东南亚茄子种质资源ISSR遗传多样性分析

为探讨东南亚和中国华南地区茄子育种资源的遗传差异,研究采用ISSR分子标记对来自泰国和马来西亚的10份茄子材料及中国和南美的8份材料进行遗传多样性分析。结果表明,17条ISSR引物共扩增出433条谱带,其中多态性条带390条,平均多态率为92%。17条引物在18份材料中的平均观测等位基因数、平均有效等位基因数、平均Nei’s基因多样度和平均香农信息指数分别为1.8971、1.4778、0.2850、0.4336,18份材料间的遗传相似系数GS在0.55~0.81之间。运用NTSYSpc2.10软件的UPGMA方法进行聚类分析,结果表明在遗传相似系数0.67时18份材料可分为2个类群,其中来自于东南亚的10份材料在第1类群,来自于南美的3份材料在第2类群。研究结果表明,东南亚茄子材料与中国和南美茄子材料间遗传多样性丰富,可为茄子种质资源的进一步研究和利用提供理论依据。     

亚洲棉种质资源的SSR遗传多样性分析

 对我国棉花中期库保存的200份不同地理来源的亚洲棉代表性样本进行了SSR遗传多样性分析,结果表明：亚洲棉分子水平的遗传多样性较高。83个多态性位点共检测到368个等位基因变异,其中多态性的等位基因数为329个,平均每个SSR位点3.964个。位点多态性信息量（PIC）变幅为0.010～0.882,平均0.578,PIC值大于0.7的标记有33个（占39.8%）。基因多样性（H′）变幅为0.031～2.163,有效等位基因数（Ne）变幅为1.010～8.496。华南棉区基因遗传多样性最高,其次为长江流域棉区、黄河流域棉区,从理论上支持被广泛接受的亚洲棉在我国的传播路线是由南到北,华南棉区是中棉种系的遗传多样性富集中心。利用软件NYSTS-pc2.20,采用类平均法(UPGMA)进行聚类分析,种质间SSR相似系数变幅为0.58～0.997,平均0.745,在阈值0.73处200份亚洲棉聚为8个类群,贵池小子棉白子单独聚为一群,与其他种质遗传距离较远。遗传距离和地理距离没有必然联系,但种质间亲缘关系处于极端远或极端近时,则地理距离一般也趋于较远或较近。     

陆地棉SSR核心引物筛选及95份骨干种质的遗传多样性分析

从391对棉花SSR引物中筛选出均匀分布于棉花26条染色体的52对核心引物,对92份陆地棉和3份亚洲棉骨干种质进行多样性分析,结果表明,52对引物的等位基因数范围为2～13,平均5.7692个,多态信息含量(Polymorphism Information Contents,PIC)在0.3457～0.8800间,均值...     

Allozyme diversity of Russian wildrye accessions

Analysis of genetic diversity among plant accessions plays an important role in developing strategies for plant breeding and the conservation of genetic resources. Therefore, we sought to estimate the extent of genetic diversity present among and within 29 Russian wildrye accessions, which were collected from widespread geographic sites. We assessed the genetic diversity of eight enzymes found in 29 Russian wildrye accessions using vertical polyacrylamide gel electrophoresis. The genetic diversity of each accession was estimated from standard genetic parameters that included (1) the number of polymorphic loci; (2) the average number of alleles per locus; (3) the observed and expected heterozygosity. The eight enzymes were encoded by 13 putative loci and 46 alleles. Allozyme analyses revealed a large number of polymorphic loci among the 29 accessions and some of the accessions carry rare alleles and trace their origin to sites in Xinjiang, China, where Russian wildrye is indigenous. The accessions with rare alleles require additional evaluation to determine whether they possess unique phenotypic traits which would be useful in applied plant breeding.     

Morphological and genetic diversity analysis of rice accessions (Oryza sativa L.) differing in iron toxicity tolerance

A major emphasis in breeding for iron toxicity tolerance in rice is to identify differences that are associated with resistance and harness them for genetic improvement. In this study, thirty accessions, including IRRI gene bank accessions, two varieties from Brazil, 8 cultivars from West Africa and 10 cultivars from Uganda were analyzed for sensitivity to iron toxicity, and genetic diversity using morphological and SSR markers. Two genotypes, IR61612-313-16-2-2-1 and Suakoko 8 showed significantly high resistance with an average score of ≤ 3.5 on 1–9 scale. The SRR markers were highly informative and showed mean polymorphism information content (pic) of 0.68. The PIC values revealed that RM10793, RM3412, RM333, RM562, RM13628, RM310, RM5749, and RM154 could be the best markers for genetic diversity estimation of these rice cultivars. Diversity at the gene level showed an average of 4.61 alleles ranging from 2 to 12 per locus. Mean gene diversity (H) value for all SSR loci for the 30 genotypes evaluated was 0.69 but was decreased to 0.53 when analysis was performed on Ugandan accessions. The low genetic diversity found among the Ugandan accessions is the evidence of a narrow genetic base, and such a scenario has a potential vulnerability for resistance break down. A low correlation was detected between the observed molecular and morphological datasets. This means that a combination of morphological traits and SSR analysis would be required when assessing genetic variation under iron toxic conditions, and could be a practical strategy for breeders when planning crosses. A distinction between the resistant and susceptible accessions in both phenotyping and SSR datasets suggests the presence of unique alleles that could be harnessed for improvement of rice against iron toxicity.     

海岛棉遗传多样性的SRAP标记分析

利用SRAP标记, 选用132对带型清晰的多态性引物, 对我国引入海岛棉以来培育的36个国内品种及20个国外品种进行遗传多样性分析。共检测到419个多态性位点, 每组合的多态性条带数从2~9不等, 平均为3.17。利用NTSYS-pc 2.10e 软件采用Jaccard’s相似系数和UPGMA方法进行聚类分析。结果表明, 大部分具有亲缘关系的品种聚在同类中, 说明其结果与系谱具有一定的相符性; 56个品种的平均遗传相似系数为0.497, 变化范围在0.312~0.876之间, 说明我国海岛棉品种在分子水平上存在较大差异; 我国3个育种时期育成品种的平均相似系数依次为0.501、0.507和0.548, 表明我国现在育成的品种相对于早期品种遗传多样性在逐渐降低。这些结果为我国海岛棉育种提供了有益的参考。     

普通菜豆根系相关性状的关联分析

幼苗期根系发育对作物的生长发育具有重要作用。利用生长袋纸培系统对324份普通菜豆种质的主根长、根干重、根体积、根表面积等9个根系相关性状进行表型鉴定,并结合覆盖全基因组、有多态性的116对SSR标记,利用MLM（Q+K）模型进行表型和标记的关联分析。表型分析表明,324份材料的9个根系相关性状表型变异丰富,平均变异系数的变动范围是10.09%~37.03%;基因型分析表明,116个多态性SSR标记共检测到919个等位变异位点,每个标记的平均基因多样性指数为0.59,多态性信息含量（PIC）平均值为0.54,显示这些标记具有较高的基因多样性;群体结构分析表明,供试材料分为两个亚群,与普通菜豆起源于两个基因库对应;关联分析结果显示,以P<0.01作为显著条件,共检测到48个显著标记位点,其中有10个位点同时与2个以上性状相关联,有5个位点与前人研究结果一致。研究结果为进一步理解普通菜豆根系的遗传机理提供了理论参考,也为分子标记辅助选择改良普通菜豆根系奠定了基础。     

大豆引进种质抗胞囊线虫病、抗花叶病毒病和耐盐基因型鉴定及优异等位基因聚合种质筛选

我国从美国、俄罗斯、日本等26个国家或地区共引进大豆种质3218份, 仅对部分种质进行了大豆胞囊线虫病(Soybean cyst nematode, SCN)、大豆花叶病毒病(Soybean mosaic virus, SMV)和盐敏感性的抗性鉴定, 但基因型的系统分析尚未见报道。本研究针对大豆抗胞囊线虫病3个基因(rhg1、Rhg4、SCN3-11)和耐盐基因(GmSALT3)开发KASP标记5个, 结合与大豆花叶病毒抗性相关的1个SCAR标记(SCN11), 对1489份大豆引进种质进行基因型鉴定。结果表明, 具有优异等位基因的种质共1084份; 携带3个位点优异等位基因的种质19份, 包括抗胞囊线虫病3个位点(rhg1、Rhg4、SCN3-11)叠加(Peking型)种质3份, 聚合抗胞囊线虫病基因和抗花叶病毒病标记7份, 聚合抗胞囊线虫病和耐盐基因2份, 聚合抗胞囊线虫病、抗花叶病毒病和耐盐基因7份; 携带4个位点优异等位基因的种质9份, 包括聚合抗胞囊线虫病基因和抗花叶病毒病标记6份, 聚合抗胞囊线虫病和耐盐基因2份, 聚合抗胞囊线虫病、抗花叶病毒病和耐盐7份; 携带5个位点优异等位基因8份, 聚合了抗胞囊线虫病、抗花叶病毒病和耐盐优异等位变异。在这些携带优异等位变异的种质中, 44份已由前人证明具有相应的抗性。携带3个或3个以上优异等位基因的36份种质中, 有52.78%种质的一种或两种特性已被报道。在不携带抗性优异等位变异的种质中, 93份已证明有耐盐性或对SMV3号株系抗性, 这些种质可能存在新的抗性(等位)基因。本研究利用高通量分子标记筛选出的携带抗病、抗逆优异等位基因的种质为我国大豆资源表型鉴定、抗源的快速筛选及利用提供理论依据和新思路。     

RFLP diversity within and between major groups of barley in Europe

Restriction fragment length polymorphism (RFLP) diversity has been determined and analyzed as expressed by 33 single‐ or low‐copy clone/ enzyme combinations at 32 loci distributed over all chromosomes of the barley genome within a sample of 223 European barley accessions comprised of pure line (single‐head progenies) genotypes. The accessions have been selected to include landraces and widely grown cultivars derived from crossbreeding during the 20th century in North‐, West‐ and Central European countries. Genetic diversity obtained from 83 alleles across all accessions is characterized by the diversity index H = 0.385. The diversity indices determined for landraces and cultivars were almost equal, with the difference between spring (H = 0.260) and winter (H = 0.415) barley approaching statistical significance, while comparisons of other groupings only revealed statistically insignificant trends. A more detailed analysis based on differences in allele frequency distributions at each locus (clone/enzyme combinations resp.) revealed very clear differences related to the existence, continuity and dynamics of changes in group‐specific RFLP profiles. With the majority (69%) of RFLP alleles at 23 out of 32 loci on all barley chromosomes involved, contributions from chromosomes 1H, 3H, 4H and 5H seem to be of special importance. Differences in the overall average of abundance indicate higher levels of genetic diversity within both groups of winter barley compared with both groups of spring barley, from which the most frequent alleles at 15 (2‐rowed spring barley) and 17 (6‐rowed spring barley) RFLP loci approach fixation. The results of this study are discussed in relation to the history of barley cultivation and barley breeding in Europe, and possible explanations for group‐specific differences in the RFLP profiles of landraces and cultivars as well as for the high levels of (nearly) fixed alleles of both subsets of spring barley, and with respect to progress in barley breeding that it has been possible to obtain within the rather narrow RFLP profiles.     

中国栽培和野生大豆农艺及品质性状与SSR标记的关联分析 II. 优异等位变异的发掘

在前文研究已检出与农艺品质性状显著关联的SSR位点的基础上, 本文进一步对与性状关联位点的等位变异作解析, 通过将携带某等位变异的所有材料表型均值与携带无效等位基因(null allele)材料表型均值做比较, 估计等位变异的潜在表型效应增量(减量), 进一步利用该信息估计位点增效(减效)等位变异的平均效应, 鉴别出一批农艺品质性状优异位点、等位变异及携带优异等位变异的载体材料。发现在栽培及野生种质中检出的优异等位变异有同、有异、有互补性。发现关联位点正、负效应等位变异均值间有差异, 可根据育种目标性状选择要求, 选取适合的位点及相应等位变异。同一标记位点可与多性状关联, 其等位变异在不同性状间各有其表型效应的方向和大小; 等位变异在相关性状效应上方向、大小的异同解释了性状间正、负相关的遗传原因。关联作图得到的信息可以弥补家系连锁法QTL定位信息的不足, 并直接利用等位变异信息进行亲本选拔、组合选配及后代等位条带辅助选择以提高育种成效。     

The genetic diversity of old and modern Siberian varieties of common spring wheat as determined by microsatellite markers

The objective of this study was to assess genetic diversity within old and modern common spring wheat (Triticum aestivumL.) varieties cultivated in Siberia and to find out whether old Siberian varieties could be a potential source for genetic diversity in modern wheat breeding in Siberia. A set of 54 varieties was analysed using 22 wheat microsatellite markers (WMS), determining 23 loci located on 19 different chromosomes. In total, 151 alleles were detected with an average of 6.6, ranging from three to 11 alleles per locus. The average genetic diversity value (polymorphic information content) was 0.70. WMS located in the B genome produced more alleles per locus (7.6) compared with WMS located in the A (6.0) and D (6.0) genomes. Genetic similarity values between varieties ranged from 0.19 to 0.96 and were used to produce a dendrogram. With a few exceptions the varieties studied were clustered in two nearly equal groups consisting of predominantly old (released before 1960) and modern (released in 1960‐90s) varieties, respectively. Genetic diversity values within these two groups were similar with 0.60 and 0.58, respectively. The numbers of group‐specific alleles were 34 and 29, respectively. A significant variation in frequencies of 79 shared alleles was observed. The results obtained by using genomic microsatellite sequences demonstrated that breeding has not resulted in a decrease in the genetic diversity in Siberian spring wheat. However, significant quantitative and qualitative changes in allelic frequencies of different loci were detected. It may be suggested, that old Siberian common spring wheat varieties are a potential basis for genetic diversity in modern wheat breeding in Siberia.     

大麦遗传多样性及连锁不平衡分析

为了合理评价引进种质资源,为大麦基因发掘及育种组合配置提供依据,选用分布于全基因组的64个SSR标记,对221份大麦材料进行了基因型分析。共检测到192个等位变异,变幅为2~7个;基因频率变异范围为0.0090~0.9729,平均0.3333;全部位点的基因多样性变化范围在0.0528~0.7807,平均0.4813;多态性信息含量(PIC)变异范围在0.0514~0.7464,平均0.4113。供试材料间遗传相似系数变幅为0.4844~0.9792,平均0.7023。221份材料被划分成两大群7个亚群,国内地方品种与1份北京品种为一大群,国内育种品种与所有国外引进品种为另一群。遗传结构分析与聚类结果基本一致,两大类群间的遗传距离为0.3358,且第二大群多样性比第一大群丰富。2016个SSR位点成对组合中,不论共线性组合还是非共线性组合,都存在一定程度的连锁不平衡(LD)。D′统计概率(P<0.01)支持的LD成对位点830个,占全部位点组合的41.2%,D′平均值为0.4,整体LD水平较高。栽培品种的LD水平高于地方品种,且现代遗传改良的目标性状集中于2H、4H、6H和7H染色体。     

中国红花种子醇溶蛋白遗传多样性研究

为了考察红花的种内变异,为进一步进行红花种质资源选育奠定基础.利用A-PAGE(Acid-polyacrylamide gel electrophoresis)技术对来源于中国不同地区的19份红花材料醇溶蛋白位点进行检测.结果表明,红花种子醇溶蛋白位点存在丰富的变异类型,共分离出13条迁移率不同的谱带,每份材料具有8～11条不等,平均10条.材料间平均遗传相似系数(GS)为0.759,变幅为0.385-1.000.在GS值为0.25的水平上,供试材料聚为两大类,聚类结果表明,红花醇溶蛋白图谱类型与其地理分布有很大的相关性.     

Genetic diversity of Chinese Spring Soybean Germplasm Revealed by SSR Markers

To use, maintain and increase crop germplasm collections efficiently, it is important to assess the diversity of these collections. In this study, 1383 accessions of Chinese spring sowing soybean ( Glycine max ) were used for SSR analysis. In total, 1111 alleles were detected among these collections with an average number of alleles (NA) of 18.52 per locus. The genetic diversity index (PIC value) varied from 0.456 to 0.928 with an average of 0.815. Intensive breeding of cultivars have led to a decrease of genetic diversity. Random-repeated sampling within landraces of different geographical regions suggested that the ranking of both average NA and PIC values among different geographical regions were North spring soybean (Nsp) > South spring soybean (Ssp) > Northeast spring soybean (NEsp), but because of the uneven distribution of SSR variation patterns, the differences between them did not reach a significant level. There was a relationship between genetic distances and geographical distances among soybean populations from different regions, indicating a certain degree of geographical differentiation among Chinese soybean germplasm collections.     

利用关联分析发掘小麦自然群体旗叶叶绿素含量的优异等位变异

为揭示小麦自然群体干旱胁迫条件下旗叶叶绿素含量的变化, 筛选相关标记的优异等位变异, 以262份小麦种质资源组成的自然群体为材料, 分别种植在北京的2个试验地点, 均设雨养和灌溉处理, 于开花期和灌浆期检测旗叶叶绿素含量。以分布于21条染色体的169个SSR标记检测所有材料的基因型, 利用STRUCTURE 2.3.2软件分析群体结构, 用TASSEL软件的MLM (mixed linear model)方法对小麦自然群体的旗叶叶绿素含量进行关联分析。在此基础上, 将携带某等位变异的所有材料表型均值与携带无效等位基因(null allele)材料表型均值比较, 估计等位变异的表型效应, 鉴别优异等位变异。共检测到2048个等位变异, 每位点2~37个等位变异, 平均12个。每位点的标记多态性信息量(PIC)为0.008~0.936, 平均0.628。在22个标记位点共检测出40个(次)与旗叶叶绿素含量极显著的关联, 其中11个标记位点有2次以上的关联, Xwmc419-1B和Xgwm501-2B分别有3次关联。在Xcfa2123-7A、Xgwm232- 1D和Xgwm429-2B位点分别检测到效应值大于4.0的等位变异。     

Genetic diversity in red clover (Trifolium pratense L.) revealed by morphological and microsatellite (SSR) markers

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.     

利用SSR标记分析橡胶草种质资源的遗传多样性

为了解橡胶草种质的遗传背景和遗传多样性,为今后橡胶草育种提供理论依据。利用23对SSR引物对96份橡胶草材料进行遗传多样性分析。结果显示,23对SSR引物通过扩增得到71个等位变异,等位变异范围2-6个,平均等位基因数为3.09个。通过聚类分析,俄罗斯材料和美国材料与新疆7个居群材料被分为2大类群,类群I包含所有俄罗斯和美国材料以及5份新疆野生材料,类群II包含其余新疆7个居群的材料;俄罗斯和美国材料同属于亚群A,平均遗传相似度为0.88,说明它们存在紧密的亲缘关系;新疆7个居群的材料被分为5个亚群,显示丰富的遗传多样性,而且相互之间存在复杂的遗传关系。本研究结果证明了SSR标记能够有效地用于橡胶草的遗传多样性研究,为以后的橡胶草种质收集和遗传育种提供重要依据。     

Genetic variation in South Korean natural populations of wild soybean (Glycine soja)

Summary Wild relatives are valuable genetic resources for crop improvement. Evaluating genetic variation in these species is not only important for their use in breeding programs, but will also provide information about evolution of crops. Seeds representing six natural populations were used to study the level of variation in the South Korean wild soybean. Electrophoretic assays of the seeds on horizontal slab gels were conducted to determine the genotypes of each natural plant at 35 loci in 17 isozymes and one protein. The results indicated a surprisingly high variation. The number of alleles at each locus was as high as four. Seventy two of the 94 reported alleles for the 35 loci were present in these populations. The average number of alleles per locus, 99% polymorphism and the expected heterozygosity in the total population were 2.1, 77.1% and 0.215, respectively. This amount of variation was not only higher than that reported for 857 soybean cultivars and wild soybean populations from other geographic regions, but also higher than the average for 123 self-fertilized plant species and 473 plant species of all mating systems. The high variation in the South Korean wild soybean as well as cultivated soybean indicated in this and other population genetic studies prompts us to propose that South Korea is one of the major soybean gene centers.     

Development, characterization and utilization of microsatellite markers in pigeonpea

Pigeonpea is a major legume of the semi‐arid tropics that has been neglected in terms of molecular breeding. The objectives of this study were to develop microsatellite markers and evaluate their potential for use in pigeonpea genetics and breeding. Two hundred and eight microsatellite loci were isolated by screening a non‐enriched partial genomic library. Primers were designed for 39 microsatellite loci, 20 of which amplified polymerase chain reaction products of the expected size. Nineteen of the primer pairs were polymorphic amongst 15 cultivated and nine wild pigeonpea accessions providing evidence for cross‐species transferability within the genus Cajanus. A total of 98 alleles were detected at the 19 polymorphic loci with an average of 4.9 alleles per locus. The observed heterozygosity ranged from 0.17 to 0.80 with a mean of 0.42 per locus. Less allelic variation (31 alleles) was observed within the cultivated species than across the wild species (92 alleles). The diversity analysis readily distinguished all wild relatives from each other and from the cultivated germplasm. Development of more microsatellites is recommended for future genomic studies in pigeonpea.     

QTL mapping and marker analysis of main stem height and the first lateral branch length in peanut (<Emphasis Type="Italic">Arachis hypogaea</Emphasis> L.)

Main stem height (MSH) and the first lateral branch length (LBL) of peanut (Arachis hypogaea L.) are important traits affecting plant shape and yield. Identification of quantitative trait loci (QTLs) related to these two traits, the prediction and cloning of candidate genes, and identification of plant height-related molecular markers are the basis for analysis of the molecular genetic mechanism of plant shape in peanut. In this study, a population of 151 recombinant inbred lines from a single seed, derived from a cross between variety 79266 (P1) and its variant progeny D893 (P2), was used to construct a peanut genetic map. The map consisted of 231 simple sequence repeat markers in 23 linkage groups, had a total length of 905.18 cM with average and minimum marker intervals of 3.92 and 0.1 cM, respectively. There were 11 and 16 QTLs detected in six environments for MSH and LBH with 6.26–22.53 and 5.89–21.63% phenotypic variation explained (PVE), respectively. Seven QTLs were detected in two or more environments: 3 QTLs for MSH (including Qmsh-14-3) with 7.66–22.53% PVE, and 4 QTLs for LBL (including Qllb-11-1) with 6.12–21.63% PVE. Qmsh-14-3 was steadily detected in five environments, localized between two markers, ARS376 and SEQ4G02, exhibited a genetic distance of 0.59–2.59 and 4.11–6.11 cM from the two markers, respectively. Qllb-11-1 was steadily detected in five environments, localized between two markers, ARS203 and AHS1413, exhibited a genetic distance of 1.06–3.06 and 0.23–2.23 cM from the two markers, respectively. There were 220 germplasm accessions used to detect the relationship between genotype and phenotypic values of traits at the marker loci ARS376 and SEQ4G02, average values of MSH and LBL were significantly higher for germplasm with the P1 compared to the P2 genotype. Determination of the marker loci ARS203 and AHS1413 indicated that average values of LBL were greater in germplasm with the P1 than the P2 genotype. The results provide references for fine mapping of QTLs for MSH and LBL, as well as breeding optimum plant-types in peanut.