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排序方式: 共有77条查询结果,搜索用时 31 毫秒
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A. V. Gapeka Yu. G. Volkov N. N. Kakareka T. I. Pleshakova Z. N. Kozlovskaya A. G. Klykov G. A. Murugova P. M. Bogdan I. V. Konovalova 《Russian Agricultural Sciences》2016,42(6):431-434
Data on the extent and dynamics of the viral diseases affecting cereal crops in breeding nurseries have been obtained as a result of the phytovirological monitoring. The deterious pathogens affecting the spring barley and the spring and winter wheat are identified under the conditions of the region. The necessity to produce the cereal varieties resistant to the viral infections and the use them in breeding is shown. 相似文献
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Risk factors for disease associated with influenza virus infections during three epidemics in horses
Morley PS Townsend HG Bogdan JR Haines DM 《Journal of the American Veterinary Medical Association》2000,216(4):545-550
OBJECTIVE: To identify risk factors associated with respiratory tract disease in horses during 3 epidemics caused by influenza virus infections. DESIGN: Cross-sectional and prospective longitudinal observational studies. ANIMALS: 1,163 horses stabled at a Thoroughbred racetrack. PROCEDURES: Investigations were conducted during a 3-year period. An epidemic of respiratory tract disease caused by influenza virus infections was identified in each year. Routine observations and physical examinations were used to classify horses' disease status. Data were analyzed to identify factors associated with development of disease. RESULTS: Results were quite similar among the epidemics. Concentrations of serum antibodies against influenza virus and age were strongly associated with risk of disease; young horses and those with low antibody concentrations had the highest risk of disease. Calculation of population attributable fractions suggested that respiratory tract disease would have been prevented in 25% of affected horses of all horses had high serum antibody concentrations prior to exposure. However, recent history of vaccination was not associated with reduction in disease risk. Exercise ponies had greater risk of disease than racehorses, which was likely attributable to frequent horse-to-horse contact. CONCLUSIONS AND CLINICAL RELEVANCE: Particular attention should be paid to young horses, those with low serum antibody concentrations, and horses that have frequent contact with other horses when designing and implementing control programs for respiratory tract disease caused by influenza virus infections. It appears that control programs should not rely on the efficacy of commercial vaccines to substantially reduce the risk of disease caused by influenza virus infections. 相似文献
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Dr. Bogdan Bochev 《Genetic Resources and Crop Evolution》1981,29(1):361-367
Summary As a result of the hybridization ofAegilops ovata auct. non L. with theTriticum aestivum L. cultivar Bezostaja 1, new biological variants ofT. sphaerococ-cum
Perc. have been obtained. Besides the basic morphological and biological characters, they possess also some new useful features, such as better expressed winter hardiness, resistance to fungal diseases, and higher content of protein. New botanical varieties ofT. spelta L. are a result of hybridization betweenAe. crassa
Boiss. ssp.vavilovii
Zhuk. (2n = 42) and different cultivars ofT. aestivum. Some of them have useful biological and agricultural characters and are considered to be of interest to further utilization in plant breeding. Thus, on the basis of all these results, new suggestions about the origin of the genusTriticum are made. At the same time, the new biological variants of both of these species increase the possibilities of their practical utilization in wheat breeding.
According to the author's request the term variety was used for the hybrid derivatives. Editors 相似文献
Neue botanische Varietäten vonTriticum sphaerococcum Perc. undTriticum spelta L. aus Kreuzungen von Arten der GattungAegilops L. mitTriticum aesti-vum L.
Zusammenfassung Durch Kreuzungen vonAegilops ovata auct. non L. mit der Sorte Bezostaja 1 vonTriticum aestivum L. wurden neue biologische Varianten vonT. sphaero-coccum Perc. erhalten. Neben den morphologischen und biologischen Merkmalen besitzen sie auch einige neue nützliche Eigenschaften, wie bessere Winterfestigkeit, Resistenz gegenüber Pilzkrankheiten, und einen höheren Proteingehalt. Neue botanische Varianten vonT. spelta L. sind Ergebnis von Kreuzungen zwischenAe. crassa Boiss. ssp.vavilovii Zhuk. (2n=42) und verschiedenen Sorten vonT. aestivum. Einige von ihnen weisen nützliche biologische und pflanzenbauliche Eigenschaften auf und können daher für eine künftige Anwendung in der Pflanzenzüchtung interessant sein. Auf der Grundlage dieser Ergebnisse werden neue Vermutungen über den Ursprung der GattungTriticum angestellt. Die neuen biologischen Varianten beider Arten erweitern die Möglichkeiten ihrer praktischen Nutzung in der Weizenzüchtung.
Triticum sphaerococcum Perc. .spelta L.
Aegilops L. . aestivum L. ë Aegilops ovata auct. non. L. 1 (Triticum aestivum L.) . sphaerococcum perc. , . , , . ,. spelta L. . crassa Boiss. ssp.vavilovii Zhuk. (2n=42) . aestivum. . Triticum. .
According to the author's request the term variety was used for the hybrid derivatives. Editors 相似文献
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H G Townsend S J Penner T C Watts A Cook J Bogdan D M Haines S Griffin T Chambers R E Holland P Whitaker-Dowling J S Youngner R W Sebring 《Equine veterinary journal》2001,33(7):637-643
A randomised, controlled, double-blind, influenza virus, aerosol challenge of horses was undertaken to determine the efficacy of a cold-adapted, temperature sensitive, modified-live virus, intranasal, equine influenza vaccine. Ninety 11-month-old influenza-na?ve foals were assigned randomly to 3 groups (20 vaccinates and 10 controls per group) and challenged 5 weeks, 6 and 12 months after a single vaccination. Challenges were performed on Day 0 in a plastic-lined chamber. Between Days 1 and 10, animals were examined daily for evidence of clinical signs of influenza. Nasal swabs for virus isolation were obtained on Day 1 and Days 1 to 8 and blood samples for serology were collected on Days 1, 7 and 14. There was no adverse response to vaccination in any animal. Following challenge at 5 weeks and 6 months, vaccinates had significantly lower clinical scores (P = 0.0001 and 0.005, respectively), experienced smaller increases in rectal temperature (P = 0.0008 and 0.0007, respectively) and shed less virus (P<0.0001 and P = 0.03, respectively) over fewer days (P<0.0001 and P = 0.002, respectively) than did the controls. After the 12 month challenge, rectal temperatures (P = 0.006) as well as the duration (P = 0.03) and concentration of virus shed (P = 0.04) were significantly reduced among vaccinated animals. The results of this study showed that 6 months after a single dose of vaccine the duration and severity of clinical signs were markedly reduced amongst vaccinated animals exposed to a severe live-virus challenge. Appropriate use of this vaccine should lead to a marked reduction in the frequency, severity and duration of outbreaks of equine influenza in North America. 相似文献
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P S Morley H G Townsend J R Bogdan D M Haines 《Journal of the American Veterinary Medical Association》1999,215(1):61-66
OBJECTIVE: To evaluate efficacy of a commercial vaccine for prevention of infectious upper respiratory tract disease (IURD) caused by equine influenza virus. DESIGN: Double-masked, randomized, controlled field trial. ANIMALS: 462 horses stabled at a Thoroughbred racetrack. PROCEDURE: Vaccine or saline solution placebo was administered 4 times in the population at 6-week intervals. The vaccine contained 3 strains of inactivated influenza virus, and inactivated equine herpesvirus type 4. Horses received 1 or 2 doses of vaccine or placebo prior to onset of a natural influenza epidemic, and were examined 5 d/wk to identify and monitor horses with IURD. Serum antibody concentrations were determined, and virus isolation was performed. RESULTS: Vaccination of horses prior to the influenza epidemic did not result in significant decrease in risk of developing respiratory tract disease. Severity of clinical disease was not different between affected vaccinated horses with IURD and controls with IURD, but median duration of clinical disease was 3 days shorter in vaccinated horses. Serum concentrations of antibodies to H3N8 influenza viruses were lower prior to initial vaccination in horses that were sick during the epidemic, and did not increase in these horses in response to vaccination. On arrival at the racetrack, young horses had lower antibody concentrations than older horses, and did not respond to vaccination as well. CONCLUSIONS AND CLINICAL RELEVANCE: Vaccination was of questionable benefit. A greater degree of protection must be obtained for influenza vaccines to be effective in protecting horses from IURD. Objective field evaluations of commercial vaccines are needed to adequately document their efficacy. 相似文献
9.
Bogdan Flis Beata Tatarowska Dorota Milczarek Jarosław Plich 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(5):453-461
The texture of boiled potato tubers is one of the most important quality traits. The variation of tuber texture is usually examined in relationship with dry matter or starch content. The objective of the work was to examine variation and stability of texture and starch content in tubers grown in various environments. Both traits were evaluated for the set of potato breeding lines and 10 table potato cultivars. The lines were developed in the program of parental lines carried out in M?ochów Research Center, Poland. The environments were represented by three locations, which differed in cultivation system as well as climatic and soil conditions. The traits were influenced by the effects of genotype, location and their interactions. The effect of location on texture was not explained by the changes in starch content. The calculated stability parameters indicated that unstable expression of both traits was more pronounced and more frequent in breeding lines than in the cultivars. The short period of selection used in the development of the parental lines is not conducive to select potato genotypes with stable expression of quality traits. The starch content was at most moderately related with various characteristics of tuber texture. 相似文献
10.
Bogdan M. Strimbu John L. Innes Victor F. Strimbu 《European Journal of Forest Research》2010,129(5):961-974
The use of heuristic techniques in forest planning has been promoted by the need to solve complex problems that cannot be
solved using mixed integer programming. We proved that for merchantability standards ensuring the perfect bin-packing theorem
(PBPT), the maximum volume that can be harvested annually equals the sum of the maximum MAI of the stands. The method accommodates
optimality criteria at the stand level, regarded as maximum MAI, and at the forest level, regarded as maximum annual allowable
cut. We scheduled the harvesting by adjusting the first fit decreasing algorithm (FFD) to the PBPT conditions. When PBPT conditions
were not met, we developed a mixed integer programming solution to adjust the merchantability standards of the stands to the
distributional requirements of the PBPT, an adjustment that ensured the optimal performance of the FFD. The adjusted FFD was
compared with linear programming (LP) and simulated annealing (SA) using two harvesting ages (i.e., one based on MAI maximization
and one determined as the minimal age) and the same set of spatial temporal constraints for three areas in north-eastern British
Columbia, Canada. We found that the adjusted FFD performed 100 times faster than SA and for annual allowable cut (AAC) supplied
results that were more homogenous and at least 10% greater than the AAC supplied by SA. Furthermore, the adjusted FFD seemed
to be relatively insensitive to spatial constraints (i.e., adjacency), while SA displayed a 70% reduction in AAC in response
to an increase in adjacency delay from 1 year to 20 years. The results suggest that both adjusted FFD and SA are impacted
by the selection of the harvesting age, but the adjusted FFD could still outperform SA. 相似文献