Evidence of long distance airborne transmission of Aujeszky's disease (pseudorabies) virus   总被引：4，自引：0，他引：4  

L S Christensen  J Mousing  S Mortensen  K J Soerensen  S B Strandbygaard  C A Henriksen  J B Andersen 《The Veterinary record》1990,127(19):471-474

Aujeszky's disease has been the subject of an eradication campaign in Denmark since 1980. A detailed knowledge of the virus strains present in the country was provided by restriction fragment analyses of older clinical isolates, and of isolates from all the virologically confirmed outbreaks since 1985. The introduction of foreign strains into southern border areas was demonstrated during the winters of 1984/85, 1986/87 and 1987/88. An epizootic during the winter of 1987/88 was shown to correlate with an unusual predominance of southerly winds. Both conventional and specific pathogen free herds became infected. A herd level case-control analysis of the outbreaks during the winter of 1987/88 revealed that there was a positive correlation between the risk of infection and the size of the herd. The observations support the hypothesis of airborne transmission of the disease.  相似文献   

Resistance to the cabbage root fly, Delia radicum, within Brassica fruticulosa     

E.B. Jensen  G. Felkl  K. Kristiansen  S.B. Andersen 《Euphytica》2002,124(3):379-386

Two transgenic Bt rice lines, KMD1 and KMD2, both containing a synthetic cry1Ab gene from Bt, were crossed with conventional rice varieties. The inheritance of resistance to SSB of KMD1 and KMD2was investigated through LSB and field examination of their progenies, e.g. F₁, BC₁ and F₂ populations. In LSBs, 100.0% of newly hatched SSB larvae died on the second day after feeding on leaf tissues of F₁ and GUS positive BC₁ plants, of which the area of leaf tissues consumed by SSB is also similar to that of transgenic parents. These results imply that the resistance of Bt rice to SSB is dominantly controlled and could be easily exploited in hybrid rice production. Field evaluation showed that segregation ratios for SSB resistance to susceptibility in BC₁ populations fit the ratio of 1:1, which was also confirmed by LSBs. However, in F₂ populations, the ratio was significantly smaller than 3:1 for resistant to susceptible plants in all 6 indica × japonica (KMD1 and KMD2) crosses, though it fitted 3:1 in all 4 japonica × japonica crosses. The results implied that the resistance of Bt rice to SSB was controlled by a dominant gene which was present in a homozygous condition in both KMD1 and KMD2, but the inheritance could be affected by other factors. Assays for Cry1Ab protein showed that, in most crosses, the content of Cry1Ab is significantly higher in leaves of GUS positive F₁, BC₁ and F₂ plants than that in transgenic Bt parent plants, which accounts for the high resistance observed in these plants to SSB. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Components of Response in Barley Anther Culture   总被引：2，自引：0，他引：2  

S. Knudsen    I. K. Due  S. B. Andersen 《Plant Breeding》1989,103(3):241-246

Anther culture response with 17 widely-grown varieties and one model variety of barley was studied with one replication from field-grown donor plants and one replication from a growth-chamber. Plants were regenerated from all 18 varieties and green plants were obtained from 16 of them. On average, 1.6 green plants were obtained per 100 cultured anthers from all the material. Estimated variance components for the formation of embryos/callus from the anthers were dominated by the effects of the genotypes and interactions between plant material and environments which together accounted for 60.1 and 17.0 % of the total variation respectively, while environments were nonsignificant for this character. Plant regeneration from embryos/callus were not significantly influenced by either genotype or environments. Components of variance for green plant formation were dominated by the effects of the genotypes, accounting for 73.2 % of the total variation, and a smaller effect from environments accounting for 11.2% of the total variation. Main effects from genotypes on the percentage of green regenerants divided 7 varieties into two distinct groups, indicating that major genetic factors were involved. The genetic basis for green plant regeneration seems different from that governing embryo formation. The results are discussed with respect to the possible prediction of anther culture response for new barley hybrids, as a means for directing the use of barley anther culture towards material that responds well.  相似文献   

Genic microsatellite markers for discrimination of spinach cultivars     

J. Z. K. Khattak    J. L. Christiansen    A. M. Torp    S. B. Andersen 《Plant Breeding》2007,126(4):454-456

A set of simple sequence repeat (SSR or microsatellite) markers was used to discriminate a collection of 33 Spinacia oleracea hybrid cultivars from seven different breeding stations all over the world. All SSR markers were genic microsatellite markers located in coding or non-coding regions of genes of known function. Cluster analysis based on 13 of the SSR markers showed that the spinach hybrids grouped into three clusters. The first two clusters consisted of European spinach types, which were well discriminated according to their origin from different breeding stations. The third cluster was a mixture of Asian as well as European types of spinach. Subclusters in this group did not reflect differences in morphology, earliness or company origin. The data show that genic microsatellites are a powerful tool for discrimination of spinach cultivars.  相似文献   

Electrophoretic Characterization of Quinoa Seed Proteins     

D. J. Fairbanks    K. W. Burgener    L. R. Robison    W. R. Andersen  E. Ballon 《Plant Breeding》1990,104(3):190-195

Quinoa (Chenopodium quinoa Willd) is an important domesticated food crop of the Andean highlands with potential as an alternative crop elsewhere. Among its most attractive characteristics are the quantity and favorable amino acid balance of the seed proteins. The objective of this study was to characterize quinoa seed proteins by electrophoretic mobility, solubility fractionation, and genetic variability from a wide genetic base. Electrophoretic profiles of denatured albumin, globulin, prolamin, and glutelin solubility fractions demonstrated that quinoa seed polypeptides could be classified as either albumin or globulin with most predominant polypeptides in the globulin fraction. Insignificant amounts of protein were present in the prolamin fraction and all polypeptides in the glutelin fraction had identical electrophoretic mobilities to albumins and globulins. Three globulin polypeptides of 34.3, 35.6, and 36.2 kilodaltons in size were highly variable within and among the accessions examined and appear to be coded by at least two loci. Two-dimensional peptide mapping revealed that these three polypeptides were homologous. These highly variable markers could be used for identification and classification of germplasm and elucidation of systematics and genetic variability within the quinoa germplasm pool. All other major polypeptides were electrophoretically invariant among the accessions examined.  相似文献   

Triploid and Hexaploid Regenerants from Hexaploid Timothy (Phleum pratense L.) via Anther Culture   总被引：3，自引：0，他引：3  

A. A. Abdullah    S. Pedersen  S. B. Andersen 《Plant Breeding》1994,112(4):342-345

Pollen embryos were obtained from eight genotypes and viable green plants were regenerated from four genotypes in an anther-culture experiment with 165 genotypes of Phleum pratense L. Formation of proembryos inside the cultured anthers during the first 10—12 days was significantly influenced by genotypes and by the type of nutrient media. Primary embryos developed into multiple secondary embryos before regeneration of plants. Among a total of 62 plants regenerated, only 13 were albinos. Of the green regenerants, 11 were triploid while 35 were hexaploid when DNA-content was measured by flow cytometry. Eight plants with a triploid DNA-content did possess the triploid chromosome number of 21. Triploid and hexaploid regenerants from two different parents showed simplified isozyme (GPI and PGD) banding patterns relative to that of their parents.  相似文献   

Enhancement of RAPD Analysis by Restriction-endonuclease Digestion of Template DNA in Wheat   总被引：1，自引：0，他引：1  

C.R. Riede    D.J. Fairbanks    W.R. Andersen    R.L. Kehrer    L.R. Robison 《Plant Breeding》1994,113(3):254-257

Random amplified polymorphic DNA (RAPD) analysis has proven to be an effective procedure for molecular marker applications in plant breeding, although non-specific amplification may limit its utility in some species. The objective of this study was to determine the effectiveness of restriction-endonuclease digestion of template DNA for elimination of non-specific amplification and generation of heritable RAPD markers. Restriction endonucleases digested wheat DNA to completion in amplification buffer, suggesting that the restriction endonuclease can be added directly to the reaction mixture prior to amplification. A 1-h 37°C step was programmed into the thermal cycler for restriction-endonuclease digestion which was followed immediately by amplification. Non-specific amplification was reduced and DNA marker patterns were altered in digested samples when compared to undigested samples. Genetic segregation of two polymorphic markers tested in F₅ inbred progeny fit expected 1:1 ratios. These results suggest that heritable DNA markers may be generated with reduction in non-specific amplification when restriction-endonuclease digestion of template DNA is conducted as part of the RAPD procedure.  相似文献   

The effect of lupins as compared with peas and oats on the yield of the subsequent winter barley crop     

Christian R. Jensen  Bjarne Joernsgaard  Mathias N. Andersen  Jrgen L. Christiansen  Vagn O. Mogensen  Poul Friis  Carsten T. Petersen 《European Journal of Agronomy》2004,20(4):405-418

New high yielding early maturing cultivars of lupins have been introduced in north-west Europe as grain protein crops in crop rotations. This paper reports on a comparative study of lupins with peas and oats, and of their effect on yield of subsequent winter barley crops. These crops were given five levels of N under irrigated and non-irrigated conditions on sand and loam. Under rain fed conditions the grain yield of pea, oat and lupin varied between 24–36, 34–53 and 18–37 hkg DM ha⁻¹, respectively. Supplemental irrigation raised grain yield of oat to 50–60 hkg DM ha⁻¹, while grain yield in pea was not affected and grain yield in lupin in most cases decreased due to gray mould attack and excessive vegetative growth in the indeterminate lupin variety. Under rain fed conditions, the grain nitrogen content of pea, oat and lupin varied between 137–172, 61–80 and 189–226 kg N ha⁻¹, respectively, and was significantly higher in lupin as compared with pea. On sandy soil, similar low-root densities were found for pea, oat and lupin below 30 cm depth. On sand, at final harvest the residual soil-N of lupin and pea, as measured in a subsequent winter barley crop not supplied with N fertilizer, was 15 and 8–10 kg N ha⁻¹ higher than in winter barley following oat, respectively. The nature of the probably more N-root residues of lupin is discussed. On loam, the residual N of lupin and pea was similar, 18–27 kg N ha⁻¹. On sand, under rain fed conditions preceding lupin and pea as compared with oat, increased the barley grain yield at zero N-application 77 and 49%, respectively; the effect of lupin was significantly higher than that of pea until the highest N-level 120 kg N-application ha⁻¹. On loam under rain fed conditions preceding lupin and pea increased the barley grain yield at zero N-application by 36 and 62%, respectively, as compared with oat; at N-application>60 kg N ha⁻¹ the grain yield was similar after all three crops. For both soil types the same level of effect was found under irrigated conditions. Conclusions: Supplemental irrigation might result in lower grain yield in lupin due to gray mould attack and excessive growth if indeterminate lupin varieties are used. Grain nitrogen yield of lupin is significantly higher than that of pea. On sand, the effect of lupin on the subsequent winter barley grain yield is significantly higher than that of pea, probably due to greater N-root nitrogen residues. On loam, lupin and pea have similar effects on the subsequent winter barley crop.  相似文献   

Development and application of functional markers in maize   总被引：8，自引：0，他引：8  

Thomas Lübberstedt  Imad Zein  Jeppe Reitan Andersen  Gerhard Wenzel  Birte Krützfeldt  Joachim Eder  Milena Ouzunova  Shi Chun 《Euphytica》2005,146(1-2):101-108

Summary Functional markers (FMs) are derived from polymorphic sites within genes causally involved in phenotypic trait variation (Andersen, J.R. & T. Lübberstedt, 2003. Trends Plant Sci 8: 554–560). FM development requires allele sequences of functionally characterized genes from which polymorphic, functional motifs affecting plant phenotype can be identified. In maize and other species with low levels of linkage disequilibrium, association studies have the potential to identify sequence motifs, such as a few nucleotides or insertions/deletions, affecting trait expression. In one of the pioneering studies, nine sequence motifs in the dwarf8 gene of maize were shown to be associated with variation for flowering time (Thornsberry, J.M., M.M. Goodman, J. Doebley, S. Kresovich, D. Nielsen & E.S. Buckler, 2001. Nat Genet 28: 286–289). Proof of sequence motif function can be obtained by comparing isogenic genotypes differing in single sequence motifs. At current, the most appropriate approach for this purpose in crops is targeting induced local lesions in genomes (TILLING) (McCallum, C.M., L. Comai, E.A. Greene & S. Henikoff, 2000. Nat Biotechnol 18: 455–457). In central Europe, maize is mainly grown as forage crop, with forage quality as major trait, which can be determined as proportion of digestible neutral detergent fiber (DNDF). Brown midrib gene knock out mutations have been shown to be beneficial for forage quality but disadvantageous for overall agronomic performance. Two brown midrib genes (bm1 and bm3) have been shown to be involved in monolignol biosynthesis. These two and additional lignin biosynthesis genes have been isolated based on sequence homology. Additional candidate genes putatively affecting forage quality have been identified by expression profiling using, e.g., isogenic bm lines. Furthermore, we identified an association between a polymorphism at the COMT locus and DNDF in a collection of European elite inbred lines.  相似文献   

Effect of genotype,environment and carbohydrate on anther culture response in head cabbage (Brassica oleracea L. convar. capitata (L.) Alef.)     

N. Roulund  L. Hansted  S. B. Andersen  B. Farestveit 《Euphytica》1990,49(3):237-242

Summary The effect of genotype, growing conditions for donor plants and type and concentration of carbohydrate in the culture medium was investigated for anther culture of head cabbage (white cabbage, savoy cabbage, pointed-headed cabbage). Strong genotypic effects on embryo formation from the cultured anthers were shown as well as superior embryo formation from anthers of field grown donor plants compared to plants grown in the greenhouse. When comparing 7, 10 and 13% sucrose in the medium, embryo response increased with increasing sucrose concentration. With maltose, which was generally inferior to sucrose as carbohydrate source for anther culture, the embryo response did not increase with maltose concentration above 10 per cent.  相似文献