移的研究

本文研究了东乡野生稻群中一个变种的表型特征,生态特性,并从数量性状和细胞遗传学的角度研究了东乡野生稻作为父本与不同遗传背景的７个籼型栽培品种的遗传重组,及优质早籼９０－２的育成,重点探索了该变种的有用基因向栽培稻的转移及育种价值。结果表明,该类型具有育种价值的遗传因子能转移到栽培品种中去,并使栽培品种的一些目标性状得到改良。     

基于SSR标记分析小豆及其近缘植物的遗传关系

本研究利用87对SSR引物分析了80份栽培小豆(Vigna angularis)、22份野生小豆(V.angularis var.nipponensis)以及10份豇豆属(共7个种)近缘植物,旨在比较豇豆属不同种的遗传多样性,并分析种间的遗传关系.结果显示87对SSR引物在112份小豆及其近缘植物资源中共检测到667个等位变异.其中有75个、71个和82个SSR位点分别在栽培小豆、野生小豆和近缘植物中表现为多态.随机抽样分析发现,平均每SSR位点检测到的等位变异数目为近缘植物>野生小豆>栽培小豆,与多态信息含量(PIC)值一致,说明近缘植物及野生小豆中蕴含着丰富的遗传变异,是栽培小豆育种的重要基因来源.聚类分析显示,栽培小豆、野生小豆和近缘植物间的遗传分化比较明显,分别聚为三大类,其中栽培小豆的遗传背景与其生态环境相对应;近缘植物又可以分为三个亚类,亚类间的遗传距离与其亲缘关系相对应.本研究结果也说明利用SSR标记辅助豇豆属的种间分类是可行的.     

抗风桐(Pisonia grandis)的生态生物学特征

对收集于广西桂林的17份野生毛葡萄种质和24份栽培葡萄种质,分别使用12条ISSR和12条SCoT引物进行了遗传多样性和亲缘关系检测。结果表明：两种分子标记均能产生较丰富的多态性片段,可有效应用于葡萄的遗传多样性检测,但在聚类分析结果上表现出一定的差异性,SCoT分子标记能更好地区分野生种质和栽培品种,说明SCoT分子标记在葡萄遗传多样性检测和系统进化研究上可能更有优势。从SCoT聚类结果上看,广西植物研究所收集的3个野生毛葡萄种质zws1、zws2和zws3相对其它野生种质而言,更偏向于与栽培种质聚为一类,说明这一类野生毛葡萄可能是这些栽培品种的原始亲本来源之一。不同的野生种质聚为多个类群,并表现出明显的地域特性,但遗传距离相对较远,说明桂林野生毛葡萄资源具有丰富的遗传变异。栽培品种没有明显的聚类特点,可能因为所选用的栽培品种的地域代表性并不是很强,也可能是因为栽培品种在不断的人工杂交选育过程中,遗传背景趋向一致,遗传多样性降低。该研究证明SCoT分子标记在葡萄遗传多样性研究上具有一定的优势。该研究结果为桂林毛葡萄资源的保护、利用和品种选育提供了理论依据,也为葡萄的系统进化研究提供了参考。     

油茶栽培历史与长江流域油茶遗传资源

普通油茶(Camellia oleifera)是我国第一大木本油料作物。普通油茶作为油料作物的栽培历史, 现存确切记载不到1,000年, 长江流域可能是最早栽培油茶的地区之一。普通油茶的野生近缘种是油茶育种宝贵的遗传资源。普通油茶属于山茶科山茶属(Camellia)油茶组(Sect. Oleifera), 其野生近缘种应包括山茶属油茶组和短柱茶组(Sect. Paracamellia)的物种, 但油茶组和短柱茶组的划分仍有争议, 物种间的系统发育关系仍不清楚。油茶组和短柱茶组是山茶属中多倍体出现频率最高的类群, 而且存在突出的种内多倍性现象, 人工选择和种间杂交可能在其中起到促进作用。长江流域是普通油茶的主产区, 也是最主要的野生普通油茶分布区, 拥有丰富的野生普通油茶遗传资源。本研究统计了山茶属油茶组和短柱茶组物种的分布地, 并与野生普通油茶的潜在分布区进行了比较。分析结果显示, 长江流域与珠江流域的分水岭——南岭、苗岭及附近地区是油茶组和短柱茶组物种多样性最高的地区, 同时也是野生普通油茶潜在的高适生区, 可能是普通油茶及其野生近缘种潜在的种间杂交带。物种多样性从南向北呈下降趋势, 可能反映了从南向北的扩散方向。普通油茶及其野生近缘种间的潜在杂交带可能蕴含着丰富的遗传多样性, 为选择育种提供了天然的育种场, 应对这些地区优先开展研究和保护, 挖掘与利用有重要经济价值的遗传资源。     

稻种遗传资源多样性的开发利用及保护

由于近年来栽培稻众多改良品种的育成和大面积推广,使之在很大程度上取代了地方品种,造成栽培稻基因源的大量基因流失,导致栽培稻品种的遗传基础越来越狭窄以至不能承受新病、虫害和不利环境的袭击。同时,由于人们长期施用杀虫剂、灭菌剂和除草剂等化学农药,严重地恶化了农业生态环境。要改变这种恶性循环的局面,开发和利用稻种的遗传资源,以丰富栽培稻品种的遗传基础是非常必要的。稻种基因源包括了亚洲栽培稻、非洲栽培稻、杂草稻、稻属的野生物种以及稻族内的近缘属种,它们是栽培稻品种进一步改良所不可缺少的遗传资源。但是,由于农业生产模式的改变,社会经济和工业化水平的迅速发展和提高,稻种基因源的多样性受到了严重的影响和威胁。一些野生稻种的居群已经迅速地缩小甚至从原产地消失。因此,对稻种基因源及其多样性进行及时有效的保护,并对其进行合理的开发和利用,是保证栽培稻进一步改良和持久生产的最有效方法。     

中国野生葡萄遗传多样性的ＲＡＰＤ分析

发起源于中国的１８个野生葡萄种（７３个株系）、１个欧美杂交种、７个欧洲葡萄品种、１上砧木品种和河岸葡萄（Vitis riparia L.)一个品系为试材,利用ＲＡＰＤ技术研究了中国野生葡萄的遗传多样性,从２８０个随机引物中筛选出２０个多态性好的引物扩增供试材料,产生了１９１条多态性,应用ＵＰＧＭＡ聚类方法（类平均法）,获得了８３份材料的遗传距离矩阵及聚类分析树系图,且聚为２２类１２组。河岸葡萄、欧洲葡萄（V.vinifera L.)及欧美杂种与中国野葡萄亲缘关系较远。在中国野葡萄中,菱叶葡萄（V.hancockii Hance)与其他种的亲缘关系最远,秦岭葡萄（V.qinlingensis P.C.He)次之,并可将中国野葡萄资源的１８个种、变种和类型分为１０组,种内不同花型株系间的遗传变异较大。     

野生大麦与栽培大麦醇溶蛋白遗传多样性比较

利用A-PAGE(acid-polyacrylamide gel electrophoresis)法对采自以色列的野生大麦的一个野生自然群体的15个系和来自世界不同国家的14份栽培大麦品种醇溶蛋白的遗传多样性进行了分析.结果表明:在所有的29份供试材料中,共发现52条相对迁移率不同的谱带.52条谱带的出现频率为3.44%～93.1%,多样性指数为0.066～0.368;以中国春醇溶蛋白为标准,ω区大麦醇溶蛋白的谱带数最多,其次是β区;野生大麦Shannon多样性指数依次为β区>ω区>α区>γ区,而栽培大麦Shannon多样性指数依次为ω区β>区>γ区>a区;野生大麦自然群体和栽培大麦品种间的遗传相似系数变幅相当,且聚类分析结果显示,野生大麦自然群体和来自全球不同区域栽培大麦品种间的醇溶蛋白遗传多样性同样丰富.以上结果说明,野生大麦中保存了较栽培大麦更为丰富的基因资源,今后栽培大麦的品质改良应该重视野生大麦资源的合理利用.     

On a method of estimating the genetic correlation between characters measured in different experimental units

Summary Yamada's method of estimating genetic co-variances between traits measured in different experimental units is discussed. It is shown that if the data are unbalanced, this method gives biased estimates of genetic covariances unless the traits have identical genetic and residual variances. An alternative unbiased procedure is suggested.     

植物种质群体遗传结构改变的测度

本文旨在探讨植物种质资源保存中由于人为和自然缘故导致遗传结构改变的评价指标和评价方法.在介绍植物种质资源保存研究一些基本概念的基础上,归纳了测度种质库(收集品)遗传潜势的6种遗传多样性统计指标,包括同一变异层次的类型数、类型分布均衡度、遗传相似性与遗传距离、遗传方差与遗传变异系数、多元变异指数以及亲本系数.指出若无遗传丰富度相伴,单有遗传离散度并未提供遗传多样性的完整测度.探讨了人为条件导致植物种质资源遗传结构改变的遗传流失、环境胁迫所致植物种质资源遗传结构改变的遗传脆弱性和种子扩繁所引发的植物种质资源遗传结构改变的遗传漂变和遗传漂移等的统计指标.文末给出了自花授粉植物和异花授粉植物群体适宜样本容量研究的个例.     

Genetic differentiation among local populations of Asian elephant

Electrohoretically detectable enetic variation for 29 kinds of blood protein encoded by 33 loci was analyzed for 78 Asian eletants (Elephas maximus) which were collected from its four local populations: Sri Lanka, Souti India, Thailand and Nepal. Elehants in Sri Lanka are classified into the subspecies E.m. maximus, and those from the other tlree localities into the subspecies E. m. indicus. Six variable loci were detected, and one of them, the tetrazolium oxidase locus, was observed to show a complete allele substitution between the subspecies. Average heterozgosity within local populations were in a range of 0.0152 ? 0.0303. Whereas the Nei's genetic distance among three local populations of the subspecies indicus were 0.0013 ? 0.0031, the distance between the subspecies indicus and maximus were 0.0328 ? 0.0370, indicating that the two subspecies were well differentiated genetically.     

Remarkable genetic divergence of Gymnodiptychus dybowskii between south and north of Tianshan Mountain in northwest China

Gymnodiptychus dybowskii is endemic to Xinjiang, China and has been locally listed as protected animals. To investigate its genetic diversity and structure, specimens were collected from six localities in Yili River system and Kaidu River. Fragments of 1092bp Cyt b gene were sequenced for 116 individuals. A total of 21 haplotypes were found in all samples, and no haplotype was shared between Yili River system and Kaidu River population. Sequence comparisons revealed 123 variable sites, with eight singleton sites and 115 parsimony informative sites. For all the populations examined, the haplotype diversity (h) was 0.8298 ± 0.0226, nucleotide diversity (π) was 0.2521 ± 0.1202, and average number of pairwise nucleotide differences (k) was 275.3369 ± 118.5660. AMOVA analysis showed that the differences were significant for total populations except for Yili River system populations. The pairwise F_st values revealed same conclusion with AMOVA analysis: Kaidu River population was divergent from Yili River system populations. The genetic distance between two groups was 0.108 and the divergence time was estimated at 5.4–6.6 Ma, the uplift of Tianshan Mountain might have separated them and resulted in the genetic differentiation. The neutrality test and mismatch analysis indicated that both two groups of G. dybowskii had went through population expansion, the expansion time of Yili River system and Kaidu River population was estimated at 0.5859–0.7146 Ma and 0.5151–0.6282 Ma, respectively. The climate changes of Qinghai-Tibetan Plateau might have influenced the demographic history of G. dybowskii.     

Genetic polymorphism in varietal identification and genetic improvement

Summary New sources of genetic polymorphisms promise significant additions to the number of useful genetic markers in agricultural plants and animals, and prompt this review of potential applications of polymorphic genetic markers in plant and animal breeding. Two major areas of application can be distinguished. The first is based on the utilization of genetic markers to determine genetic relationships. These applications include varietal identification, protection of breeder's rights, and parentage determination. The second area of application is based on the use of genetic markers to identify and map loci affecting quantitative traits, and to monitor these loci during introgression or selection programs. A variety of breeding applications based on these possibilities can be envisaged for Selfers, particularly for those species having a relatively small genome size. These applications include: (i) screening genetic resources for useful quantitative trait alleles, and introgression of chromosome segments containing these alleles from resource strain to commercial variety; (ii) development of improved pure lines out of a cross between two existing commercial varieties; and (iii) development of crosses showing increased hybrid vigor. Breeding applications in segregating populations are more limited, particularly in species with a relatively large genome size. Potential applications, however, include: (i) preliminary selection of young males in dairy cattle on the basis of evaluated chromosomes of their proven sire; (ii) genetic analysis of resource strains characterized by high values for a particular quantitative trait, and introgression of chromosome segments carrying alleles contributing to the high values from resource strain to recipient strain.Contribution from The Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, No. 767-E, 1983 Series     

Loss of genetic diversity from heterogeneous self-pollinating genebank accessions

Genebank seed accessions of predominantly self-pollinating species may be stored either as bulked (mixed) seed lines or as pure line cultivars. If seed lines are bulked in storage then when considered over several regeneration cycles, loss of genetic diversity within heterogeneous self pollinating genebank accessions is shown to be severe. This within-accession loss of diversity represents opportunities foregone through the random loss of individual genotypes. Amongst working collections, the utility and repeatability of genebank accessions is paramount in the justification of the germ plasm resource. Therefore, the only practical solution to the management of predominantly self-pollinating species is to preserve individual accessions as pure lines.     

Genetic traits

Recognizing that all traits are the result of an interaction between genes and environment, I offer a set of criteria for nevertheless making sense of our practice of singling out certain traits as genetic ones, in effect making a distinction between causes and mere conditions. The central criterion is that a trait is genetic if it is genetic differences that make the differences in that trait variable in a given population. A second criterion requires that genetic traits be individuated in a way that matches what some genetic factors cause specifically. Clarifying our causal and classificatory language here can help us to avoid confusions of both theoretical and practical significance.     

Genetic diversity and structure of natural Pinus tabulaeformis populations in North China using amplified fragment length polymorphism (AFLP)

Chinese pine (Pinus tabulaeformis carr.), endemic to China, is a conifer species with extensive and fragmented distribution in North China. In this study, the genetic diversity and structure of 20 natural populations of this species were investigated using amplified fragment length polymorphism (AFLP) markers. A total of 445 fragments were revealed with 8 pairs of primers, 379 (85.17%) of which were polymorphic. A moderate level of genetic diversity was detected at the species level (Shannon's information index I = 0.356, Nei's gene diversity H_E = 0.271) and at the population level (I = 0.219, H_E = 0.206). Most of genetic variation was within populations while a considerable level of genetic differentiation was detected (G_ST = 0.352, Ф_ST = 0.304). The high differentiation could be attributed to the complex and fragmented habitats, and a limited gene flow among populations (N_m = 0.572). The Mantel test indicated that there was significant correlation (r = 0.455, P < 0.001) between Nei's genetic distance and geographical distance among all the populations. The results suggested that proper countermeasures should be taken to prevent the habitat further deterioration and maintain the genetic diversity of this species.     

Genetic diversity of natural populations of Larix principis-rupprechtii in Shanxi Province,China

Prince Rupprecht's Larch (Larix principis-rupprechtii Mayr.) is one of dominant components of middle and high elevation forests in North China. Shanxi Province is well known as “the Hometown of Prince Rupprecht's Larch” in China. In this study, six natural populations of this species across Shanxi were selected to investigate the genetic variation of the species using amplified fragment length polymorphism (AFLP) markers. Results showed that in comparison with some other species of Larix, higher genetic diversity was revealed at the species level for L. principis-rupprechtii (percentage of polymorphic loci PPL = 71.9%, Nei's gene diversity H_E = 0.225, Shannon information index I = 0.341). Most of genetic variation existed within populations (80.5%), while the genetic differentiation among populations was significant (p < 0.001) and higher (G_st = 0.194) than most other species of Larix. The differentiation can be attributed to the limited gene flow (N_m = 1.035) among populations, which could be due to the spatial isolation and habitat fragmentation. The six populations can be divided into three groups based on the Nei's genetic distances between populations (from 0.033 to 0.076). There was no significant correlation (r = 0.268, p > 0.05) between genetic distance and geographic distance among populations. The measures for in-situ or ex-situ conservation should be taken to preserve the genetic diversity of this species.     

Genetic variation within the sand-fixation species Caragana microphylla (Leguminosae) in Horqin sandy land detected by inter-simple sequence repeats analysis

Caragana microphylla is the most dominant and constructive shrub species in the Horqin sandy land in the northeast of China. We evaluated it's the level of genetic variation within and among populations sampled from two different populations types in Horqin sandy land by using inter-simple sequence repeat polymorphism (ISSR) molecular markers. The results showed that eight ISSR primers generated 106 bands, of which 87 were polymorphic. At the species level, genetic diversity was relatively high (P = 82.08%, h = 0.2831, I = 0.4233). Genetic variation in natural populations (h = 0.2152, I = 0.3169) was more than that in plantation populations (h = 0.2021, I = 0.3040). Based on Nei's G_ST value, more genetic differentiation among plantation populations was detected (G_ST = 0.7787). Six populations of C. microphylla clustered into two clades. These results have important implications for restoring and managing the degraded ecosystem in arid and semi-arid areas.