Gegenwärtige Problematik und Richtungen der Blattlausparasitenforschung(Hymenoptera : Aphidiidae)     

Peter Starý 《Journal of pest science》1970,43(2):19-22

Ohne Zusammenfassung  相似文献   

Avena fatua L. subsp. fatua v. glabrata Peterm. subv. pseudo-basifixa Thell. as a source of crown rust resistance genes     

J. Šebesta  F. Kühn 《Euphytica》1990,50(1):51-55

Summary An accession of Avena fatua L. subsp. fatua v. glabrata Peterm. subv. pseudo-basifixa Thell. (A. fatua L. CS Sel. No. 1), collected in Czechoslovakia in 1971, was found to be resistant to a wide range of crown rust races. Analyses of crosses of this oat with cvs. Weikuss, Leanda, Mona, Rodney A, Rodney B, Rodney M, Dodge and K 316 indicated that the resistance of A. fatua CS Sel. No. 1 is conditioned by one recessive gene which is in interaction with one partially dominant gene with additive effect. The expression of rust reaction was affected by temperature. The crown rust resistance genes of A. fatua L. CS Sel. No. 1 were non-allelic with stem rust resistance genes Pg-2 (A) and Pg-4(B).  相似文献   

Variation in effective pollination rates in relation to the spatial and temporal distribution of pollen release in rejuvenated perennial ryegrass     

R. Van Treuren  P. J. Goossens  M. Ševčíková 《Euphytica》2006,147(3):367-382

Genebank accessions stored as seed populations require periodic rejuvenation in order to maintain sufficient numbers of viable seeds. During rejuvenation the genetic composition of accessions may be altered for a variety of reasons, of which variation in pollination rates between plants is the least understood. In the present study, a paternity exclusion analysis was performed on a rejuvenated accession of perennial ryegrass. In addition, flowering data of the 49 parental plants were collected during the flowering season. The aim of the study was to determine how accurate variation in pollination rates between plants can be predicted from data on the spatial and temporal distribution of pollen release. The parental population and a total of 551 offspring from 12 progeny arrays were genotyped by means of molecular analysis. Using 25 microsatellites, paternity was identified for 81.9% of the offspring, while remaining ambiguities were resolved by AFLP analysis, except in four cases. Within the total sample 9 cases of contamination were observed. Mating within the study population was clearly non-random, as 61.9% of the identified pollen donors were located within 1 m distance from the mother plant. Observed pollination rates were very well described by an inverse quadratic function of inter-plant distance between potential mating pairs. Incorporation of the recorded flowering data in the calculation of expected pollination rates improved the goodness of fit with observed values by only 0.77%. Suggestions to reduce the variance in paternal contributions were presented. However, contamination was considered more threatening to the genetic integrity of perennial ryegrass germplasm than variation in pollination rates between plants, and indicated the need for improved measures to avoid gene flow from other germplasm.  相似文献   

The distribution and spreading pattern of Dermacentor reticulatus over its threshold area in the Czech Republic--how much is range of this vector expanding?     

Siroký P  Kubelová M  Bednář M  Modrý D  Hubálek Z  Tkadlec E 《Veterinary parasitology》2011,183(1-2):130-135

Host-seeking Dermacentor reticulatus ticks were detected by flagging method at 46 localities at south-east part of the Czech Republic, in the basins of rivers Morava and Dyje. Exact north-west distribution limits of D. reticulatus were defined in this area for the first time. Detailed prediction map of probabilities of D. reticulatus occurrence was obtained using GIS analysis. Spatial model delimited a south-north gradient in probability across the studied area, with highest probabilities above 0.8 in its southernmost part. Abundance of D. reticulatus varied markedly between localities in interval 0.33-222 of ticks per flag per hour. The highest abundances were in flooded areas at lower streams, towards upper streams abundance and density of these ticks decreased. Females prevailed in samples with population sex ratio of 0.413, significantly deviating from parity. Larvae and nymphs of this species were not detected by flagging. Although D. reticulatus range expansion probably did not reach such a degree as reported in other countries, these ticks became very abundant in some parts of studied area. Since spreading of vector-borne diseases became a problem in Europe, the knowledge of their exact recent geographic ranges is important for future modelling of their shift predictability.  相似文献   

Condensed tannins act against cattle nematodes     

Novobilský A  Mueller-Harvey I  Thamsborg SM 《Veterinary parasitology》2011,182(2-4):213-220

The use of natural plant anthelmintics was suggested as a possible alternative control of gastrointestinal nematodes (GIN) in ruminants. Direct anthelmintic effects of tannin-containing plants have already been shown in sheep and goat GIN. These anthelmintic properties are mainly associated with condensed tannins. In the present study, we evaluated possible in vitro effects of three tannin-containing plants against bovine GIN. Effects of Onobrychis viciifolia, Lotus pedunculatus and Lotus corniculatus condensed tannin (CT) extracts on Cooperia oncophora and Ostertagia ostertagi were determined by a larval feeding inhibition assay (LFIA) and a larval exsheathment assay (LEA). In the LFIA, all three plant extracts significantly inhibited larval feeding behaviour of both C. oncophora and O. ostertagi first stage larvae in a dose-dependent manner. The L. pedunculatus extract, based on EC(50) (effective concentration for 50% inhibition), was the most effective against both nematodes, followed by O. viciifolia and L. corniculatus. The effect of CT extracts upon larval feeding behaviour correlates with CT content and procyanidin/prodelphidin ratio. Larval exsheathment of C. oncophora and O. ostertagi L3 larvae (third stage larvae) was also affected by CT extracts from all three plants. In both in vitro assays, extracts with added polyvinylpolypyrrolidone, an inhibitor of tannins, generated almost the same values as the negative control; this confirms the role of CT in the anthelmintic effect of these plant extracts. Our results, therefore, indicated that tannin-containing plants could act against cattle nematodes.  相似文献   

West-to-east differences of Babesia canis canis prevalence in Dermacentor reticulatus ticks in Slovakia     

Kubelová M  Tkadlec E  Bednář M  Roubalová E  Siroký P 《Veterinary parasitology》2011,180(3-4):191-196

Babesia canis canis is the most frequent causative agent of canine babesiosis in Central Europe, frequently causing severe disease. Recently, many new endemic foci of this disease have been reported from European countries. Growing incidence of canine babesiosis was recorded also in Slovakia during the last decade, from first cases in eastern Slovakia ten years ago to recent cases all over the south of the country. We have used nested PCR-RFLP method to study prevalence of B. c. canis in its natural tick vector Dermacentor reticulatus, collected at three geographically isolated lowland areas of southern Slovakia situated in the southeast, southwest, and west of Slovakia, respectively. The highest prevalence of B. c. canis was observed in D. reticulatus from eastern Slovakia (14.7%; n=327), whereas the prevalence in southwest was significantly lower (2.3%; n=1205). Notably, all 874 D. reticulatus ticks collected at Záhorská ní?ina lowland (W Slovakia) were B. c. canis-negative. Recorded differences in Babesia prevalence concurs well with the shift in incidence of clinical cases of canine babesiosis as observed by vet practitioners. Presented results revealed that eastern Slovakia represents an area of high risk of B. c. canis infection, whereas western areas of the country still remain Babesia canis-free.  相似文献   

Molecular evidence of genetic diversity changes in pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.) germplasm after long-term maintenance     

Jaroslava Cieslarová  Petr Smýkal  Zuzana Dočkalová  Pavel Hanáček  Stanislav Procházka  Miroslav Hýbl  Miroslav Griga 《Genetic Resources and Crop Evolution》2011,58(3):439-451

Maintaining germplasm genetic integrity is a key objective of long-term ex situ conservation. Periodic regeneration, performed on limited plots with small number of individuals, increases the risk of genetic drift and genetic diversity changes. In this study, six accessions of white flowered, dry seed pea varieties (Pisum sativum L. subsp. sativum var. sativum): Bohatyr, Klatovsky zeleny, Hanák, Moravsky hrotovicky krajovy, Raman and Viktoria-75 and four accessions of colour flowered, fodder pea (P. sativum subsp. sativum var. arvense (L.) Poiret: Arvika, Česky banán, Moravská krajová and Niké, representing Czechoslovak varieties and landraces, bred over the last 40–80 years, were analyzed using ten microsatellite locus specific markers. Each accession was represented by 20 individual seeds of two temporally different samples, spanning the period of 20 or 40 years. Together with intra-accession variation (except of cv. Hanák), evidence of genetic changes, e.g. differences in allele frequencies as well as genetic composition of sample, was detected in six out of ten accessions (Arvika, Bohatyr, Česky banán, Moravsky hrotovicky krajovy, Moravská krajová and Raman). Evidence of genetic erosion was found in three accessions (Česky banán, Moravsky hrotovicky krajovy and Raman), while in another three (Arvika, Bohatyr and Moravská krajová) the level of diversity was found to have increased. Moreover in three samples of Bohatyr (2004) and Klatovsky zeleny (1963 and 2004), low levels of heterozygosity was detected. These results demonstrate that in pea, a self-pollinating and highly homozygous plant, the danger of the loss of genetic integrity exists. These findings are significant for long-term ex situ germplasm management.  相似文献   

First report of a 16SrIII-B subgroup phytoplasma associated with leaf reddening, virescence and phyllody of purple coneflower     

Jana Fránová  Josef Špak  Marie Šimková 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(1):7-12

Purple coneflower plants showing leaf reddening and flower abnormalities were observed in South Bohemia (Czech Republic). Transmission electron microscopy observations showed phytoplasmas in sieve cells of symptomatic plants but not in healthy ones. Polymerase chain reactions with universal and group specific phytoplasma primers followed by restriction fragment length polymorphism analyses of 16S rDNA allowed us to classify the detected phytoplasmas into the X-disease group, ribosomal subgroup 16SrIII-B. Sequence analyses of the 16S-23S ribosomal operon (1684 bp), ribosomal protein L15, and protein translocase genes (1566 bp) confirmed the closest relationship with phytoplasmas belonging to the 16SrIII ribosomal group, specifically the 16SrIII-B subgroup. The current study reports purple coneflower as a new host for the X-disease phytoplasma group in the Czech Republic and worldwide.  相似文献   

Biotic homogenization of Central European urban floras depends on residence time of alien species and habitat types     

Zdeňka Lososová  Milan Chytrý  Lubomír Tichý  Jiří Danihelka  Karel Fajmon  Ondřej Hájek  Kateřina Kintrová  Deana Láníková  Zdenka Otýpková  Vladimír Řehořek 《Biological conservation》2012,145(1):179-184

Spread of alien species may result in biotic homogenization, i.e. increasing similarity between biotas of different areas. We examined whether the flora of Central European cities is becoming homogenized because of the spread of alien species, whether the contribution of aliens to homogenization depends on residence time, and whether habitats under more intense human pressure are more homogenized. Using floristic composition data from a standardized sample of 1-ha plots located in seven habitat types in 32 cities in Central Europe, Belgium and the Netherlands, we compared homogenization effects of archaeophytes (pre-AD 1500 aliens) and neophytes (post-AD 1500 aliens) using rarefaction curves, Jaccard dissimilarity index, Mantel tests and homogenization index. We found that archaeophytes contributed to homogenization and neophytes to differentiation of floras among cities, but generally the spread of alien species caused differentiation. Differentiation was low in the most disturbed urban habitats, such as city squares, boulevards or early successional sites, but was strongest in moderately disturbed habitats, such as city parks and residential areas with an open building pattern. We conclude that biotic homogenization depends on alien plants’ residence time. Aliens introduced within the past five centuries are often rare, not yet having achieved their potential range; they therefore increase floristic differentiation. Conversely, species introduced more than five centuries ago have had sufficient time to disperse into most suitable habitats, and consequently contribute to homogenization. Although invasions may therefore initially increase biodiversity, they could ultimately lead to homogenization. These processes are faster and stronger in more disturbed habitats.  相似文献   

Nutritional supplement use among Slovenian adolescents     

Šterlinko Grm H  Stubelj Ars M  Besednjak-Kocijančič L  Golja P 《Public health nutrition》2012,15(4):587-593

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