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1.
Taxonomic understanding is a necessary prerequisite for intelligent germplasm maintenance and evaluation. Here, we use molecular evidence to address the generic position of the poorly known and morphologically unusual taxon Gossypium trifurcatum Vollesen. This species possesses dentate leaves, a feature not otherwise found in Gossypium L. but one that is common in Cienfuegosia Cav., a related genus in the small Malvaceous tribe Gossypieae. G. trifurcatum is a rare plant, restricted to deserts of Eastern Somalia and known from only two collections, the last in 1980. Using DNA extracted from an herbarium specimen, we amplified and sequenced the chloroplast gene ndhF. Phylogenetic analysis reveals G. trifurcatum to be cladistically nested within Gossypium. These data diagnose dentate leaves as an autapomorphy within a genetically diverse assemblage of African–Arabian species, which remain the least well-represented cottons in germplasm collections.  相似文献   

2.
Extensive germplasm resources are present in collections of Lotus corniculatus and L. uliginosus, two forage species that are valuable in situations where other legumes are not persistent. Naturalised populations in many regions are the primary gene pool for genetic improvement of these species and interspecific hybrids are an important source of variation for agronomic and forage quality traits. Although previous research has provided evidence that selection for optimal levels of condensed tannins and herbage productivity are feasible breeding objectives, less is known about correlations of condensed tannin with other parameters of nutritive value. A germplasm collection of 38 accessions in both species from 9 geographic regions was used as a data base to determine these correlations. Forage of each accession was sampled in two successive years from a field site in south-eastern Australia and analysed for condensed tannin, in vitro digestible dry matter, nitrogen, acid detergent fibre and neutral detergent fibre. In both species condensed tannin was negatively correlated with in vitro digestible dry matter and nitrogen. This result helped to identify potentially valuable accessions with low condensed tannin (<4% of dry weight) and high in vitro digestible dry matter (>70%). One of these was an interspecific hybrid of L. uliginosus and L. corniculatus, confirming the view that interspecific hybridization would be a valuable avenue for improvement of agronomic and forage quality characters in Lotus species.  相似文献   

3.
中华猕猴桃在中国潜在分布及其对气候变化响应的研究   总被引:5,自引:2,他引:3  
中华猕猴桃为中国特有果种,由于其独特的口感和较高的经济价值,近年来种植规模逐年扩大。在引种过程中,由于缺乏合理的布局规划和适生性分析,出现了品种单一化、易感病虫害等问题。近年来四川、陕西、贵州、重庆和湖北等猕猴桃主产省份相继开展了猕猴桃气候适宜性区划的研究,但目前的研究多未考虑未来气候变化对猕猴桃种植分布的影响,且伴随着气候变化的加剧,已有的研究结果已不能完全适应实际生产的需求。本文运用生态位模型软件MaxEnt,模拟和预测气候变化背景下大尺度范围中华猕猴桃适生区分布及其变化的可行性,以利于科学地优化产业结构、促进产业发展。基于当前数据和IPCC AR5提出的3种气候情景以及中华猕猴桃的分布信息,采用MaxEnt生态位模型和ArcGIS预测了中华猕猴桃的适生区及未来的变化趋势,用受试者工作特征曲线(receiver operating characteristic curve,ROC曲线)检测模型精度、刀切法(Jackknife test)筛选主导环境变量。结果表明,基于当前和未来情景构建的中华猕猴桃地理分布模型的AUC(area under curve)值均达到"极好"的标准,说明模型预测结果可用于本研究。当前气候条件下,中华猕猴桃的高适生区主要在四川、陕西、重庆、湖北、贵州、浙江、湖南、安徽、河南、江苏和甘肃等省份,面积达1.01×10~6 km~2。中适生区则以高适生区为中心向外扩散,包括河南、湖北、安徽、江苏和山东等地,面积为6.79×10~5 km~2。RCP2.6和RCP4.5排放情景下,中华猕猴桃高适生区的分布、面积及中心点位置都有所不同,面积均呈增加趋势;RCP8.5排放情景下,高适生区面积呈减少趋势。RCP4.5和RCP8.5排放情景下,中华猕猴桃高适生区中心点均有向北移动趋势。MaxEnt模型对未来气候变化条件下中华猕猴桃适生区的准确模拟与预测具有潜在应用价值,对该果树的气候适宜性区划具有重要指导意义。  相似文献   

4.
Wild annual Cicer gene pools contain valuable germplasm for chickpea improvement programs. Previous research showed that duplication might exist in accessions collected from these gene pools, which would hinder chickpea breeding and related research. AFLP (amplified fragment length polymorphism) markers were used to fingerprint the world collections of the primary and secondary gene pools including C. reticulatum Lad., C. bijugum K.H. Rech., C. judaicum Boiss. and C. pinnatifidum Jaub. et Sp. Duplicates were detected in a total of 24 accessions in both the gene pools, highlighting the necessity to fingerprint the germplasm. Genotypic difference was detected as gene pool specific, species specific and accession specific AFLP markers. These were developed into fingerprinting keys for accession identification between and within species and gene pools. Use of AFLP markers to detect duplicates and to identify accessions is a reliable method which will assist in the characterisation and use of wild annual Cicer germplasm in chickpea improvement programs. We recommend the procedure presented in this paper as a standard approach for the precise genetic identification and characterisation of future world collections of wild Cicer, to keep germplasm integrity and to benefit chickpea breeding and related research programs.  相似文献   

5.
Genetic Diversity in AA and CC Genome Oryza Species in Southern South Asia   总被引:3,自引:0,他引:3  
The CC genome of Oryza is found in nine species of Oryza that are distributed on all continents having a tropical climate. Three diploid Oryza species with CC genome are found in Africa and Asia to Papua New Guinea. In southern South Asia these three CC genome diploid species can be found, O. eichingeri and O. rhizomatis in Sri Lanka and O. officinalis in India. AA genome wild relatives of rice are also found in the same geographic region. Germplasm of both diploid CC and AA genome Oryza germplasm has recently been collected from Sri Lanka. AFLP analysis was used to compare the genetic diversity of the two Oryza genomes from a similar geographic region in southern South Asia. In addition, the diploid CC Oryza germplasm was also analyzed by RAPD and SSR methodologies and the combined results were analyzed. The results show that in southern South Asia the diploid CC genome species have a high level of genetic diversity compared to the diploid AA genome species. Molecular marker analysis revealed that populations of O. rhizomatis from northern and southeastern Sri Lanka are genetically differentiated. One accession of O. rhizomatis was aligned with O. eichingeri. This accession was collected from the site of O. rhizomatis that is the closest to a population of O. eichingeri. O. eichingeri showed lower genetic diversity than the other two diploid Oryza CC genome species. O. officinalis accessions from Assam, India, and China were genetically less diverged from O. eichingeri and O. rhizomatis than two accessions of O. officinalis from Kerala state, India. The first two authors contributed equally to this research  相似文献   

6.
Worldwide genetic diversity in 200 individuals comprising 41 castor bean accessions was assessed using amplified fragment polymorphisms (AFLPs) and simple sequence repeats (SSRs). We found that, despite surveying five continents and 35 countries, genetic diversity in castor bean germplasm is relatively low (overall H e = 0.126 for AFLPs and 0.188 for SSRs) compared to estimates of genetic diversity in other plant species. Our data also show no geographic structuring of genotypes across continents or countries within continents. An assessment of the congruence between AFLP and SSRs indicates a low correlation (R 2 = 0.19) between the two data sets, but each marker class nonetheless shows similar patterns of low-genetic diversity and a lack of geographic structure. Our data do suggest that SSRs yield a higher percentage of polymorphic loci, higher heterozyosity and a greater range of genetic distances, and are therefore more informative than are AFLPs on a locus-by-locus basis. Based on comparisons with numerous other plant species, we suggest that the lower genetic variation in this worldwide collection may be due to one or more factors including: sampling strategies that have not captured the full extent of genetic variation in the species; artifactual variation due to long-term germplasm storage and seed regeneration; or intense selection followed by domestic cultivation of a limited number of castor bean genotypes, which are widely propagated for their horticultural and agro-economic value.  相似文献   

7.
[目的] 在当前气候背景下预测板栗树种在中国的空间分布和生态特征,为板栗树种的合理引种、产业持续发展以及在水土流失地区的应用提供理论支撑。[方法] 基于261个分布点和40个环境变量,利用MaxEnt模型预测板栗树种的潜在地理分布并确定影响其分布的主要环境因子。通过对比国家级水土流失区和板栗树种的潜在分布确定其应用范围。[结果] 年均降水量、年平均温度、表层土壤酸碱度、平均日温差和温度季节变化方差5个环境变量对板栗树种适生区的分布贡献较大,累积贡献率在83%以上。同时板栗树种喜水怕涝,适合在酸性土壤中生长。潜在适生区面积总计为2.92×106 km2,约占国土总面积的30.46%,其中高度适生区主要分布在四川省和云南省的东北部,湖北省、湖南省和江西省的大部分地区,陕西省、河南省、安徽省、浙江省和山东省的部分地区。中度适生区分布以高度适生区为中心向外扩展。[结论] 对比中国水土流失重点预防和重点治理区,除青藏地区、西北地区和东北地区不太适宜板栗树种的引种外,在其他水土流失区都可以考虑选择板栗树种作为水土保持的经济树种。基于MaxEnt模型的板栗树种潜在分布预测拓展了人们对板栗树种分布和生态特征的认识,同时为水土保持功能区的树种选择提供了科学依据。  相似文献   

8.
Interest in bean genetic resources of Central America has resumed because of disease pressures (e.g., web blight, BGMV) and limitations of current bean varieties. As most of the diversity in landraces has been explored, focus is now on the exploration of wild forms of the primary gene pool and wild species of the secondary gene pool. A germplasm collection was carried out in the field and resulted in the collection of 29 wild populations for six Phaseolus species; it complemented field work done in 1987. Nine more populations were found for P. costaricensis, 10 for wild P. lunatus, one for P. oligospermus, one for P. tuerckheimii, four for wild P. vulgaris and four for P. xanthotrichus. Ninety-three herbarium voucher specimens were collected for 19 populations of the six species (deposited at CR). These results confirm the presence of wild P. vulgaris on both slopes of the central valley of Costa Rica, namely in the life zones bh-MB and bmh-P, and of P. costaricensis in the life zone bmh-MB. These life zones of limited range in Costa Rica have been heavily modified, thus fully justifying the germplasm collection for ex situ conservation. For both species the range of distribution in Costa Rica has been almost completely sampled. The life characteristics of each species that are relevant for their conservation in situ are briefly reviewed. Distribution ranges of each wild bean species are compared with the present extension of national parks, protected areas and fauna/flora sanctuaries, and suggestions for expanding such protected areas are made.  相似文献   

9.
Twenty nine germplasm lines of Chenopodium quinoa and two of Chenopodium berlandieri subsp. nuttalliae were evaluated for 12 morphological and 7 quality traits for two test seasons. The 19 traits were analyzed for cluster and principal component analysis. The first four PCs contributed 78.70 % of the variability among the germplasm lines. The first PC accounted for 39.5% of the variation and had inflorescence/plant, plant height and stem diameter as the traits with largest coefficients, all with positive sign. The characters with greatest positive weight on PC2 were days to maturity (0.309), inflorescence length (0.260) and branches/plant. All the germplasm lines were grouped into six clusters based on average linkage method. Cluster III had high values for seed yield and most of the quality traits but showed a small seed size. The dendrogram separated the two lines of C. berlandieri subsp. nuttalliae from the quinoa lines.  相似文献   

10.
Although common bean (Phaseolus vulgaris L.) is cultivated throughout India, the Himalayas hold largest diversity of bean germplasm. No studies on characterization of phaseolin types on this germplasm have been conducted earlier. In order to determine whether the common bean cultivars collected from various areas in the Northern Himalayas represent introductions from the Central American and Andean domestication centers or are local domesticates, we have analyzed the electrophoretic variation (SDS-PAGE) of phaseolin types in several bean accessions. A few species of Vigna were also included in this study to determine whether phaseolin (vignin in Vigna) patterns can be used to resolve the Phaseolus–Vigna complex. The present investigation on phaseolin (globulin) patterns of Phaseolus vulgaris and Vigna spp. clearly shows much variability in globulin patterns. Three new types of phaseolin patterns were recorded. An attempt to resolve phylogenetic problems in this complex was made using the phaseolin data.  相似文献   

11.
Calamintha nepeta and Micromeria thymifolia have been traditionally used in the Mediterranean area as condiments and medicinal plants for a long time. Whereas in parts of Italy C. nepeta (special recipes have been developed in Lazio and Tuscany) is also an established garden plant showing different evolutionary products and their interaction among each other and the wild progenitor, M. thymifolia is being developed into a new crop plant. Both plants and their uses are described with regard to Italy. There is a marked tendency to broaden the use of condiments and spices which results in new crop plants which have to be documented and elaborated in further studies. Many species of Labiatae are predisposed to use by man and new items can be found even in areas which have to be considered as well studied.  相似文献   

12.
Despite a raising interest on turfs in Italy, all theavailable varieties of this kind in the Country are of foreign origin, and areoften poorly adapted to the prevailing climatic conditions. This prompted tobegin a collection activity of indigenous turfgrass species, with the ultimategoal of identifying promising materials for future breeding based on localgenetic resources. The collection was carried out in three areas of Italy, viz.the northern Po Plain, the coastal region of Liguria, and the island of Sardiniathat are characterised, respectively, by subcontinental, warm temperate, andtypical Mediterranean climate. Altogether, 141 sites were visited, yielding 226accessions belonging to eight species of potential interest for turfs:Poa pratensis, Poa trivialis,Festuca rubra, Festuca arundinacea,Lolium perenne, Agrostis stolonifera,Agrostis tenuis, and Cynodon dactylon,this last being a warm-season grass. Poa pratensis andCynodon dactylon were mostly collected in northern Italyand Sardinia, respectively, whereas Festuca arundinacea andLolium perenne were rather ubiquitous. The collection sitesranged from 0 to 1040 m asl, but sites over 750 m wereonly visited in the inner part of Sardinia. All the accessions, collected aswhole plants, were transplanted at Lodi, northern Italy, where they are beingevaluated. Their preliminary evaluation for traits of importance for turf use,such as sward colour and overall quality, highlighted the great variation andthe occurrence of interesting accessions in all species. Other characters wererecorded, bearing specific importance in individual species, and in all casespromising accessions were identified. The germplasm of Festucarubra, Festuca arundinacea, and Loliumperenne proved highly infected by endophytic (symbiotic) fungi of thegenus Neotyphodium.  相似文献   

13.
Climate change is causing many organisms to migrate to track climatically-suitable habitat. In many cases, this will happen naturally, but in others, human intervention may be necessary in the form of ‘assisted colonisation’. Species re-establishments in suitable parts of their historic ranges provide an opportunity to conserve some species and to test ideas about assisted colonisation. Here, bioclimatic models of the distributions of two extinct British butterflies, Aporia crataegi and Polyommatus semiargus, were used to investigate the potential for re-establishment in Britain. Generalised additive models and generalised linear models were created to describe the species’ European distributions for the period 1961–1990. All models projected the British climate during this period to be suitable for both species. Thirty-year climate projections for the periods 1991–2020 and 2021–2050, and for three climate change scenarios, were then put into the models to generate projections of climatic suitability throughout the 21st century. British climate was projected to remain highly suitable for A. crataegi, but to decline somewhat for P. semiargus. Southern and eastern Britain were found to be the areas most likely to support suitable climate. This difference between the species appeared to be due in part to decreasing summer rainfall in climate change projections, as this should only benefit A. crataegi. It is concluded that, with further study of habitat requirements, both species could be reintroduced to Britain as part of a long-term European conservation strategy.  相似文献   

14.
15.
The genetic resources of Allium in India are potential source of genes for widening the crop genetic base. Despite their high economic value, limited number of germplasm accessions of wild species have been collected and conserved mainly due to difficult access to areas of occurrence. The present work mainly highlights information on species diversity distribution and utilization of wild Allium species to assess the value of Indian germplasm and prioritization for future collection and conservation programmes.  相似文献   

16.
We used amplified-fragment-length polymorphism (AFLP) markers to evaluate genetic variation in a set of bread wheat (Triticum aestivum L.) landraces and improved materials. Landraces collected from different geographic and agro-ecological zones in Pakistan in 1987, 1989 and 1991 were separated into two groups based on their geographic origins: northern (Himalaya) and south-western (Balochistan) Pakistan. Six AFLP primer combinations detected 453 AFLP markers in the 43 landrace accessions and four high-yield varieties (HYVs). Of these, 225 (49.67%) were rare (shared with < 5% of all accessions). Among these rare alleles, 23 (10.22%) were common in the Himalaya (shared with > 10% of accessions collected there) but were not found in Balochistan. We conclude that there is a higher probability of collecting rare alleles at overall, but which are in contrast locally common ones in the Himalayan region. Gene diversity was 0.17 in the Himalayan group and 0.15 in the Balochistan group. Considerable genetic variability was found in both groups. Accessions from different agro-ecological zones were indistinguishable by cluster analysis, indicating intensive seed trading within the country. Cluster analysis indicated that the landraces and the HYVs are genetically distinct; suggesting that genetic erosion of wheat landraces has been unlikely taken in place. This study provides an example of how analysis of existing materials and data, can serve as a basis for future collection planning and conservation policies.  相似文献   

17.
Genetic characterization of germplasm is important for setting objective guidelines for conservation. One common problem found in genebanks is determining the value of populations with insufficient or unreliable data regarding their geographic origin. In this study, a genetic analysis based on RAPD markers was conducted to characterize a `mystery' population of Solanum sucrense, a polysomic tetraploid potato (2n=4x=48), for which adequate documentation was lacking. The comparative analysis of genetic similarities between this mystery population and each one of 30 other S. sucrense populations in the genebank revealed that all populations within this species, including the mystery population, are significantly different from being duplicates, and are therefore worthy of separate conservation. RAPD markers also distinguished the mystery population from closely related tetraploid species S. oplocense, S. gourlayi and S. tuberosum ssp. andigena, suggesting that it is also not a duplicate of a population of these species. If RAPDs can clearly differentiate populations within highly heterogeneous tetraploids like S. sucrense, they should be generally useful for determining germplasm organization within potato species.  相似文献   

18.
Relationships between Arracacia species were studied according to 28 morphological discriminant characters, in 90 accessions: 83 Arracacia (Arracacia elata, A. incisa and A. xanthorrhiza), and seven accessions of Neonelsonia acuminata, which has been confused with A. elata. The geographic distribution of the Arracacia species was determined from the passport data of the 90 accessions. A. elata was clearly differentiated from N. acuminata according to morphological characteristics. The species A. incisa was more closely related to A. xanthorrhiza. Within A. xanthorrhiza two forms, monocarpic, and polycarpic, were identified. The distribution of wild Arracacia species in Peru is characterized by two main ecological zones: (1) a dry zone, like the western Yunga and western and inter-Andean valleys of the Quechua region (with seasonal rain from November to March), where the species A. incisa and A. xanthorrhiza are present, and (2) a humid zone, like the Eastern Quechua where A. elata is adapted. These informations could be useful to establish strategies for in situ and ex situ conservation and management of germplasm.  相似文献   

19.
A representative set of germplasm of genusVigna subgenus Ceratotropis specieswas used to analyze genetic diversity using amplified fragment lengthpolymorphism (AFLP) methodology. The germplasm was selected based onmorphological diversity and geographic origin and includes 18 out of the 21species in the subgenus Ceratotropis. Genetic diversitywithin and between taxa was measured using information generated by AFLP bandpolymorphism from which Jaccard's similarity coefficient and nucleotidediversity were estimated. The data were also used to generate phenograms tovisualize relationships among analyzed accessions. All species in sectionsCeratotropis and Aconitifoliae arewell separated. However, most of the species in sectionAngulares show a high level of similarity suggesting a lowlevel of genetic differentiation. In section Angulares onespecies, V. trinervia, is welldifferentiated from the other species and represents a separate evolutionarybranch between section Ceratotropis and other species insection Angulares. The relationships between the newlydescribed species V. aridicola,V. exilis, V.nepalensis and V.tenuicaulis and other species in the subgenusCeratotropis are described for the first time based on AFLPdata.  相似文献   

20.
Deforestation in southeast Brazil has led to the extinction of Hymenaea courbaril var. stilbocarpa and ex situ conservation has been established. In this study, the levels of genetic diversity and the effective population size of H. courbaril in a germplasm bank were investigated using six nuclear microsatellite loci. A total of 79 and 91 alleles were found in 65 seed-trees and their 176 offspring, respectively. Offspring have a higher average number of alleles per locus (= 15.2) than seed-trees (= 13.2), but lower observed heterozygosity (offspring: H o = 0.566; seed-trees: H o = 0.607). The estimate of outcrossing rate shows that the study population is perfectly outcrossed (t m  = 0.978, > 0.05). Significant deviations from random mating were detected through mating among relatives and correlated matings. The average variance in effective population size for each family was 2.63, with a total effective population size retained in the bank of 170.1. These results confirm that the preserved population of H. courbaril retains substantial genetic variability. Moacyr Antonio Mestriner and Ana Lilia Alzate-Marin—CEEFLORUSP Members.  相似文献   

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