中国野生大豆遗传资源搜集基本策略与方法

遗传资源搜集原则是通过种子采集追求样本具有最高程度的遗传多样性。为了合理而有效地搜集野生大豆资源,近年来通过野生大豆居群考察和遗传多样性分析,初步明确了野生大豆资源居群的遗传多样性分布动态:遗传多样性地理的和生态的区域性、生态系统内居群的遗传相关性及各种生境下居群遗传多样性差异,从理论上奠定了野生大豆资源合理有效搜集的依据。根据居群遗传多样性的分布规律,初步建立了居群野生大豆资源的搜集策略和方法。     

江西野生大豆遗传多样性分析

利用48个SSR分子标记分析了192份采集于江西49个县（区）的野生大豆遗传多样性。结果表明,共扩增出等位基因343个,平均每对引物扩增出7.2个等位基因,平均基因遗传多样性指数0.7369,平均多态性信息含量（PIC）0.7060,表明江西野生大豆具有较为丰富的遗传多样性。不同纬度和不同海拔的野生大豆其遗传多样性不同,高纬度及低海拔地区野生大豆遗传多样性要高。192份野生大豆可聚类成三大类,聚类结果与地理来源较为一致。     

广东5个野生大豆居群的遗传多样性分析

采用SSR分子标记对来自广东省5个县野生大豆居群的遗传多样性进行了分析,为广东野生大豆资源保护和利用提供依据。结果显示:(1)5个野生大豆居群在60个SSR位点共检测出263个等位变异,同一位点上等位基因数目最多为10个,最少为2个,平均为4.38个;不同群体中特有等位基因数不同,其中连州(LZ)和南雄(NX)野生大豆的特有等位基因数目较多,分别为19个和16个;Shannon指数(I)变化范围为0.162~2.174,期望杂合度(He)的变化范围为0.073~0.899。(2)广东连州(LZ)野生大豆居群的遗传多样性最高,而仁化(RH)野生大豆的遗传多样性最低,二者的Shannon指数(I)分别为0.811、0.113;群体分子方差(AMOVA)分析结果揭示,居群间变异占51%,群体内变异占49%,且仁化居群与其他居群间基因流较小。(3)依据遗传距离可将连州(LZ)和连南(LN)聚类为一类,乳源(RY)和南雄(NX)为一类,仁化(RH)单独为一类。研究表明,广东不同野生大豆居群间遗传多样性差异较大,而且居群内基因类型多,其中连州(LZ)和乳源(RY)野生大豆居群的遗传多样性较高,证明广东野生大豆群体保存了丰富的基因资源。     

半野生大豆种质资源SSR位点遗传多样性分析

利用12对SSR引物对67份半野生大豆种质进行了遗传多样性的检测分析,结果表明,12个位点共检测到184个等位基因变异,平均每个位点等位基因数目为15．41个,平均多态性信息量,平均遗传多样性指数,平均遗传距离分别为0．849,0．706,0．118,根据SSR分析结果,按欧式距离将67份半野生大豆种质聚类并划分为5个组群。     

中国野生大豆(Glycine soja)遗传资源主要形态、遗传变异和结构

介绍了我国野生大豆遗传资源主要的形态类型、物种内遗传关系和遗传结构。进化的瓶颈不仅发生在由野生大豆到栽培大豆,也以另一种方式"分化瓶颈"出现于同性状的不同表型类型之间。野生大豆种内种子大小类型是否存在遗传分化?野生和半野生大豆的边界在哪?半野生大豆如何产生的?半野生大豆遗传上密切于栽培种还是野生种?百粒重3～4g的小粒半野生大豆与百粒重8.5g以上的特大粒半野生大豆是否有遗传差异?百粒重8.5g以上的特大粒半野生大豆是否属于栽培大豆?野生大豆的种皮色和种子大小哪个更能反映进化程度?栽培大豆基因是否已经渗入到野生大豆?对这些在学术界常年存在的疑问本文介绍了我们的研究答案。我们认为"真"半野生大豆不存在于现在中国半野生资源收集品中;一些野生大豆中的白花、灰毛、无泥膜性状来源于栽培大豆的基因渗透。     

山东省3个野生大豆居群生育期基因遗传多样性分析

以来自山东省3个居群的137份野生大豆种质资源为试验材料,利用等位基因特异性DNA标记进行生育期E1～E4基因型鉴定及遗传多样性分析。结果表明:在山东省野生大豆生育期基因E1～E4中,E1、E4位点上只检测出1个等位变异,皆为显性基因型E1、E4;E2、E3位点上变异较为丰富,分别以E2-in、E3-Ha为主;共发现5种基因型组合,其中E1E2-dlE3-HaE4基因型为优势组合。3个居群遗传变异不尽相同,临沂居群E2、E3位点以E2-in、E3-Mi为主,共有4种基因型组合,基因型组合以E1E2-inE3-MiE4为主。蓬莱和荣成居群,E2、E3位点以E2-dl、E3-Ha为主,共有3种基因型组合,以E1E2-dlE3-HaE4为主。在遗传多样性方面,山东荣成和蓬莱的亲缘关系较近,与临沂亲缘关系较远。遗传多样性最高的为临沂居群,其次是蓬莱居群,荣成居群。本研究结果可为山东省野生大豆种质资源利用提供理论依据,具有重要的应用价值。     

野生大豆种子库中同工酶水平上的遗传多样性的初步研究

采用聚丙烯酰胺凝胶电泳技术 ,对同一样地的不同时间和空间土壤中的野生大豆 (Glycinesoja)种子库内的 4种同工酶进行了分析 ,并利用数量分类学方法和统计学上的X2 测验 ,初步探讨了野生大豆种子库在此 4种同工酶水平上的遗传多样性的时空动态 .研究表明野生大豆种子库在同工酶水平上呈现出遗传多样性 ,其主要来自于由时间引起的环境异质性 .在时间变化上 ,同一层次的多样性呈现出极显著的差异 .在空间变化上 ,不同层次的多样性发生着不同的变化 .层与层之间同工酶的差异随时间的推移而加大 ,而且同一层次野生大豆种子库的平均杂合度也呈现出同样的变化规律 .这说明在对野生大豆种子库同工酶水平上的遗传多样性的影响程度上 ,时间比空间起着更大的作用 .     

野生大豆耐盐性研究进展

野生大豆对于拓宽大豆种质遗传基础和丰富大豆种质基因库具有重要意义.该文从野生大豆的资源概况及优良性状、耐盐机理和利用野生大豆提高栽培大豆耐盐性等三个方面,对近年来国内外有关野生大豆耐盐性的解剖结构、生理基础、分子生物学基础等方面的研究进展进行了系统综述,并提出野生大豆通过茎叶表皮上的"腺体"及对Na+和Cl-的排斥性,实现对盐渍环境的颉颃作用.较强的抗氧化能力、大豆异黄酮代谢和耐盐基因也是其适应盐渍环境的重要原因.今后应对野生大豆耐盐机理的遗传学基础进行深入研究,并通过种群保护以保障野生大豆的发掘鉴定和创新利用.     

国家基因库野生大豆微核心样本遗传变异性的SSR标记分析

用70对SSR引物对96份野生大豆微核心种质样本进行了遗传多样性分析.结果检测出1278个等位变异,平均每个位点有18.3个.地理区域群体水平显示,遗传信息指数(PIC)和特异等位基因变异数(NUA)以东北地区最高,长江流域次之,华南地区最低.在地理区域个体水平,遗传多样性的特征值以华南地区最高,依次由南向北降低,东北最低.我国华南野生大豆和东北野生大豆有显著的遗传分化.聚类分析结果显示,国家基因库野生大豆保存样本中的典型野生大豆和半野生大豆之间存在明显的遗传差异;地理上,种质的地理遗传分组表现弱的地域性.本研究中半野生大豆杂合性明显高于典型野生型的结果,支持关于这个类型起源于栽培和野生大豆天然杂交的假说,栽培大豆的基因可能已经流入到野生种内,某些百粒重小于3g的种质可能也是来源于野生和栽培大豆的天然杂交后代分离.     

中国野生大豆的遗传多样性和生态特异性分析

野生大豆（Glycine soja）是栽培大豆的祖先,为东亚特有种,大部分分布在中国。我们采用52对SSR引物和10个植物学性状,以遗传丰富度和Simpson多样性指数为指标,对来自中国3个地理生态区域涉及24个省区的196份野生大豆所构成的代表性样本的遗传变异进行了研究,以期从分子水平和表型水平两个层面上揭示中国野生大豆遗传多样性和地理生态特异性。结果表明：中国野生大豆群体SSR位点的等位基因平均丰富度（NA）和平均Simpson多样性指数（H）分别为16.1和0.852,高于栽培大豆（NA=11.4,H=0.773）,野生群体的遗传多样性明显高于栽培群体。3个地理生态群体中南方群体多样性最高（NA=12.9,H=0.842）,黄淮海群体最低（NA=11.4,H=0.805）,东北群体居中（NA=12.5,H=0.834）。群体间存在遗传分化,不同群体具有不同的特异等位基因,位点AW132402（A2连锁群）、Satt522（F）、satt150（M）、Sat_332（D1a）、Satt046（K）、sct_190（K）等的一些等位基因只在特定群体出现,表现出群体分化后的生态特异性。中国野生大豆植物学性状的群体变异丰富,平均Simpson多样性指数为0.710。地理群体间存在分化,最明显的是生育期性状的分化,反映了地理、光照和温度等生态因子的选择作用,其中南方地理群体多样性最高（H=0.671）。SSR分子标记和植物学性状所获结果相对一致,表明中国野生大豆地理群体间性状分化有其遗传分化的基础。     

新收集大豆种质资源主要品质鉴定与评价

对"十五"期间新收集、保存入国家种质资源库的841份大豆种质资源的蛋白质、脂肪两个主要品质性状进行了鉴定评价.结果表明,蛋白质、脂肪含量均近似正态分布,最大频度分别出现在41.01%～ 42.00%含量范围和20.01%～21.00%含量范围.与以前收集、保存的种质资源相比,新收集种质资源的蛋白质含量呈下降趋势,而脂肪含量和蛋脂总量呈上升趋势.不同类型种质资源的品质性状比较结果表明,地方品种的蛋白质总体水平明显高于育种材料、引进种质和选育品种3种类型,引进种质的脂肪、蛋脂总量的总体水平明显高于其他3种类型.国内种质资源高蛋白质大豆占有率高于引进种质资源;引进种质资源高脂肪、高蛋白兼高油的大豆占有率高于国内种质资源.     

新收集燕麦种质的遗传多样性和冗余性鉴定

从青海省4个县收集的60份燕麦样本中鉴别可能的重复材料,为编目和入库保存提供依据。通过名称与来源分析、形态变异性与相似性评价以及分子标记遗传多样性与冗余性鉴定,初步认为这些材料的来源不同,特性明显,遗传多样性丰富,具有一定的保存和利用潜力。但从中也发现同名材料较多,个别材料间遗传相似性较高,存在一定遗传冗余性,并鉴别出可能的重复材料,如白燕麦(1083)与白燕麦(1093)、燕麦(1225)与大燕麦(1226)等。本研究为资源工作者有效鉴别种质收集品中的重复材料、提高保种效率提供参考依据。     

广西部分地区野生茶树遗传关系EST-SSR标记分析

为了明确广西野生茶树种质资源的遗传背景,该研究从广西的宁明县、金秀县、苍梧县收集到14份地方野生茶树种质资源,以17个国家级茶树良种作为参照,采用EST-SSR分子标记技术,探讨了广西这三个地方野生茶树与国家级茶树良种间的亲缘关系以及广西地方茶树自身的遗传多样性。结果表明:15对EST-SSR引物共检测到68个等位基因,平均每个引物可扩增出4.53个,其中多态性位点为60个,多态性比率达88.2%。平均观测杂合度、平均期望杂合度、平均Shannon信息指数分别为0.42、0.55和0.97。PIC值在0.23~0.74之间,平均为0.52,多态性较好。遗传相似系数在0.53~0.9之间,平均值为0.71,31份供试材料在遗传相似系数为0.71分为5组群,76%参照品种聚在A组群,而广西本地的野生茶树资源则主要分布在B、C、D、E组群。利用该研究中的4对核心引物即可将31份供试材料全部区分开,挑选其中10个多态性较好的等位位点进行编码,构建31份供试种质的DNA分子指纹图谱。这表明广西野生茶树资源与国家级茶树良种间遗传差异较大、亲缘关系较远、遗传基础宽、多样性非常丰富,可作为茶树育种的亲本或开展茶树功能基因研究的材料。     

Population structure of the wild soybean (Glycine soja) in China: implications from microsatellite analyses

Background and Aims Wild soybean (Glycine soja), a native species of East Asia, is the closest wild relative of the cultivated soybean (G. max) and supplies valuable genetic resources for cultivar breeding. Analyses of the genetic variation and population structure of wild soybean are fundamental for effective conservation studies and utilization of this valuable genetic resource. Methods In this study, 40 wild soybean populations from China were genotyped with 20 microsatellites to investigate the natural population structure and genetic diversity. These results were integrated with previous microsatellite analyses for 231 representative individuals from East Asia to investigate the genetic relationships of wild soybeans from China. Key Results Analysis of molecular variance (AMOVA) revealed that 43·92 % of the molecular variance occurred within populations, although relatively low genetic diversity was detected for natural wild soybean populations. Most of the populations exhibited significant effects of a genetic bottleneck. Principal co-ordinate analysis, construction of a Neighbor-Joining tree and Bayesian clustering indicated two main genotypic clusters of wild soybean from China. The wild soybean populations, which are distributed in north-east and south China, separated by the Huang-Huai Valley, displayed similar genotypes, whereas those populations from the Huang-Huai Valley were different. Conclusions The previously unknown population structure of the natural populations of wild soybean distributed throughout China was determined. Two evolutionarily significant units were defined and further analysed by combining genetic diversity and structure analyses from Chinese populations with representative samples from Eastern Asia. The study suggests that during the glacial period there may have been an expansion route between south-east and north-east China, via the temperate forests in the East China Sea Land Bridge, which resulted in similar genotypes of wild soybean populations from these regions. Genetic diversity and bottleneck analysis supports that both extensive collection of germplasm resources and habitat management strategies should be undertaken for effective conservation studies of these important wild soybean resources.     

Development,validation and genetic analysis of a large soybean SNP genotyping array

Cultivated soybean (Glycine max) suffers from a narrow germplasm relative to other crop species, probably because of under‐use of wild soybean (Glycine soja) as a breeding resource. Use of a single nucleotide polymorphism (SNP) genotyping array is a promising method for dissecting cultivated and wild germplasms to identify important adaptive genes through high‐density genetic mapping and genome‐wide association studies. Here we describe a large soybean SNP array for use in diversity analyses, linkage mapping and genome‐wide association analyses. More than four million high‐quality SNPs identified from high‐depth genome re‐sequencing of 16 soybean accessions and low‐depth genome re‐sequencing of 31 soybean accessions were used to select 180 961 SNPs for creation of the Axiom^® SoyaSNP array. Validation analysis for a set of 222 diverse soybean lines showed that 170 223 markers were of good quality for genotyping. Phylogenetic and allele frequency analyses of the validation set data indicated that accessions showing an intermediate morphology between cultivated and wild soybeans collected in Korea were natural hybrids. More than 90 unanchored scaffolds in the current soybean reference sequence were assigned to chromosomes using this array. Finally, dense average spacing and preferential distribution of the SNPs in gene‐rich chromosomal regions suggest that this array may be suitable for genome‐wide association studies of soybean germplasm. Taken together, these results suggest that use of this array may be a powerful method for soybean genetic analyses relating to many aspects of soybean breeding.     

Genetic diversity assessment and ex situ conservation strategy of the endangered Dendrobium officinale (Orchidaceae) using new trinucleotide microsatellite markers

Dendrobium officinale (Orchidaceae) is an endangered plant species with important medicinal value. To evaluate the effectiveness of ex situ collection of D. officinale genetic diversity, we developed 15 polymorphic trinucleotide microsatellite loci of D. officinale to examine the genetic diversity and structure of three D. officinale germplasm collections comprising 120 individuals from its germplasm collection base and their respective wild populations consisting of 62 individuals from three provinces in China. The three germplasm collections showed reductions in gene diversity and average number of alleles per locus, but an increase in average number of rare alleles (frequency?≤?0.05) per locus in comparison to their wild populations. However, the differences in gene diversity between the germplasm collections and wild populations were not statistically significant. The analysis using STRUCTURE revealed evident differences in genetic composition between each germplasm collection and its wild population, probably because the D. officinale individuals with distinct genotypes in each wild population were unevenly selected for establishing its germplasm collection. For conservation management plans, we propose that D. officinale individuals with rare alleles need to be conserved with top priority, and those individuals with the most common alleles also should be concerned. The 15 new microsatellite loci may be used as a powerful tool for further evaluation and conservation of the genetic diversity of D. officinale germplasm resources.     

Genetic differentiation in relation to seed weights in wild soybean species (Glycine soja Sieb. & Zucc.)

Seed weight is one of the most important botanical and phylogenetic characteristics. The study objective was to understand whether there is genetic difference in different seed weights of wild soybean (Glycine soja Sieb. & Zucc.). A total of 563 wild soybean samples, which belonged separately to genebank germplasm accessions (220 samples), one regional population samples (293 plants) and one natural population (150 plants), were analyzed using microsatellite markers. Of four size classes, the smallest seed size type had the highest coefficient of variation in seed weight; small and large seed types had relatively great genetic differences. In the national genebank germplasm accessions, genetic diversity gradually decreased from quantitatively dominant small and middling seed types to less frequent large seed types. In the regional and natural populations, generally, small to middling seed sizes had higher genetic diversity than the smallest and larger seed sizes. Cluster analysis revealed genetic differences in seed size traits. The semi-wild type (Glycine gracilis Skvortzow) was the most genetically differentiated from other seed sizes. However, it was also clearly shown that the phylogenic genetic differentiation among seed sizes was less than the genetic differentiation among geographical habitat populations in the wild soybean species.     

棉花遗传多态性研究进展

从系谱分析、形态特征、生化及 DNA分子水平等方面分析了棉花遗传多样性的研究进展 .国内外的研究一致表明陆地棉品种间遗传多态性水平低 ,改进其遗传多样性是今后棉花遗传育种研究的重要内容 .加强对现有栽培品种、野生种质的研究利用和种质引进交流 ,多种育种技术综合运用和合理的植棉区域规划及多育种目标引导 ,是提高育成品种遗传多样性的重要途径 .并提出今后应加强棉花核心种质的研究和从基因组水平对棉花遗传多样性的研究