贵州桂花种质资源遗传多样性的ISSR分析

通过ISSR分子标记,对贵州不同地区的54份桂花种质进行了遗传多样性研究.选取11条多态性引物用于正式扩增,获得清晰、重复性好的DNA谱带93条,多态位性谱带80条,占总扩增带的86％,平均每个引物扩增8.45条;应用810和830的引物组合,构建了桂花种质的ISSR指纹图谱,可以有效区分所有供试材料;利用NTSYS和POPGENE 32进行数据分析,计算出相似系数与遗传距离,构建了54个样本的聚类树状图;以遗传相似系数0.69为阈值把54份供试桂花材料分为4类,聚类结果与地域及海拔具有一定相关性.因此,ISSR技术能够有效地用于桂花种质资源的鉴别及遗传关系的解析.     

利用ISSR标记解析黔东南玉米地方种质的遗传多样性

采用ISSR标记技术对来自贵州省黔东南州的43份玉米地方种质遗传多样性进行了评价.结果表明,用筛选出的17条引物进行PCR扩增,共扩增出清晰、重复性好的谱带261条,其中257条具有多态性,多态性比率为98.5%.品种间遗传多样性分析表明,其遗传相似系数变化范围为0.579～0.828.以ISSR构建的指纹图谱表明,其中有2条引物能有效地将43份玉米资源完全区别.表明贵州省黔东南州地方玉米种质间存在着丰富的遗传多样性.     

应用ISSR分子标记绘制红麻种质资源DNA指纹图谱

以6份红麻种质资源为材料, 对UBC807~UBC80等80个ISSR引物进行筛选, 筛选出多态性好的ISSR引物20个。利用这20个ISSR引物扩增来自国内外84份红麻种质资源, 共获得230条谱带, 平均每个引物扩增出11.5条谱带, 其中多态性谱带185条, 多态性条带比率为80.43%, 表明供试的红麻种质资源遗传多样性较丰富。以供试84份红麻种质资源的ISSR扩增谱带为基础, 建立了供试材料扩增条带指纹数据库的Excel文件。根据指纹图谱唯一性原则, 采用自行开发的DNA指纹数据分析软件, 再从20个多态性好的ISSR引物中遴选出UBC 813、UBC 825、UBC 836、UBC 888和UBC 889引物, 绘制出82个红麻种质资源的DNA指纹图谱, 为红麻种质资源分子身份证的构建奠定了基础。     

粤东地区橄榄种质资源遗传多样性的ISSR分析

该研究在于分析粤东地区橄榄种质资源的遗传多样性,从而为橄榄的保护和研究提供依据。利用ISSR分子标记对64份橄榄种质进行遗传多样性分析。共扩增得到128条谱带,其中多态性条带99条,多态性比率为77.34%。平均观察等位基因数为1.7734±0.4203、有效等位基因数1.4823±0.3888、Nei’s基因多样性0.2746±0.1975、Shannon’s信息指数0.4072±0.2721。64份种质的遗传相似性系数范围是0.5714~0.9379,平均遗传相似性系数为0.7793。聚类分析将64份种质分为5个类群,主坐标分析也将其分为5个类群。由结果可知,该地区橄榄种质总体遗传多样性水平较低,同时分子聚类分析结果与供试材料来源地无关。     

新疆薰衣草种质资源遗传多样性的ISSR分析

本研究应用ISSR标记对19份薰衣草种质的遗传多样性进行分析。结果显示:从100条引物中筛选出9条多态性明显的引物,19份材料DNA共扩增出94条谱带,其中多态性谱带40条,多态性比率为42.6%,平均每个引物扩增条带数为10.4条;9条ISSR引物可将所有样品完全分开,当遗传相似阈值为0.69时,可将样品分为3个类群:第Ⅰ类群13个品种(系)可分为2个亚类,第Ⅱ类群5个品种(系)可分为2个亚类,第Ⅲ类群1个品种(系)。样品间的遗传相似性系数为0.325~0.975(平均0.737)。群体的有效等位基因数、基因多样度、Shannon信息指数分别为1.454 0、0.280 5和0.435 4。研究结果表明,19个新疆薰衣草种质资源遗传多样性水平处于较高。     

贵州地方稻种资源的ISSR遗传多样性评价

利用ISSR标记对27份贵州地方稻种资源进行了遗传多样性鉴定与评价。结果表明,用筛选出的12条引物进行PCR扩增,共扩增出清晰、重复性好的谱带155个,其中127个具有多态性,比率为81.9%。ISSR指纹图谱表明,3个引物就能有效地将27份稻种资源完全区别;聚类分析表明,供试品种间的遗传相似性系数为0.555～0.942。在相似性系数为0.66时可将供试种基本按糯性与非糯性分为两大类群。     

不同来源棉花种质资源遗传多样性的ISSR分析

 采取ISSR分子标记对48份棉花种质资源的遗传多样性进行分析,从60条ISSR引物中筛选出11条引物,这11条引物共扩增出92个条带,平均每条引物扩增出8.36个条带;其中多态性带77个条带,多态率达83.70％。UPGMA聚类分析显示,48份材料的相似性系数（GS）变化范围在0.27～0.93之间。聚类将48个种质资源划分为 4个大类(GS=0.55),湛江野生棉、廉江野生棉与其它品种在遗传上有很大差别,属于较原始类型,归为一类;长绒棉与陆地棉品种存在明显的遗传差异也单独归为一类;其它不同省份的陆地棉品种在遗传上有较高的相似性,归为其它类型。分析结果表明,ISSR具有丰富遗传多样性和稳定性, 是一种较好的遗传分子标记,适宜于棉花品种遗传多样性分析     

22种石斛兰遗传多样性分析及DNA指纹图谱构建

为合理利用收集保存的石斛兰种质资源,采用ISSR分子标记方法对22种石斛兰的亲缘关系及遗传多样性进行分析。从100条引物中共筛选出6条扩增条带清晰、多态性高、重复性好的引物;利用筛选出的引物对22种石斛兰基因组DNA进行PCR扩增,共扩增出241条谱带,其中多态性谱带241条,多态性条带比例为100%;采用GenAlEx 6.5软件计算22种石斛兰的平均观测等位基因数(Na)为1.983,平均有效等位基因数(Ne)为1.167,平均Nei's遗传多样性指数(He)为0.133,平均Shannon信息多样性指数(I)为0.247,22种石斛兰表现出丰富的遗传多样性;采用NTSYS-pc 2.1软件计算22种石斛兰的遗传相似系数为0.698 4～0.878 7;基于遗传相似系数进行UPGMA聚类,在相似系数0.795处,可将22种石斛兰划分为10个类群,UPGMA聚类结果与传统的形态学分类结果一致。利用3对引物构建的DNA指纹图谱均可单独鉴别出22种石斛兰。该研究为石斛兰种质资源鉴定、杂交育种亲本选择等提供了理论基础。     

洋葱种质资源遗传多样性的ISSR分析

应用ISSR标记对32份洋葱种质资源的遗传多样性进行了分析。从31个ISSR引物中筛选出4条扩增产物条带清晰、多态性高的引物,在32份资源样品中共扩增出39条带,其中31条带为多态性位点,平均每个引物扩增的多态带数为7.75条,多态性条带比率（PPB）为79.48%。资源间的遗传相似系数在0.552~0.960之间,具有较为丰富的遗传多样性。ISSR聚类分析表明,在L取值为D=0.68时,可将32份洋葱资源分成5类：第一类包括18份种质资源,主要以Yellow Sweet Spanish系统为主;第二类包括1份种质资源,为Bejo Daytona;第三类包括3份种质资源,为Yellow Globe系统;第四类包括9份种质资源,为Yellow globe danvers系统;第五类包括1份种质资源,为Yellow Danvers system系统。较好地揭示了洋葱种质资源间的遗传多样性与亲缘关系,可为洋葱遗传育种和杂交亲本选择提供科学依据。     

马铃薯不同品种(系)遗传多样性的ISSR分析

本研究运用ISSR分子标记技术对30份马铃薯品种(系)材料进行多态性和聚类分析,分析各品种(系)间亲缘关系。结果表明:从56条ISSR引物中筛选出6条引物进行PCR扩增,共扩增出52条带,多态性条带为47个,多态性比率约为90.38%。通过UPGMA法对30份马铃薯品种(系)材料聚类分析显示,30份供试材料品种间遗传相似系数为0.40~0.95,平均相似系数为0.675;在相似性系数0.75附近,30份马铃薯品种(系)可分为6个大类,包括5大复合组和1个独立类。这些结果说明所选取的30个马铃薯品种(系)的遗传差异比较大,遗传多样性较丰富;该研究结果为马铃薯的遗传多样性利用及种质鉴定和杂交育种提供了有力的理论依据。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.     

Breeding forage grasses for organic conditions

Herbage yield trials are necessary to test if candidate varieties are well suited for organic conditions. In order to elucidate a particular suitability for organic conditions, we run such trials in parallel under both organic and conventional conditions. Here, we report on second and third year results of the sowings 2004 and 2005. These trials are part of a targeted breeding programme for organic conditions. Irregular colonisation of pure grass plots with adventitious plants, in particular white clover, was recognized as a major constraint to the quality of the results obtained under organic conditions. The coefficients of variance in dry matter yield almost doubled when compared to conventional trials, and significant differences in annual yield among varieties were rare. However, when herbage yield was corrected for the estimated fraction of adventitious plant colonization at each cut, the number of instances with statistically significant differences for annual yield among varieties increased more than fourfold. Dry matter yields under organic and conventional conditions were significantly and positively correlated. However, analysis of variance showed a significant culture type by variety interaction for annual dry matter yield in 12 out of 24 trials. When diploid and tetraploid varieties of the same Lolium species were tested in one common trial, only tetraploid varieties were identified as being particularly well suited for organic conditions, while in these trials, the great majority of apparently poorly suited varieties were diploid. This suggests that breeding tetraploid Lolium varieties is promising when aiming at a favourable response to organic agriculture.     

The performance of double or mixed pollinations with compatible and self-incompatible or incongruous pollen of pear and apple

Summary Six pear and five apple trials were carried out to ascertain the outcome of combinations of compatible pollen (C) with self (S) or incongruous pollen (I) as to the pollination index (PI=seeds/pollinated flower). The PI of the mixture C+I (1:5) was consistently depressed as compared to that of the control C. The results of the double pollinations S/C and I/C were affected by the temperature at pollination; their PI's at <15°C were twice as high as those at >15°C, being well above and below the PI of C in the former and latter case respectively. The opposite was true for the C/S combination, the PI of which increased with the pollination temperature; the PI of C/I did not differ much from the PI of C, irrespective of temperature. The conclusion was reached that the interaction previously and presently found between compatible and self-incompatible pollen also exists to a fair extent between compatible and incongruous pollen. However, in pear neither the mentor nor the pioneer pollen technique proved to aid its hybridization with apple, the formation of self seed was not observed either. In apple the production of apple × pear hybrids was likewise doubtful, but the double pollinations S/C and C/S formed 4–10% self seed.