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1.
Expeditions were conducted in the Czech Republic, Germany, the Netherlands and United Kingdom in 2001 (partly 1998) to study Lactuca serriola L. (prickly lettuce, compass plant) geographic distribution, ecology, habitat characteristics and occurrence of diseases and pests on this species. During these missions the seed material of L. serriola L. was collected in an east–west transect of these four countries. The European transect where seeds were collected and field observations were made represents a relatively large area between 2°34′50′′ W–17°32′46′′ E and 47°40′42′′–54°04′19′′ N. The seed material was used for regeneration, inclusion in the national genetic resources collections of individual countries and for research purposes in follow-up studies. During the missions, 50 locations with occurrence of L. serriola L. were visited (16 in Czech Republic and Germany, 10 in UK and 8 in the Netherlands). Individual seed lots of sixteen different plants were collected at each location (L. serriola L. population). Thus, in total 800 seed samples were collected. In Czech Republic and Germany L. serriola L. f. serriola dominated in all observed populations, in the Netherlands both f. serriola and f. integrifolia occurred in pure or mixed stands, whereas in the United Kingdom L. serriola L. f. integrifolia (S.F. Gray) S.D. Prince et R.N. Carter was dominant. L. serriola L. was recorded at various altitudes (−4 to 410 m), different habitats (ditches, along roads, fields and field margins, ruderal places, pavements and parking sites, fallow fields), individual populations varied substantially in size (20 to >1000 plants), area covered (25–10,000 m2), and the structure and character of associated plant communities. Natural infections by downy mildew (Bremia lactucae Regel) and powdery mildew (Golovinomyces cichoracearum (DC.) V.P. Gelyuta) were observed in some populations. B. lactucae Regel was recorded only in Czech Republic, G. cichoracearum (DC.) V.P. Gelyuta was more common in continental Europe. General and specific aspects of L. serriola L. geographic distribution and ecology are discussed.  相似文献   

2.
A total of 1027 genotypes of wild Lactuca spp. (L. serriola, L. saligna, and L. aculeata), originating from Israel, Jordan, East Turkey, Armenia, Kazakhstan, China, and various other countries in Europe were screened for resistance to the lettuce downy mildew (Bremia lactucae Regel). The genotypes of L. serriola (N = 962); L. saligna (N = 43); and L. aculeata (N = 22) were tested at the seedling stage with two isolates of B. lactucae (race Bl-21 and Isr-74) isolated from cultivated lettuce in Italy and Israel, respectively. Altogether, the isolates possess virulence against 17 out of 20 Dm genes/R-factors composing the established differential set of lettuce lines/varieties. They could therefore be used for preliminary detection of the presence of new resistance factors. A total of 83 and three genotypes of L. serriola and L. saligna, respectively, were resistant to infection by each of the two isolates alone as well as to the infection by a mix of the two isolates. These genotypes probably carry previously unknown resistance, and therefore could be suitable for exploitation by breeders and further detailed research. The wild progenitor of lettuce, L. serriola, and related species harbor significant untapped genetic resources for lettuce improvement.  相似文献   

3.
During 2002, 2004, 2006 and 2008, trips were undertaken in the United States and Canada by members of the Department of Botany, Palacky University in Olomouc (Czech Republic) to record distributions and sample the diversity of wild and weedy Lactuca species. In that period, 16 states in the USA (Arizona, California, Colorado, Idaho, Iowa, Minnesota, Montana, Nevada, New York, North Carolina, Oregon, South Dakota, Utah, Washington, Wisconsin, Wyoming) and two provinces in Canada (Ontario, Quebec) were visited. Seven wild and weedy Lactuca species (L. serriola, L. saligna, L. virosa, L. canadensis, L. biennis, L. floridana, L. ludoviciana), an interspecific hybrid (L. canadensis?×?L. ludoviciana), and an undetermined Lactuca species were recorded, and 343 seed samples were collected from 200 locations. The largest number of wild Lactuca species that we observed was recorded in Iowa, and the largest number of samples was collected in California. The most common habitats of weedy species (L. serriola, L. saligna and L. virosa) were along transport corridors, such as roadsides, road ditches, parking sites and petrol stations, grassy slopes and ruderal places. The most frequent species was L. serriola, an Old World introduction, which we observed in all states and provinces visited, except for New York, and in broad range of elevations (up to 2,358?m a.s.l.). Lactuca saligna was recorded only one time in Salinas, California. Lactuca virosa was found repeatedly in Washington State along the road to the Mt. St. Helens and in Redwoods, California. Native North American taxa (L. canadensis, L. floridana, L. ludoviciana) were recorded only in Iowa. Lactuca biennis was found only in Canada in the southern part of Quebec. Records of diseases and pests showed only occasional occurrences of downy mildew (Bremia lactucae) and powdery mildew (Golovinomyces cichoracearum). Most plant-disease findings were made in Canada. Results of these efforts enrich our knowledge of the distribution, ecogeography and ecobiology of Lactuca species occurring spontaneously in North America. Seed collections (accessions) will be conserved in the working collection of the genebank at Palacky University to support future research in ecogeography, ecobiology, resistance and genetic polymorphisms, and to enrich of germplasm diversity available for lettuce breeding.  相似文献   

4.
Summary The 99 accessions of seven wild Lactuca species (L. serriola, L. saligna, L. virosa, L. viminea, L. perennis, L. tenerrima, L. tatarica) and Mycelis muralis (syn. L. muralis) were tested for natural infection of Erysiphe cichoracearum L. serriola accessions were highly susceptible. L. saligna showed highly variable levels of resistance. Other Lactuca species were mostly resistant or only moderately susceptible.  相似文献   

5.
A total of 1,383 accessions of wild barley (Hordeum vulgare ssp. spontaneum) held in the USDA-National Small Grains Collection, Aberdeen were screened for resistance to powdery mildew (Blumeria graminis f. sp. hordei) in the Czech Republic. They were subsequently tested at the seedling stage for reaction to selected powdery mildew pathotypes and simultaneously for their adult plant resistance in the field. One hundred and twenty-three accessions exhibited resistance to 22 pathotypes in the greenhouse tests (reaction type 2–3 or lower) as well as resistance to the natural population of this pathogen in the field in the Czech Republic during at least 2-year testing. These accessions represent large amount of promising sources in breeding barley for resistance to powdery mildew.  相似文献   

6.
The spread of the genus Lactuca worldwide includes 16 species in Europe, 51 in Asia, 43 in Africa and 12 in America (mostly North American subcontinent). Natural distributions of Lactuca spp. are compared with the representation of wild Lactuca spp. in world genebank collections as recently summarized in the International Lactuca database (ILDB). A total of 27 wild Lactuca species are reported in world genebank collections in the ILDB, however, due to incorrect taxonomic determination the real number of species is lower. The substantial part (92%) of the collections is represented only by three species (L. serriola, L. saligna, L. virosa) and from a geographic viewpoint they are mostly European in origin. The autochthonous species originating from other continents (Asia, Africa, America), which form c. 83% of known Lactuca spp. richness, are very poorly represented in collections (only c. 3%). The majority of accessions originate from Europe (59%) and Asia (37%), nevertheless the whole area of natural distribution is not well covered. An extremely low number of accessions is available from Africa and America (2% each). Thus, the global biodiversity of Lactuca spp. germplasm is represented very poorly and is biased in genebank collections. For future studies of taxonomy, phytogeography, ecology, phylogenetic relationships, genetic diversity, inter- and intra-population structure, resistance research and practical breeding exploitation of wild Lactuca spp. germplasm, plant material from a wider ecogeographic distribution must be collected and introduced into genebank collections more intensively.  相似文献   

7.
In spite of reports to the contrary, an analysis of 206 recent records for the years 1952 to 1982 shows that the medicinal leech Hirudo medicinalis Linnaeus is still present at one or more localities in 23 European countries (Albania, Austria, Britain, Bulgaria, Czechoslovakia, Denmark, Finland, France, German Democratic Republic, German Federal Republic, Greece, Hungary, Italy, Luxembourg, Netherlands, Norway, Poland, Rumania, Spain, Sweden, Switzerland, USSR and Yugoslavia). Its status is uncertain in Belgium, Portugal and European Turkey. It has disappeared from some localities in Britain but has been recently recorded at several others. It never occurred naturally in Iceland. Ireland is the only European country in which it once occurred but is now absent.  相似文献   

8.
Summary Patterns of achene proteins of L. sativa cultivars are mutually compared and compared with L. saligna, L. serriola and L. virosa. L. virosa and L. saligna are easy to identify and are characterized by typical banding patterns. L. sativa and L. serriola share the same banding pattern. They differ clearly from L. saligna and L. virosa. L. sativa and L. serriola are closely related (in terms of similarity), they form a common genepool and L. serriola is involved in the domestication process of L. sativa. Cultivar identification was not possible with the SDS-PAGE method.  相似文献   

9.
Exploitation of wild gene pool for breeding is a common practice in an increasing number of cultivated plants. The cultivated lentil could not attain the substantial improvement in the yield potential due to loss of genes for higher productivity and lack of resistance against biotic and abiotic stresses. The absence of evaluation data of wild lentils for characters of economic importance, besides biotic and abiotic stresses, is one of the constraints in their use in lentil breeding programme. In the present study, 70 wild accessions from four wild Lens subsp./sp. (L. culinaris subsp. orientalis, L. odomensis, L. ervoides and L. nigricans) along with 3 checks (Precoz, PL-406 and PL-639) were evaluated for phenological and agro-morphological characters, for their reaction to three fungal diseases (wilt, powdery mildew and rust) and screened for tolerance to moisture stress. The wild accessions showed higher performance for branches/plant as compared to cultivated genotypes. Similarly, a few accessions of L. culinaris subsp. orientalis were earlier to flower and had higher seeds and seed yield/plant as compared to cultivated lentil. However, some were comparable with cultivated genotypes for flowers/peduncle, peduncle length and plant height. The mean performance for flowers per peduncle, leaflets per leaf, plant height, seeds and seed yield per plant increased, while decreased for days to flowering and maturity, and branches per plant during the evolution of cultivated lentil from the wild Lens taxa. Of Lens taxa, L. nigricans had the maximum resistant accessions for biotic and tolerance to abiotic stresses. The valuable variation existing among wild accessions can be exploited following introgression with cultivated lentils. It will help in the flow of useful genes from wild to cultivated lentil for generating wide spectrum of variability and its subsequent use in genetic restructuring of lentil.  相似文献   

10.
Downy mildew (Peronospora viciae (Berk) de Bary) is an important disease of vetches (Vicia spp.) in the Mediterranean Region. Narbon and common vetch germplasm accessions originating from different countries, and advanced breeding narbon vetch genotypes, were evaluated for reaction to downy mildew for two seasons under field conditions. In narbon vetch, there were resistant sources from both germplasm accessions and advanced genotypes. From the germplasm accessions, 25 accessions were resistant while from the advanced breeding genotypes, 10 had resistance, with 2–3 ratings. In common vetch, many accessions were highly resistant to downy mildew. These were widely distributed in different countries, mainly Turkey, Italy, Syria and Iran. In general, common vetch had higher sources of resistance than the narbon vetch accessions. These new sources of resistance to downy mildew will be incorporated into the forage legume improvement project in a continuous effort to identify cultivars suitable for replacing fallow in the cereal-based cropping systems.  相似文献   

11.
One hundred and twenty-one of 123 previously detected new sources of wild barley (Hordeum vulgare ssp. spontaneum) resistant to powdery mildew (Blumeria graminis f. sp. hordei), and originating from Mediterranean area, and 20 standards were tested at the seedling stage for reaction to 38 selected Israeli powdery mildew isolates. The obtained resistance spectrum (a set of resistant and susceptible reactions) of each accession was divided into triplets and converted to octal numbers. This concentrates information on the resistance phenotype of each accession and makes their comparison much easier. One hundred and thirty-four different resistance spectra were determined. No compatible reaction was found in standards possessing genes mlo and Mlhb2 and in the accession PI 466634. The results demonstrate large diversity in new resistance sources, their distinction from the sources described till now as well as diversity in powdery mildew resistance of wild barley in the Mediterranean area. The results facilitate more effective further studies of such a large set of new resistance sources, and contribute to speeding up their use in barley breeding.  相似文献   

12.
The introduction of the American eastern grey squirrel (Sciurus carolinensis) in Europe is causing a dramatic decline of the native European red squirrel (Sciurus vulgaris), due to competition. We used spatially explicit population dynamics models to illustrate the potential expansion of the grey squirrel from Italy, the only continental country with the species, into neighbouring countries. Simulations started with the known grey squirrel distributions in 1996 and modelled the spread for the next 100 years in two different scenarios. One “best case” in which a random seed crop pattern of poor, good and mast seed crops was simulated with concomitant effects on squirrel fecundity and mortality and one “worst case” scenario in which poor years were not included. In the best case scenario, it will take 30-40 years for grey squirrels to start invading the Alps and about 70-75 years to cross the border between Italy and France. First populations in Switzerland are predicted in 2051-2066. In the worst case scenario, the spread will be significantly faster: the species is predicted to reach France in 2026-2031 and Switzerland in 2031-2041. Removing two of the three populations of grey squirrel will likely postpone the invasion of Switzerland but not of France. Large areas of Europe contain potentially good habitat for grey squirrels, and expansion from Italy, to France, Switzerland and belong to most of Eurasia is simply a matter of time. This will represent a serious risk for the conservation of the native red squirrel and will have implications for national forest operations. However, a European policy towards introduced species is still lacking. There is therefore a need for a co-ordinated European approach to the management of the grey squirrel and other introduced species.  相似文献   

13.
Thirteen landraces of cowpea (Vigna unguiculata (L.) Walp. subsp. unguiculata cv. gr. Unguiculata) have been morphologically and agronomically characterised as part of a plan for safeguarding and protecting plant biodiversity typical of Lake Trasimeno (Umbria, central Italy). Sixty plants per accession were scored for plant vigour, growth habit, flower colour, days to flowering, days to first mature pod, pod length, total number of pods produced, seed colour pattern, 100 seed weight, total seed yield and virus susceptibility. With the exception of vigour and growth habit, all landraces appeared to be well differentiated from one another for all the characters considered. Strategies and problems related to their in situ conservation are discussed.  相似文献   

14.
A collection of wild artichokes (Cynara cardunculus L. var. sylvestris (Lam.) Fiori) was conducted in south Italy. The distribution of the wild populations was not even all over the explored territory, from the coastline to the inner mountains, and in some areas wild artichokes were completely absent. A certain level of morphological variation for height and habit of plants, size and shape of capitula, length, shape, and position of bracteal spines, was observed. It has been noticed that picking capitula from the wild for human consumption is a common habit in southern Italy and Sicily. Historical data and etnobotanic inference suggest the idea that the artichoke could have been domesticated in south Italy, and Sicily in particular, and was spread by the Arabs to other regions of the Mediterranean Basin.  相似文献   

15.
After 23 years of war, current information about the biodiversity of crops in the Hindukush mountains of Afghanistan is scarce. This study aimed at assessing the genetic composition of farmers wheat (Triticum spp.) populations through a survey of 21 randomly chosen cereal fields on both sides of the Panjsher river in the upper Panjsher valley of Northern Afghanistan. A stratified sampling of wheat heads according to morphological differences was followed by estimates of field size and grain yield and a formal interview with the landowner about the cropping sequence and the inputs used. About 75% of the cereal fields were cropped in rotation systems with faba bean (Vicia faba L.), barley (Hordeum vulgare L.), potato (Solanum tuberosum L.), maize (Zea mays L.) or fallow. Manure application at between 2.3 and 5.3 t ha−1 was the major source of nutrient inputs at grain yield levels between 1.2 and 4.7 t ha−1. The morphological characterization of the collection revealed 19 taxonomically different varieties of bread wheat (Triticum aestivum L.) but also barley and triticale (Triticosecale Wittm.) grown in mixtures. Populations within one field consisted of up to seven botanical wheat varieties. Farmers did not differentiate between morphological differences within such mixtures but identified their populations instead according to grain color, cooking properties and resistance to mildew and frost. Triticum aestivum var. subferrugineum was the most widespread wheat variety and no effects of altitude on biodiversity of wheat was noted across the transect. Particularly interesting was the occurrence of T. aestivum var. subferrugininflatum and var. subgraecinflatum which so far have only been reported from Mongolia. The finding of triticale indicated the active seed exchange with lowland or long-distance seed sources.  相似文献   

16.
Twenty four barley lines derived from the F 7generation of crosses between two winter barley cultivars and different accessions of Hordeum spontaneum Koch collected in Israel were tested against a set of ten European and five Israeli powdery mildew cultures, possessing virulence genes which completely match the spectrum of known mildew resistance genes. The comparison of reaction patterns justified the conclusion that new genes for resistance have been conferred from H. spontaneum which also differ from genes previously identified in other wild barley accessions from Israel. Participation in the expression of the resistance reaction of one of the two barley cultivars used in the development of the lines is well documented in some cases. The majority of the lines was found to be highly resistant against all or almost all European isolates, while various kinds of reactions were observed against the Israeli cultures. The effective transfer of novel mildew resistance from H. spontaneum into winter barley confirms similar results with spring barley, indicating natural wild barley populations in Israel as a significant gene pool for yet unexploited mildew resistance in barley.  相似文献   

17.
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18.
In order to identify key adaptive traits which affect productivity in Mediterranean grain and forage legumes and simultaneously determine the agricultural potential of a wide range of Vicia species, germplasm collected from the wild throughout the eastern Mediterranean was grown under semi-arid conditions in Tel Hadya, Syria (313 mm growing season rainfall). These included species currently in use in Mediterranean agriculture, such as V. sativa L., as well as those more widely used in the past-such as V. ervilia L., but also a broad selection from Section Narbonensis (B. Fedtsch. ex Radzhi) Maxted, including V. narbonensis L, V. johannis Tamamsch., V. hyaeniscyamus Mout., V. serratifolia Jacq., and V. kalakhensis Khattab et al. V. faba, a near relative of the taxa in Section Narbonensis, was included as a domesticated control. Where applicable, a representative range of subspecies was used. Accessions were chosen from a wide range of habitats in terms of latitude (31.02–40.72 decimalo), longitude (27.1–43.17 decimalo), altitude (20–1510 m), rainfall (180–1700 mm/yr) and soil depth (5–50 cm) in order to maximise diversity within species. Agricultural potential was determined by measuring seed, hay and biological yield, as well as agronomic traits such as harvest index, standing crop height, and seed size. The comparative influence of phenology and key agronomic traits such as plant habit and seed size on productivity varied tremendously between species, depending on their reproductive strategies. In V. sativa and V. ervilia, the smaller seed species which rely on long vegetative phases and growing seasons to accumulate sufficient biomass to set seed, and in which there was comparatively little agronomic variation, phenology had a large impact on yield. In early emerging taxa such as V. ervilia and V. s. subsp. sativa, with built-in long vegetative phases and growing seasons, seed yield was negatively correlated with flower ing (r = –0.86 to –0.88), whereas the opposite was the case for later emerging taxa such as V. s. subsp. nigra (L.) Ehrh. (r = 0.95). Within V. narbonensis and relatives, the larger seeded Vicia species which rely on more conservative reproductive strategies where high seedling vigour associated with large seeds enables the species to enter reproductive phases relatively early, phenology had a much smaller impact on yield than did variation of key traits such as seed weight, plant habit and pod shattering. Among the undomesticated germplasm harvest indices ranged from 0.09–0.31, hay yields from 0.1–3.4 t/ha, seed yield from 0–2.0 t/ha, and dry matter at maturity from 1.6–6.5 t/ha. Sub-specific taxonomy was crucial in determining agronomic potential. V. narbonensis var. aegyptiaca Kornhuber ex Asch. et Schweinf. showed the most potential, combining an upright habit, large seeds (212 mg) and tendency to retain intact pods after maturity, with the highest yield, harvest index and crop height of all the wild Vicia species. V. sativa subsp. sativa, V. ervilia and V. narbonensis var. narbonensis were less productive, but still showed agricultural potential. The smaller seeded V. narbonensis, var. affinis, var. jordanica H. Schäf. and var. salmonea (Mout.) H. Schäf., and their close relatives V. johannis, V. hyaeniscyamus, V. serratifolia and V. kalakhensis have little to offer Mediterranean agriculture on the basis of poor agronomy.  相似文献   

19.
Arable fields of 10 organic farms from different locations in The Netherlands were sampled in three subsequent years. The soil samples were analysed for disease suppressiveness against Rhizoctonia solani AG2.2IIIB in sugar beet, Streptomyces scabies in radish and Verticillium longisporum in oilseed rape. In addition, a variety of microbial, chemical and physical soil characteristics were assessed. All data were correlated by multiple regression and multivariate analyses with the objective to find correlations between soil suppressiveness and biotic or abiotic soil characteristics. Significant differences in soil suppressiveness were found between the fields for all three diseases. Multiple regression indicated a significant correlation between suppressiveness against Rhizoctonia and the number of antagonistic Lysobacter spp., as well as with % active fungi and bacterial diversity. Grass-clover stimulated Rhizoctonia suppression as well as the presence of antagonistic Lysobacter spp. (mainly L. antibioticus and L. gummosus) in clay soils. Streptomyces suppression correlated with the number of antagonistic Streptomyces spp., % of active fungi and bacterial population size. The presence of antagonistic Streptomyces spp. correlated with a high fungal/bacterial biomass ratio. Verticillium suppression was only measured in 2004 and 2005, due to the inconsistent suppressiveness along the years. Nevertheless, a significant correlation with pH, potential nitrogen mineralization and bacterial biomass was found. Bacterial and fungal PCR-denaturing gel electrophoresis fingerprinting of bacterial and fungal communities, in general, did not significantly correlate with disease suppression. Highly significant explanatory factors of the composition of the dominating bacterial and fungal populations were % lutum, pH, C/N quotient, biomass and growth rate of bacteria. Additionally, the % of organic matter and years of organic farming were explaining significantly the composition of the bacterial population.Thus, significant correlations between several soil characteristics and suppressiveness of different soil-borne pathogens were found. For two of the three pathogens, suppression correlated with biotic soil characteristics combined with the presence of specific bacterial antagonists. Probably the soil suppressiveness measured in the organic fields is a combined effect of general and specific disease suppression.  相似文献   

20.
The common potato, Solanum tuberosum spp. tuberosum (tbr), is a tetraploid species with a narrow genetic base, but with a large number of related species that harbor great genetic diversity for numerous characters of agronomic interest. S. kurtzianum (ktz) and S. ruiz-lealii (rzl) are wild diploid relatives with potential resistance to adverse biotic and abiotic factors. To evaluate if this wild germplasm can be incorporated by conventional crosses into the tbr gene pool, pollen-pistil compatibility relations and seed set in interspecific crosses with tbr were investigated. In 4x tbr × 2x ktz crosses and the reciprocals, 89% and 52.2% of genotypic combinations (respectively) were compatible at the pollen-pistil level. Seeds were obtained from some genotypic combinations in both directions of the cross, suggesting that functional 2n gametes might be produced by particular ktz genotypes. In 2x rzl × 4x tbr crosses and their reciprocals, 35% and 11.7% (respectively) of the genotypic combinations were compatible at the pollen-pistil level, but no seeds were obtained. These results indicate that the reproductive isolation between 4x tbr and 2x ktz is incomplete, and that gene exchange between them is feasible. Moreover, further studies will have to be carried out with rzl to ascertain its crossability with 4x tbr.  相似文献   

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