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1.
In the subgenus Prunophora of the genus Prunus, many transitional traits presented in interspecific hybrids, the so-called ‘new species’, were frequently named due to the complicated botanical classification system. In this study, we used 16 nuclear simple sequence repeats (nSSRs) and 10 chloroplast simple sequence repeats (cpSSRs) to evaluate genetic relationships among 42 accessions, which included 15 putative interspecific hybrids, and then to reveal the speciation and differentiation in the subgenus Prunophora. In total, 231 and 27 alleles were observed in nSSRs and cpSSRs respectively; and with cpSSRs 20 haplotypes were revealed among the accessions. Furthermore, the haplotype and genetic structure analysis implied that (1) Prunus simonii Carr. might be a subspecies or a forma of Prunus salicina L., rather than an interspecific hybrid between P. salicina and Prunus armeniaca L., (2) Prunus limeixing Zhang et Wang was derived from a natural hybrid with P. salicina as its maternal progenitor and P. armeniaca as the female parent, and (3) Prunus cathayana Fu et al. (or kernel-using apricot) was an interspecific hybridization species of P. armeniaca (maternal parent) and Prunus sibirica L. (female parent). These results will be useful for clarifying the problems in the botanical classification, and facilitate the conservation and management of plum and apricot genetic resources in the Chinese National Germplasm Repository for Plums and Apricots.  相似文献   

2.
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3.
Motherwort (Leonurus cardiaca L.) is a medicinal plant indigenous to the Mediterranean regions in Europe and Asia. The objective of this study is to apply inter-primer binding site (iPBS) markers to assess the molecular variation and genetic relationships of 89 genotypes of motherwort to assist the genetic improvement of this species. The genotypes comprised 79 from Iran and 10 collected in Australia and 15 additional accessions of two related species (L. heterophyllus Sweet and L. sibiricus L.) collected in Australia, were also included. PCR of 7 iPBS primers (dominant markers) produced a total of 191 bands ranging from 180 to 4000 bp and the mean PIC for primers ranged from 0.2213 to 0.3206 with a mean value 0.2921. The mean expected heterozygosity (0.134), the mean unbiased expected heterozygosity (0.140) and Shannon’s information index (0.213) indicated a high level of inbreeding among the accessions tested. Ordination and cluster analysis showed that the genetic relationships among all accessions could be separated into three major groups—L. cardiaca, L. heterophyllus and L. sibiricus. However, among the 89 accessions of L. cardiaca, genotypes collected from the same geographic region tended to cluster together thus indicating greater genetic similarity. The Motherwort accessions originating in Iran are highly divergent and possess abundant genetic diversity and clearly provide a basis for selection and breeding. The iPBS PCR-based genome fingerprinting technology used in this study is low-cost and effective in differentiating accessions of motherwort and their related species.  相似文献   

4.
Significant genetic diversity was observed in 218 out of a total of 1309 accessions of amaranth (Amaranthus hypochondriacus L.) and its seven wild relatives, A. spinosus L., A. dubius Mart. ex Thell., A. hybridus L., A. tricolor L., A. cruentus L., A. caudatus L., A. retroflexus L. for 24 nutritional parameters including total oil content, fatty acid profile, total protein content and amino acid profile. Diversity for total oil content (6.42–12.53%), linoleic acid (25.68–54.34%), oleic acid (21.97–42.01%) of the total fatty acids, total protein content (7.84–18.01%), among important essential amino acids; lysine content (0.66–11.12 g/16 g N), methionine (0.35–4.80 g/16 g N) and half cystine and (0.12–8.32 g/16 g N) was reported. The un-weighted pair-group method using arithmetic average cluster analysis based on pair wise Euclidean genetic distance grouped the accessions into seven major clusters. Histidine, half cystine, tyrosine, essential amino acids, total oil content, linoleic acid and oleic acid content were the major parameters contributing significantly to genetic diversity. Present findings indicate that significant diversity exists for nutritional parameters in amaranth germplasm. The promising accessions with higher multiple nutritive traits; protein content (>16%), oil content (>11%), lysine content (>7.5 g/16 g N) and EAA higher than the FAO reported values, were identified. This is the first report on detailed nutritional analysis of diversity collected worldwide. These could be used as potential breeding material for nutritional enhancement through genetic improvement. This will help in overcoming the “triple burden” of malnourishment, hidden hunger, and obesity.  相似文献   

5.
Here, two Punica species, viz., P. protopunica Balf. fil., reported as native to Socotra, and P. granatum L., were compared for the first time. Analysis of one P. protopunica and eleven P. granatum accessions was performed using three molecular markers, i.e., sequence related amplified polymorphism (SRAP), target region amplification polymorphism (TRAP), and intron targeted amplified polymorphism (ITAP), along with analysis of pgWD40 sequences, a gene involved in anthocyanin biosynthesis. All markers revealed the relationship between the two species and placed them at 33% similarity. SRAP, TRAP, and ITAP generated a total of 299, 260, and 160 bands, respectively. Of these, 78, 74, and 41 bands were specific for P. protopunica, and 92, 85, and 57 bands, respectively, were shared between both species. Sequence analysis of pgWD40~870 bp amplicons exhibited 100% identity among P. granatum accessions and 98% identity to that of P. protopunica. Phylogenetic analysis of WD40 sequences from monocot and dicot species, including both Punica species confirmed the relation between P. protopunica and P. granatum, supporting earlier reports that P. protopunica could be an ancestral species of P. granatum. Furthermore, the genetic diversity among and within P. granatum accessions from Egypt (3), Mexico (5), and Yemen (3) was assessed. Molecular marker-based relationships among region-bulked accessions was approximately the same (~90% similarity), whereas the degree of genetic variation was altered within each region. Specific bands (alleles) for accessions of each region along with those shared among them were identified. Thus, these bands could be used for pomegranate genotyping and breeding programs.  相似文献   

6.
The present study investigated genetic diversity, structure and hybridization in a collection of the endangered wild pear species Pyrus pyraster (L.) Burgd. A total of 278 putative ‘true type’ P. pyraster trees originating from seven populations in the federal state of Saxony in Germany were analyzed along with 35 pear cultivars commonly cultivated in Saxony. The genetic analysis was performed using nine nuclear microsatellite markers (ncSSR) and two paternally inherited chloroplast marker (cpDNA) amplifying in the intergenic spacer region trnQ–rps16 and the intron region rps16. On basis of the ncSSR dataset after STRUCTURE analysis 80 % of the wild pear individuals were assigned as ‘true type’ P. pyraster genotypes. The cpDNA analysis showed shared haplotypes in P. pyraster and P. communis but with an unequal frequency in both species. The analysis of molecular variance resulted in a moderate (ncSSR) and great (cpDNA) variation among ‘true type’ P. pyraster and the pear cultivars. The genetic diversity in the ‘true type’ P. pyraster populations was still high and the genetic structure between the populations low (ncSSR and cpDNA) indicating a genetic exchange between the populations by pollen and seeds. The clear discrimination between the P. pyraster and P. communis confirms our expectation of the existence of ‘true type’ P. pyraster individuals in the study area. The existing genetic integrity and the high genetic diversity argue for the implementation of preservation measures in P. pyraster.  相似文献   

7.
Little is known regarding the effect of fragmentation and human agricultural management on the genetic variation and gene flow of Cucurbita pepo L., 1753 in moderate fragmented areas in central Guatemala. We hypothesize that the genetic variation of C. pepo is affected by forest fragmentation and by traditional agricultural management. Therefore, we aim to determine: (1) the genetic diversity and genetic structure of C. pepo in the Cloud Forest Corridor (CFC) (2) the extent of genetic admixture between commercial variety (CV) and traditional landraces (TL) of C. pepo, (3) the effect of habitat fragmentation in the population genetics of C. pepo with a landscape approach, and (4) the potential relationship between traditional management practices and genetic diversity of C. pepo in the CFC. We detected the existence of high level of genetic diversity (AR = 3.43; He = 0.50), inbreeding (Fis = 0.25) and moderate population structure of C. pepo in the CFC (Fst = 0.16). No correlation between landscape and genetics was found. Also, we found high genetic admixture between CV and TL. It seems that human practices, mainly related with seed exchange patterns, could affect genetic diversity of C. pepo in the CFC. C. pepo populations in the CFC are structured, with inbreeding, and show admixture with the CV, an aspect that could affect its genetic diversity. The agricultural management influenced the population genetics of C. pepo in the CFC, but the landscape did not. We suggest that special efforts should be made to preserve the diversity of this important indigenous food source for Guatemalan people as well as their management practices.  相似文献   

8.
Genetic diversity of 139 accessions of diploid Triticum species including Triticum urartu, Triticum boeoticum and Triticum monococcum was studied using 11 SSR (simple sequence repeats) markers. A total of 111 alleles with an average of 10 alleles per locus were detected. The polymorphism information content (PIC) of each SSR marker ranged from 0.30 to 0.90 with an average value of 0.62. Among the three Triticum species T. urartu had the highest number of total alleles (Na?=?81), private alleles (Npa?=?15) and showed higher genetic diversity (Hex?=?0.58; PIC?=?0.54). The genotypes from Turkey exhibited the highest genetic diversity (PIC?=?0.6), while the least diversity was observed among 4 Georgian accessions (PIC?=?0.11). Cluster analysis was able to distinguish 139 wheat accessions at the species level. The highest genetic similarity (GS) was noted between T. boeticum and T. monococcum (GS?=?0.84), and the lowest between T. urartu and T. monococcum (GS?=?0.46). The grouping pattern of the PCoA analysis corresponded with cluster analysis. No significant differences were found in clustering of T. urartu and T. monococcum accessions with respect to their geographic regions, while within T. boeoticum species, accessions from Iran were somewhat associated with their geographical origin and clustered as a close and separate group. The results from our study demonstrated that SSR markers were good enough for further genetic diversity analysis in einkorn wheat species.  相似文献   

9.
Panax species have been used as medicinal plants in China and adjacent areas, but the difficulty in wild species identification based on morphological characters prevents the exploration and utilization of these resources. To assist in identifying the species, three plastid intergenic spacers and four nuclear genes of 129 samples from 20 different localities were sequenced to conduct the clustering analyses. P. stipuleanatus and P. notoginseng were relatively easy to be distinguished from other species based on morphological characters and clustering results. Three samples collected from Laos grouped together with those collected from Jinping (China), and they were all identified as P. vietnamensis. However, the fourth one LW4 had closer genetic relationship to P. notoginseng than to P. vietnamensis. Although they were morphologically different in petiolule length, the samples preliminarily identified as P. zingiberensis grouped together in the clustering analyses, and the results of STRUCTURE analysis suggested that samples collected from Zhenyuan shared some genetic component with P. vietnamensis. As for the samples identified as P. japonicus and P. wangianus, there were so many variations in leaves, rhizomes and rootstocks that it was difficult to differentiate them from each other. Molecular data also showed that these taxa were genetically admixed and the samples identified as P. wangianus could be classified into P. japonicus. The nucleotide diversity results indicated that the wild relatives had more substantial genetic diversity compared to P. notoginseng.  相似文献   

10.
Yam bean [Pachyrhizus DC.] is a legume genus of the subtribe Glycininae with three root crop species [P. erosus (L.) Urban, P. tuberosus (Lam.) Spreng., and P. ahipa (Wedd.) Parodi]. Two of the four cultivar groups found in P. tuberosus were studied: the roots of ‘Ashipa’ cultivars with low root dry matter (DM) content similar to P. erosus and P. ahipa are traditionally consumed raw as fruits, whereas ‘Chuin’ cultivars with high root DM content are cooked and consumed like manioc roots. Interspecific hybrids between yam bean species are generally completely fertile. This study examines the genetic diversity of the three crop species, their potentials for breeding and the identification of useful traits to differentiate among yam bean genotypes and accessions. In total, 34 entries (genotypes and accessions) were grown during 2000?2001 at two locations in Benin, West Africa, and 75 morphological and agronomical traits, encompassing 50 quantitative and 25 qualitative characters were measured. Diversity between entries was analyzed using principal component analysis, cluster analysis, multivariate analysis of variance and discriminant function analysis. Furthermore, phenotypic variation within and among species was investigated. Intra- and interspecific phenotypic diversity was quantified using the Shannon–Weaver diversity index. A character discard was tested by variance component estimations and multiple regression analysis. Quantitative trait variation ranged from 0.81 (for total harvest index) to 49.35% (for no. of storage roots per plant). Interspecific phenotypic variation was higher than intraspecific for quantitative traits in contrast to qualitative characters. Phenotypic variation was higher in overall for quantitative than qualitative traits. In general, intraspecific phenotypic variation ranged from 0.00 to 82.61%, and from 0.00 to 80.03% for quantitative and qualitative traits, respectively. Interspecific phenotypic variation ranged from 0.00 to 95.02%, and 0.00?81.58% for the two trait types, respectively. The Shannon–Weaver diversity index (H′) was in general high and over 0.80 for most of the trait. Diversity within P. tuberosus was higher than within P. erosus and P. ahipa. Across the 50 quantitative and 25 qualitative traits, the Shannon–Weaver diversity index of intra- and interspecific variation was around 0.83 and 0.51, respectively and was lower for qualitative than for quantitative traits. Monomorphism was observed in eight qualitative traits and one quantitative character. The first, second and third principal components explained, respectively, 39.1, 21.3 and 8.3% of the total variation in all traits. Pachyrhizus erosus, P. ahipa, and P. tuberosus (‘Chuin’ and ‘Ashipa’) were clearly separated from each other by these analyses. Multivariate analysis of variance indicates significant differences between Pachyrhizus species for all individual or grouped traits. Discriminant function analysis revealed that the first two discriminant functions were almost significant. Biases due to unbalanced sample size used per species were small. Within each species a similar amount of diversity was observed and was determinable to 70% by only ten traits. We conclude that the cultivated yam bean species represent distinct genepools and each exhibits similarly large amounts of genetic diversity.  相似文献   

11.
Several botanical studies have been conducted in different parts of Oman, but knowledge about agro-biodiversity in the rapidly decaying ancient mountain oases of this country remains scarce. To fill this gap we assessed the genetic resources of three mountain oases in the al-Hajar range using a GIS-based field survey and farmer interviews. While arid conditions prevail throughout the mountain range, the different elevations of Balad Seet (950–1020 m a.s.l.), Maqta (930–1180 m a.s.l.) and Al Jabal al Akhdar (1750–1930 m a.s.l.) provide markedly differing agro-climatic conditions. Overall, 107 different crop species were identified belonging to 39 families. Species number was highest among fruits (33 spp.), followed by vegetables (24 spp.). Intensive irrigation allows cultivation of a broad range of species at all oases. However, the number of species varied significantly between sites. Fruit species diversity and homogeneity of distribution of individual fruit species was highest at Balad Seet and lowest at Maqta as indicated by respective Shannon indices of 1.00 and 0.39 and evenness values of 32% and 16%. Century plant (Agave americana L.), faba bean (Vicia faba L. var. minor Peterm. em. Harz) and lentil (Lens culinaris Medik.) were identified as relict crops, supporting oral reports of past cultivation and providing evidence of genetic erosion. Some species, such as the temperate fruits of Al Jabal al Akhdar, were exclusively found at the coolest site, while others only occurred at the hotter locations. Overall greatest species similarity was found between Balad Seet and Al Jabal al Akhdar as indicated by a Sørensen coefficient of similarity of 67%. At all oases a multilayered vegetation structure dominated with a canopy, an understory and a ground layer. Greatest species richness was recorded in the lowest stratum. Overall the study shows a location-specific but surprisingly diverse mosaic of crops in Omani mountain oases which merits further studies and conservation efforts.  相似文献   

12.
Chinese cherry (Prunus pseudocerasus Lindl.) is an indigenous fruit crop with high nutritional and ornamental value. It is widely cultivated in China, and many landraces have accumulated in large distribution regions. Genetic diversity analysis of Chinese cherry landraces is useful for breeding programs, as it helps to select genetic material to be used for further crossing. In this study, 110 Chinese cherry accessions from nine populations were assessed using fifteen morphological traits and seventeen ISSR markers. High average coefficient of variation (CV?=?17.43%) was detected based on morphological analysis. For molecular characterization, the global gene diversity (h?=?0.2816) and Shannon information index (I?=?0.4253) suggested a moderate high level of genetic diversity. Model-based STRUCTURE and principal coordinate analysis revealed three and two major gene pools based on morphologic and molecular data, respectively. Distinct distribution patterns of genetic variation between samples from southwest China and north China indicated two potential original domestication locations. We inferred that botanical features such as predominantly selfing characteristics, long lifespan, and insects-pollinated trait lead to the survival of abundant genetic variation and special genetic structure. This study provided morphological and molecular evidences for understanding genetic diversity and new insights into genetic consequence of populations for Chinese cherry landraces. Important implications for breeding programs and resources conservation were also provided.  相似文献   

13.
Wild Cicer species are considered as useful genetic resources for resistance to biotic and abiotic stresses due to limited resistance in cultivated chickpeas. As a wild perennial species in the genus Cicer L., Cicer isauricum P.H. Davis is an endemic species to Turkey and endangered status according to the International Union for Conservation of Nature criteria. Here we report on its eco-geographic distribution and environmental stresses that affect the species, and advocate for its in situ and ex situ conservation. A new population of the species was discovered in Geyikbay?r?, Güllük Mountains in Antalya, Turkey. Cicer isauricum not only suffers from significant biotic stresses such as ascochyta blight [Ascochyta rabiei (Pass.) Labr.], pod borer (Helicoverpa armigera Hübner) and broomrape (Orobanche sp.), but is also subjected to drought and heat stress in its habitat. Infection with ascochyta blight in natural habitats was diagnosed by molecular techniques, and pod borer and broomrape were observed only phenotypically. PCR amplification of the internal transcribed spacer region of genomic DNA from cultured fungal isolates, yielded sequences with 100% nucleotide identity with the corresponding sequence in GeneBank for Didymella rabiei Kovachevski (anamorph: A. rabiei). The pathogen may have co-evolved with C. isauricum in the newly discovered site. Because C. isauricum is exposed to drought and accompanying heat stress in its natural habitat, it appears able to tolerate heat stress up to 45 °C during podding stage and terminal drought in late summer from its woody, deep rooting. C. isauricum bears multiple flowers per axil, a potentially useful trait in cultivated chickpea. In conclusion, C. isauricum is a potential genetic source for resistance to biotic and abiotic stresses, in need of greater protection due to its endangered status.  相似文献   

14.
The wild Brassica juncea (L.) Czern. et Coss., systematically belonging to the genus Brassica L. in the Cruciferae family, has become a noxious weed for cropping systems nowadays. Here, simple sequence repeat (SSR) markers were applied to investigate the genetic diversity, genetic structure and migration routes of the wild B. juncea populations in China. The results showed that a total of 90 alleles, with extensive allelic diversity, were observed at the 11 SSR loci of the wild B. juncea. The STRUCTURE analysis indicated that all the 25 wild populations were best described as belonging to two lineages. High Fst value (0.568), together with the partitioning, provided significant evidence for lineage differentiation in wild B. juncea. The high differentiation between the two lineages was, perhaps, due to limited gene flow (Nm?=?0.301) of this species. The analysis of molecular variance with distances among individuals corrected for the dominant nature of SSRs showed that most of the variation (59%) occurred within populations, and the remaining 41% variance was attributed to differences among populations. The distribution of diversity across China was significantly geographically dependent. NJ cluster analysis, based on genetic distance, grouped populations geographically, which further corroborated spatial pattern of two lineages. Based on these results, two routes were proposed for the migration of wild B. juncea in China after its origin from northwest China, heading east along the Yellow River or Yangtze River, respectively. We concluded that China, especially the northwest, is one of the primary origins of B. juncea.  相似文献   

15.
Potentilla alba L. is a valuable medicinal plant widely used in folk and traditional medicine and particularly promising in complex treatment of thyroid pathology. Natural resources of this species are insufficient due to ever-growing use in contemporary medicine. Comprehensive investigations of different P. alba populations are essential for the successful extension of P. alba plantings. Aiming for a better understanding of karyotype structure, chromosome behaviour in meiosis and developing new diagnostic characters, we performed molecular cytogenetic characterization and leaf structure and ultrastructure analyses of two introduced P. alba samples originating from different habitats. Based on chromosome morphology, distribution of 45S/5S rDNA and DAPI-banding patterns, all chromosomes in the karyotypes were identified and the P. alba chromosomal idiogram was constructed. Our findings confirmed P. alba karyotype stability and also revealed several diagnostic characters of this species: the features of cells of upper and lower leaf epidermis, the presence of calcium oxalate druses and three types of leaf indumentum, essential for evaluation of genetic diversity in different populations, validation of raw materials and further selection progress. The meiotic abnormalities were detected probably related to low pollen activity and indicated the advantages of vegetative propagation in the development of a P. alba plantation system.  相似文献   

16.
Genetic erosion in cultivated wheat provides a good reason for studying genetic diversity in crop wild relatives. In the present study, genetic diversity of 32 accessions belonging to T. boeoticum species collected from different parts of Iran were evaluated using 13 morphological traits as well as ten inter-simple sequence repeat primers. Statistical analysis for morphological traits showed significant differences among accessions (except number of fertile tillers and total tillers per plant). In principal component analysis, the first three PCA showed 82.65 % of the total morphological variation. Based on the morphological traits, accessions were separated into two main groups by cluster analysis. In molecular analysis, polymerase chain reactions amplified 105 DNA fragments, out of which, 95 (90.47 %) were polymorphic. From geographic perspective, the accessions sampled from western and southwestern of Iran showed the highest and lowest polymorphism, respectively. However, the maximum values of effective number of alleles (Ne), Nei’s gene diversity (He) and Shannon’s information index (I) was related to accessions collected from NW regions. Also, according to cluster analysis and PCoA plot genetic diversity was not related to geographical distribution. Overall, our results revealed a remarkable level of genetic diversity among studied Iranian T. boeoticum accessions; especially accessions collected from Kermanshah and Lorestan provinces, which can be of interest for future breeding programs. So, conservation of germplasm of these areas is recommended.  相似文献   

17.
Investigating population genetic structure and diversity, and resistance to pathogens in crop wild relatives are key steps to assess appropriate conservation and breeding programs. The Caucasian wild apple (Malus orientalis Uglitzk.) is an emblematic fruit tree of the Hyrcanian forest and is supposed to be a contributor to the cultivated apple genome (Malus domestica Borkh. Yet, no study has investigated its population structure, diversity and susceptibility to the two main pathogens of apples, the apple scab (Venturia inaqualis) and the powdery mildew (Podosphaera leucotricha). Here, we investigated population genetic structure and diversity of M. orientalis in the Hyrcanian forest as a mean to identifying future targeted populations for apple conservation and breeding programs. We genotyped using multilocus microsatellite 100 M. orientalis trees sampled in 14 sites. These trees were also screened for presence/absence of six (Rvi6, Vr, Rvi4, Rvi15, Rvi5 and Rvi11) and three (Pl-1, Pl-w, Pl-d) resistance genes to the apple scab and the powdery mildew respectively. Our results showed significant but weak between-site genetic differentiation and isolation by distance pattern suggesting substantial historical gene flow for M. orientalis in this area. We also detected a West-Eastern genetic structure across the Hyrcanian forest with five main populations showing admixture. We also showed a high diversity of resistance genes to apple scab across sites; in contrast, we only found one resistance gene to powdery mildew. These results are a first glimpse to settle wild apple conservation programs in Iran and pinpoint Iranian wild apple populations as an untapped source for apple breeding.  相似文献   

18.
Perception of farmers’ about the use of pesticides and genetic erosion of tetraploid wheat landraces of Ethiopia was assessed through focus group discussions with farmers, on-farm observations, personal interviews with farmers, by using structured questionnaires of temporal and spatial methods. A total of 1496 farmers from seven provinces in the country were interviewed. Farmers’ knowledge about pesticide increases suggests that they are not happy on using chemicals because of their negative impact on farm land. About 75 % of the farmers believe that, although the use of pesticides may increase the production of wheat, it has a negative impact on (human) health and environment. Women showed a higher concern for pesticides’ harmfulness than men. Farmers’ valuation of genetic erosion was estimated as reduced importance of landraces, as shown by a the lower proportion of landraces either grown or sold on the market. The four most important factors cited for loss of landraces were reduction in land area per capita, displacement by released/modern varieties of hexaploid wheat and teff, reduced benefit from landraces, and displacement by other crops and chat. Genetic erosion of 100 % was observed for Triticum dicoccon in the provinces of Gojam and Gonder and for T. polonicum in Tigray and Gojam. Overall, genetic erosion in the country was 32.0, 35.3, 55.9, 84.4 and 84.4 % for T. durum Desf., T. turgidum L., T. aethiopicum Jakubz., T. polonicum L. and T. dicoccon Schrank, respectively.  相似文献   

19.
Boxwoods (Buxus L., Buxaceae) are popular woody landscape shrubs grown for their diverse forms and broad-leaved evergreen foliage. We used genic simple sequence repeat (genic-SSR) markers to assess genetic diversity and relatedness of 275 accessions from the National Boxwood Collection at the U.S. National Arboretum. Flow cytometry was conducted to determine the relative ploidy of each accession. Genic-SSR loci were highly variable among the accessions, detecting an average of 6.7 alleles per locus based on 17 primer pairs. Data were analyzed with a distance matrix based on Jaccard’s similarity index, followed by Unweighted Pair Group Method with Arithmetic Mean clustering. Two major clusters were identified, with four subclusters consisting of individual accessions from B. balearica Lam., B. bodinieri Lévl., B. harlandii Hance, B. microphylla Siebold et Zuccarini, B. sempervirens L., B. sinica (Rehd. et Wils.) M. Cheng, and their putative interspecific hybrids. The accessions generally clustered by cultivar, provenance, or species. Clustering within each group typically reflected breeding pedigrees, when known, and the clusters were supported by bootstrap results. This information will be used for breeding programs and collection management, and for identifying possible sources of disease tolerance for boxwood blight and other diseases and pests.  相似文献   

20.
Jatropha spp. from Mexico includes high species richness and endemism; five species inhabit in the Tehuacan-Cuicatlan Biosphere Reserve (TCBR), and they are important resources as food, medicine and biofuel. The assessment of morphological and agronomic characteristics is essential to identify, use and maintain plant genetic resources. Given the lack of information on the morphological variability of Jatropha species in relation to environment, the objective was to analyze the influence of physiographic, climatic, and anthropogenic factors in the morphological variability of the species: Jatropha neopauciflora and J. rzedowskii, both not-endangered; J. oaxacana, special protection; J. ciliata and J. rufescens, both endangered in the Reserve. Twelve quantitative morphological variables were measured in 24 populations of these species; 14 environmental variables were registered, and the disturbance index in the sites was estimated. The information was analyzed with Principal Components Analysis (PCA), Cluster Analysis and Canonical Correspondence Analysis (CCA). PCA detected interspecific variation: J. ciliata and J. rufescens have longer and broader leaves and longer flowers, while the other three species have smaller leaves and flowers. J. oaxacana population has intermediate size of leaves, fruits and seeds, compared with those of J. neopauciflora and J. rzedowskii. CCA detected intra-specific variation among the populations of J. neopauciflora and J. rzedowskii, which were separated in two groups due to fruit and seed size. Axis 1 of CCA correlated positively with altitude and annual temperature range, and negatively with mean annual temperature; at the intra-specific level, both species are adapted to variations of temperature and altitude.  相似文献   

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