首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 906 毫秒
1.
During a national Swedish collection mission of vegetable varieties conserved ‘on farm’ more than 70 pea accessions were obtained, many of which had been grown locally for more than 100 years. In spite of a likely origin in the multitude of obsolete commercial pea varieties available on the Swedish seed market in the nineteenth century, the rediscovered local cultivars have lost their original names and cultivar identity while being maintained ‘on farm’. To analyze genetic diversity in the repatriated material, 20 accessions were genotyped with twelve SSR markers and compared with 15 obsolete cultivars kept in genebanks and 13 cultivars preserved as non-viable seeds collected in 1877–1918. Most of the local cultivars were genetically distinct from each other, and in only a few cases could a possible origin in a tested obsolete cultivar be suggested. These results reflect the wide diversity of pea cultivars present in Sweden during the nineteenth century. Both between and within accession genetic diversity was larger among the historical samples of obsolete cultivars compared to local cultivars and cultivars preserved in genebanks, indicating genetic erosion over time both in genebanks and during conservation ‘on farm’. The constraints on identifying and verifying historical cultivars using genetic markers are discussed.  相似文献   

2.
The continued cultivation of Lupinus pilosus L. as an endemic coffee substitute in the mountain village of Altrei, South Tyrol, located in the Val di Fiemme/Fleimstal valley ca. 24 km south of Bolzano/Bozen, since the middle of the nineteenth century is demonstrable. Former reports of cultivation of Lupinus cosentinii Guss. and L. varius auct., non L. for this purpose in Tyrol could refer to L. pilosus as well. The cultural history of the rare crop is summarized up to its recent revival.  相似文献   

3.
The first cultivated wheat, cultivated einkorn (Triticum monococcum L. subsp. monococcum), was domesticated in South-East Turkey during the Pre-Pottery Neolithic period. It then spread to the Middle-East, the Balkans and Caucasus, Turkmenistan, Central and Mediterranean Europe, North-Africa, and finally to Western and Northern Europe. In all these regions, it played an important role in the development of agriculture and was cultivated for several centuries before being replaced by free-threshing wheats. Today, cultivated einkorn is only present in isolated, mountainous areas of a few countries. However, there is renewed interest for this crop due to the nutritional qualities of its grain, its adaptation to low-input agriculture and high level of resistance to pests and diseases that represent advantages for organic farming. Cultivated einkorn is also a valuable reservoir of genes for wheat improvement. Its utilization, limited by its hulledness, low yield and especially by a poor knowledge of its diversity and its low crossability with bread and durum wheat, is expected to increase in the future, particularly with the need for wheat breeding to face newly emerging diseases through the use of genetic resistances. Considering these perspectives, the present review attempts to analyse the current and historical importance of einkorn cultivation and utilization in wheat breeding, tracing back to its origin and diffusion. The main traits of resistance to pest and diseases, and the nutritional qualities and technological characteristics of the grain are described. Einkorn genetic resources diversity exploration is reviewed and successful examples of introgression of useful einkorn traits into cultivated wheat are reported. Lastly, perspectives of einkorn cultivation development in low-input agriculture and use for wheat enhancement are discussed.  相似文献   

4.
Germination of wild and managed populations of columnar cacti was compared to analyze differences associated to management intensity. The species studied: Polaskia chende, Escontria chiotilla, Myrtillocactus schenckii, Polaskia chichipe, and Stenocereus pruinosus are in a gradient from lower to higher management intensity, respectively. Within each species wild, silvicultural, and cultivated populations also represent a gradient from lower to higher management intensity. We hypothesized that seeds of plants under higher management intensity would require more water to germinate than others since managed environments are relatively wetter than unmanaged environments. Such pattern could be visualized within and among species according to management intensity. We tested germination of seeds from different populations of the different species to the water potentials: 0.0, ?0.2, ?0.4, ?0.6, ?0.8, and ?1.0 MPa. In all species studied seeds of managed populations had significantly more mass than seeds from wild populations. Each species had different susceptibility to water availability decrease, which could be related to particular adaptations to drought resistance. Stenocereus pruinosus and Polaskia chende were the most and least susceptible species, respectively. In control treatments of all species, seeds of managed populations had higher germination rate than seeds from wild populations, but when water availability decreased the pattern was the contrary. Our results suggest that artificial selection for larger fruits and heavier seeds in plants established in wetter environments have affected germination patterns. Although species have particular critical points of water availability for germination, differences in germination patterns are more pronounced according to management and artificial selection intensity.  相似文献   

5.
Diospyros kaki Thunb. originated in Eastern Asia, as evidenced of its culture in China as early as several centuries B.C. In the seventh century, persimmon was introduced to Japan and later, in the fourteenth century to Korea. There is no information about persimmon culture in Europe until the seventeenth century, with the spread over the world occurring in the eighteenth century. The genus Diospyros contains more than 400 species, with levels of ploidy ranging from diploid (2n = 2x = 30) up to nonaploid (2n = 9x = 135). The primary economic crop species is Diospyros kaki Thunb., which is mainly hexaploid (2n = 6x = 90) and includes hundreds of cultivars. Although a relatively recent introduction in Europe, the species has adapted well, and the genetic diversity have been expanded with culture and selection for the past 200 years in the Mediterranean basin. These locally adapted cultivars were evaluated with cultivars from Asian origin in a germplasm collection established at IVIA in Valencia, Spain. In this paper 27 cultivars from the IVIA collection were studied by multivariate analysis, and 37 variables were analyzed using a Principal Components Analysis and cluster analysis following the method UPGMA. Studies on correlations and significance among variables identified the most relevant ones, and thus provided information for a future core collection.  相似文献   

6.
Isatis tinctoria L. is a biennial species which was cultivated in Europe until the 18th century to produce indigo, a pigment used for dyestuffs. Today there is renewed interest in this ancient crop because of a market demand for natural dyes. Cultivation of the species appears to be particularly suitable for marginal areas. Information about the evolutionary and genetic patterns of I. tinctoria is needed if varieties or to be developed in future breeding programs. The aim of this study was to assess the genetic variation and similarity levels among and within natural populations of I. tinctoria from Europe and central Asia. Fifteen populations were used to carry out the genetic analyses with AFLP and SAMPL molecular markers. Data collected were analysed by the UPGMA method and were used to perform AMOVA. The results are consistent with the hypothesis that the crop originated in an eastern centre of origin and moved westward giving rise to a gene pool that is quite different from the original. The wide within-population variation revealed by this study suggests that effective breeding work to develop varieties suitable for marginal environments can be carried out easily.  相似文献   

7.
Phyllostomid bat diversity in a variegated coffee landscape   总被引：1，自引：0，他引：1  
We examined bat diversity at two different spatial scales: habitat and matrix, in the Quindío coffee region in Colombia. Habitats were: forest, shaded coffee and associated coffee; and matrices were: associated coffee (M1) and shaded coffee (M2). Three sampling sites from each type of habitat were located at each matrix. The forest areas of the Quindío region are severely fragmented and less structurally complex than coffee patches. The shaded coffee habitat had patches that were larger and more complex. In spite of limited patch size and lower complexity, the forest remnants were those with greatest species richness and demonstrated clear similarities even between the two matrices. This was not observed in coffee plantations, neither in associated coffee nor shaded coffee. On the landscape scale, M2 showed lower β diversity and greater edge density (ED) than M1. This fact explains that greater connectivity between different habitats exists in M2 than in M1. Our results suggest that production and conservation are compatible, as maintenance of forest remnants in a mosaic structure by landowners of the vegetation is sufficient to conserve phyllostomid bats at landscape level.  相似文献   

8.
American ginseng (Panax quinquefolius) is a native North American medicinal plant that is becoming increasingly vulnerable despite government harvest restrictions. To better understand the genetic diversity and gene flow of American ginseng, we studied RAPD variation in cultivated and wild populations. Classical and Bayesian analogues of genetic diversity statistics were estimated in seven wild and two cultivated populations. The wild populations were more highly structured (G stβ  = 0.41) than the cultivated populations (G stβ  = 0.24). The genetic diversity within populations ranged from H eβ  = 0.05 to 0.38. Based on genetic pairwise distances, six of the wild populations clustered with the locally-derived cultivated population, while one wild population was more similar to the non-local cultivated population than the local populations. This wild population was highly diverse (P = 1.0; U = 1.0) suggesting that it was supplemented from exotic seed. A set of eight RAPD markers was identified that differentiated plants of local and non-local origin. As a conservation strategy, we recommend that regional gene banks be established based on molecular and geographic diversity to preserve the locally adapted germplasm. These regional gene banks would serve as a conservation tool and also provide a source of genes for genetic improvement of cultivated ginseng.  相似文献   

9.
Goldenseal (Hydrastis canadensis L.) is a medicinal plant valued for the treatment of sore eyes and mouths. Although cultivation of the plant has helped meet growing demand, goldenseal is still considered a threatened or endangered species throughout much of its range in North America. In an effort to assess possible conservation strategies for goldenseal genetic resources, levels of genetic diversity within and among cultivated and wild populations were quantified. RAPD analysis was used to examine six cultivated and 11 wild populations sampled from North Carolina, Ohio, Pennsylvania, and West Virginia. The average percentage of polymorphic bands in cultivated and wild populations was low (16.8 and 15.5 %, respectively), and geographic range did not predict the level of genetic diversity. Most of the genetic variation (81.2 %) was within populations; only 3.6 % was partitioned between cultivated and wild populations. Our results differed from a previous study which concluded that genetic differences were greater among than within populations. The results of the current study indicate that, although goldenseal grows clonally and in dense patches, a mixed mating system in which both selfing and outcrossing occur is also operating. We therefore suggest that the ex situ conservation of individual plants within populations, chosen carefully to account for clonal propagation in situ, is an appropriate strategy for sustaining the genetic diversity of goldenseal.  相似文献   

10.
The genus Zanthoxylum, belonging to Rutaceae, has a long history of cultivation both for economic and chemical values in China. To effectively conserve and sustainably utilize this genus resource, a study on genetic diversity and relationships of Zanthoxylum germplasms was carried out by employing SRAP markers. We used 16 primer combinations to assess genetic variations and relationships among 175 accessions from eight cultivated provenances, including Shandong, Henan, Shanxi, Shaanxi, Gansu, Sichuan, Guizhou and Yunnan. A total of 145 clear repetitive and intense bands were yielded, and the percentage of polymorphic bands was 100 % for per primer combination, indicating a relatively high diversity among Zanthoxylum germplasms. From a geographic perspective, the highest genetic diversity level was observed within Guizhou provenance (N a  = 1.97, Ne = 1.52, H = 0.31, I = 0.46) while Henan provenance had the lowest genetic diversity (N a  = 1.68, Ne = 1.45, H = 0.25, I = 0.37). Based on AMOVA results, the abundant genetic variation was mainly caused by variation of intra-provenances (84.96 %), rather than among provenances (15.038 %). The results indicated low genetic differentiation (G st  = 0.133) and high gene flow (N m  = 3.2605) among provenances. The neighbor-joining tree revealed that the 175 accessions could be divided into four groups, and groupings indicated a divergence between the cultivated accessions of Zanthoxylum bungeanum Maxim. and Z. armatum DC. Moreover, three accessions of Z. piperitum DC. var. inerme without prickles introduced from Japan gathered one cluster. Cluster IV is composed of accessions of different geographical origin, including 11 wild species and 10 cultivated accessions of Z. bungeanum. The cluster analysis also reflected a relatively close relationship between the geographical origins and the classification of accessions in cluster I. Structure analysis indicated that collected Zanthoxylum accessions could be divided into two major groups. The information obtained from our research would benefit to make use of Zanthoxylum germplasms and assist the management of a Zanthoxylum germplasms collection.  相似文献   

11.
Local patterns of seed regeneration and trade that occur outside the formal breeding sector (seed exchange networks) can have a strong influence on the genetic diversity and evolution of traditional crop varieties. Despite this, little is known about the extent to which seed exchange networks influence gene flow and genetic structure in traditional crop varieties. Here we study barley (Hordeum vulgare subsp. vulgare) in rural communes of Northern Morocco in 2008 and 2009. We quantified seed regeneration and exchange by farmers within the seed exchange network using structured interviews. Using SSR markers, we also quantified the neutral genetic diversity and structure of a complex of traditional varieties referred to as Beldi that is managed in this exchange network. The majority of farmers (>88 %) report cultivating Beldi. Most seeds of Beldi (70–90 %) are maintained on-farm, while the remainder of seeds are obtained from local markets within the commune. Beldi has high genetic diversity and there is weak but significant genetic structure between communes (FST = 0.031). From SSR marker data there is evidence of a high level of gene flow between communes not reported in interviews. Seeds purchased in local markets likely represent seeds from a larger geographic region, leading to lower genetic structure among communes than expected based on the reported level of on-farm seed regeneration and local sourcing of seed. We discuss the implications of this seed exchange network for the conservation of traditional barley varieties in the study region.  相似文献   

12.
Helianthus tuberosus agg., an herbaceous perennial plant from the Asteraceae family, is native to North America and was introduced as a crop to Europe in the seventeenth century. The status of this plant has been rather controversial in the Carpathian Basin. This paper reviews its taxonomy, chorology, and ethnobotany in this region, using data obtained from herbarium specimens, ethnobotanical surveys performed in Transylvania, and data published earlier, documenting the invasive features of the plant since the beginning of the nineteenth century. Our results suggest that (1) Helianthus tuberosus agg. has been present in the Carpathian Basin from the nineteenth century, (2) its taxonomy is problematic since the first part of the nineteenth century; (3) ethnobotanical surveys confirmed that the plant’s tuber has been locally used mostly as a food in Transylvania, collected from cultivation. Overall, Helianthus tuberosus agg. is both a ‘blessing and a curse’ at the same time, it is a valuable crop with beneficial nutritional value, and also an environmentally dangerous invasive element for the diversity of the flora of the Carpathian Basin.  相似文献   

13.
Lima bean is a species cultivated broadly in the Americas and has been cultivated in the Caribbean for at least 500 years. In order to determine the genetic structure and diversity of Lima bean from the Caribbean, 50 landraces from Haiti, the Dominican Republic and Puerto Rico were collected and analyzed using 24 SSR markers. All landraces in this Caribbean collection were found to be of Middle-American descent. The genetic diversity (HE) was highest in the landraces from Puerto Rico and lowest in Haitian landraces. The observed proportion of heterozygotes (HO) was higher in the Haitian landraces and lowest in Puerto Rican landraces. Unweighted pair-group method with arithmetic averaging analysis showed that the landraces clustered into 3 clusters with all Haitian landraces grouping in one cluster. We also assessed the agro-morphological characteristics of the collection as well as the content of cyanogenic glucoside, linamarin, in leaves and dry seeds. Lima bean, which is a model crop for indirect plant defenses against herbivory, also possess linamarin as a source of direct plant defense. Upon tissue damage, linamarin is converted to toxic hydrogen cyanide. In our collection 44.6 % of the landraces had average seed HCN content ≤200 ppm which is the permitted level for Lima bean seed in the US. Our results also identified the landraces in this collection which have high linamarin levels in the leaves while having low levels in the seeds. Such landraces have the desirable combination of traits and will be the focus of our future plans for agronomic trait improvement though breeding.  相似文献   

14.
America’s date palm (Phoenix dactylifera L.) groves can be found from 36°N Lat. (USA) to 21°S Lat. (Chile) and from 63°W Long. (Venezuela) to 117°W Long. (USA), at elevations from sea level to 2,000 m (Colombia). However, successful production of ripe dates is possible only in the arid regions of Peru, Chile, Baja California (Mexico) and the southwestern USA. At present, the major extant palm groves of Spanish origin in the Americas are situated in Baja California, Mexico and Peru. A study of the origin and diversity of the date palms of Spain and the Americas revealed abundant historical documentation permitting a historical picture of the introduction of date palm to the Americas. It can also shed light on the areas of origin of the plant material involved. Dates arrived in the Americas very soon after European contact (1492), and in the early sixteenth century there were numerous date palms on the islands of the Caribbean and on the mainland, as evidenced by the chroniclers of the Indies. Date palms reached the coasts of Peru and Chile in the late sixteenth century, and in some places still produce edible dates. The date palm appears to have come later to California and Baja California, from the beginnings of the eighteenth century, and its cultivation was established and has continued in Baja California (Mexico) in oases near former Jesuit missions. Spain and the Barbary Coast (Morocco, Algeria and Tunisia) were the places of origin of seeds for the Americas; beginning in the late nineteenth century offshoots were introduced from Iraq and North African countries directly to the Americas, especially the USA.  相似文献   

15.
Dill (Anethum graveolens L.) leaf, seed and their essential oil are rich source of antioxidants. The plant is native in Southwest Asia and is cultivated in Europe, India and the United States. This study evaluated the genetic diversity structure of 135 accessions of A. graveolens from different continents, based on random amplified polymorphic DNA (RAPD) markers. The selected 10 RAPD primers generated a total of 142 highly reproducible bands, among which 89 were polymorphic. Percentage of polymorphism varied from 41.17 % (OPB20) to 92.85 % (OPB15) with an average of 77.74 %. A relatively high genetic diversity was detected among all the accessions with the Nei’s genetic diversity (H) values ranged from 0.346 (OPB07) to 0.444 (OPB18) with a mean of 0.401. When estimated for Shannon’s information index (I), it has ranged from 0.530 (OPB12) to 0.652 (OPB18), the mean was observed as 0.581. The respective values of H and I were found to be the highest value for primer OPB18. Cluster analysis of RAPD data using UPGMA algorithm based on Nei’s genetic similarity matrix placed the 135 accessions into two main clusters. Although a number of groups can be identified, the clusters show little to no association with the geographic origin of the material. The implication of the results of this study in developing a strategy for the conservation and breeding of dill germplasm are discussed.  相似文献   

16.
A major objective of this work is to elucidate the ancestry and genetic background of contemporary U.S. garden pea (Pisum sativum L. convar. medullare Alef.) cultivars used as cultivated vegetables. This is facilitated through pedigree analysis of 147 cultivars registered during the era from 1990 through 2010 by collecting data from U.S. Plant Variety Protection, U.S. utility patent, and journal publication. Proprietary breeding programs developed 141 cultivars and public programs six, with over half (82 of 147 cultivars) originating from the two (Seminis Vegetable Seeds, Inc. and Syngenta Seeds, Inc.) largest proprietary breeding programs. During this era, the semi-leafless (afila) trait was bred into cultivars to decrease lodging, and 43 % of the cultivars were afila. Registered cultivars were 86 % of determinate growth habit. Bi-parental breeding crosses were used in the development of 78 % of these cultivars. The lineages of the cultivars ‘Bolero’, ‘Spring’, ‘Genie’, and ‘Rally’ made large contributions to the genetic composition of this germplasm, ‘Bolero’ contributed 6.5 % (29 progeny), ‘Spring’ 6.4 % (29), ‘Genie’ 4.0 % (18), and ‘Rally’ 3.6 % (23) of the genes. The garden pea ancestor cultivar ‘Perfection’ fostered the most descendants (75) among the 147 cultivars of this era.  相似文献   

17.
Yam (Dioscorea spp.) is widely cultivated in China and many landraces are maintained by local farmers. However, there is little information available about their diversity and species identity. In this study, inter simple sequence repeat (ISSR) and sequence related amplified polymorphism (SRAP) techniques were used to assess genetic diversity within 21 yam landraces from seven cultivated populations. We observed high level of polymorphism among these landraces, specifically, 95.3 % for ISSR and 93.5 % for SRAP. Analysis of molecular variance revealed a significantly greater variation among the four yam species (40.39 %) and their populations (35.78 %) than within the populations (23.83 %). The unweighted pair group method arithmetic averages clusters and principal component analysis for 21 landraces formed four well-separated groups containing landraces of each of the four species, namely, Dioscorea opposita Thunb., Dioscorea alata L., Dioscorea persimilis Prain et Burkill, and Dioscorea fordii Prain et Burkill. The ISSR and SRAP primers were highly discriminatory among the 21 landraces; all 21 landraces could be easily differentiated using these primers. The average mean of gene flow (Nm = 0.1081) estimated from high genetic differentiation (Gst = 0.8222) suggested that gene flow among the populations was relatively restricted. The lack of genetic diversity within individual yam species suggests that it is critical to develop long-term strategies for enhancing genetic diversity within various yam species.  相似文献   

18.
Improved agronomic performance and nutritional profile are among the major objectives in pea breeding, but the narrow gene pool available in pea germplasm has slowed progress. Therefore, the objective of this work was to evaluate 169 diverse pea accessions from Eastern Europe, Western Europe, Australia and Canada for agronomic performance, Mycosphaerella blight resistance and nutritional profile under western Canadian growing conditions. In general, eastern European accessions required less days to flower, had higher protein, acid detergent fibre and neutral detergent fibre concentrations in the seeds, compared to western European and Canadian pea accessions, which had better lodging resistance, less days to maturity, higher grain yield and seed weight, greater resistance to Mycosphaerella blight and powdery mildew and higher starch concentration in the seeds. Significant correlations were observed between different traits. Principal component analysis revealed significant variation among traits with the first four principal components explaining 68 % of the total variation. The wide range of variation in agronomic performance, Mycosphaerella blight resistance and nutritional profile detected will provide useful parents for pea breeding.  相似文献   

19.
An experiment was carried out in a climate chamber to analyse if Bt-maize may cause particular changes in soils with different levels of microbial biomass and activity due to long-term management history. Among the soils selected, the ones managed organically for 30 years exhibited twice the microbial biomass and 2.6 times the dehydrogenase activity (DHA) of the soil from a field with long-term conventional maize monoculture. Soils were cultivated twice in a row with Bt-maize, its near-isogenic line and a conventional breeding line. We tested the hypotheses that (a) soil microbial biomass and activity are affected by the cultivation of Bt-maize and that (b) the influence of Bt-maize depends on the level of soil microbial biomass and activity. Shoot and root yield and shoot C-content of Bt-maize were higher than the ones of the near-isogenic line. DHA under Bt-maize was 6 % higher, and the metabolic quotient for CO2 (qCO2) was 9 % lower than under its near-isogenic line, giving some support to hypothesis (a). No significant interactions of the soils and the varieties used were found in this study, thus hypothesis (b) was not confirmed, and soils with different microbial biomass and activity appear to react in a similar way to the cultivation of Bt-maize.  相似文献   

20.
As the second species used for commercial coffee, evaluation of Coffea canephora Pierre ex Froehner population genetics is a challenging task for coffee breeding. This study examined the pattern of genetic variability and genetic relationships of cultivated and wild populations of C. canephora sampled across the Guineo-Congolese region of Africa and some improved populations maintained in field genebanks. A total of 293 individuals, sampled from 17 populations, were genotyped with 39 nuclear microsatellite markers. Genetic diversity and structure were investigated with both a model-based and a graphical approach; isolation by distance was also tested. Relationships between the diversity clusters are discussed with regard to differentiation due to several glacial refuges during the Last Glacial Maximum (LGM). High genetic diversity within C. canephora is confirmed with a mean number of alleles of 11.85 per marker, a mean gene diversity of 0.72 and a mean observed heterozygosity of 0.36. An overall structure of two main groups (Guinean and Congolese) subdivided in six subgroups (2 for the Guinean and 4 for the Congolese) was found, including one described for the first time in the Guinean group. A fine structure within the Guinean group was also newly detected. Genetic structure of C. canephora appears to be consistent with its geographic repartition at the continent scale. Structure of diversity was found in accordance with localizations of refuge zones during LGM and migration from this period. Results from this genetic structure study raise our capabilities to better manage and use the collections of genetics resources for breeding purposes. Those results will be used in future association studies to optimize the number of genotypes to be phenotyped.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号