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Fa-chao SUN Min TAN Yuan-chao ZHANG Yu-chao WANG Sheng-liang CAO Guo-fei DING Fang-yuan CONG Li-hong GUO Si-dang LIU Yi-hong XIAO 《农业科学学报》2019,18(7):1436-1442
To investigate the epizootic of swine influenza virus(SIV), 60 nasal swabs were collected from a clinical cases of pig farm in Tai'an City, Shandong Province of China in April 2017. SIV was isolated by inoculating into 10-day-old Special Pathogen Free embryonated eggs and the whole genome was sequenced. An H1N1 subtype SIV was isolated and designated as A/swine/Shandong/TA04/2017(H1N1). Phylogenetic analysis showed that apart from the polymerase A(PA) fragment belonging to the 2009 pandemic H1N1 branch, seven genome segments belonged to avian-like H1N1 influenza virus lineage. The cleavage site sequence of the hemagglutinin(HA) protein was PSIQSR↓G, which is a typical molecular biological characteristic. Five potential N-glycosylation sites(N14, N26, N277, N484 and N543) were found in the HA gene. To further investigate the epidemiology of SIV in this farm, the 995 serum samples were assessed with EAH1N1 2009 pandemic H1N1 and H3 N2 antigens. The results showed that the total positive rate was 65.43%. The positive rates of single virus infection detected by EAH1N1, 2009 pdmH1N1 and H3 N2 for serum HI(Hemagglutination inhibition) were 48.35, 30.85 and 7.47%, respectively. The results showed that SIV in Shandong Province has been reassorted in some segments and the SIV-positive rate was high on the SIV outbreak farm. These data provide evidence of an epizootic of SIV. 相似文献
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为提高天麻栽培产量,扩大天麻栽培地域,提高山区有限土地利用率,笔者将影响天麻田间高产栽培的几个关键因子进行比较试验,总结出天麻田间高产栽培的有效措施,为大力发展天麻生产提供了科学依据。 相似文献
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C. Avgoulas L. Bouza A. Koutrou S. Papadopoulou S. Kosmas E. Makridou P. Papastylianou D. Bilalis 《Journal of Agronomy and Crop Science》2005,191(1):1-9
Studies were conducted in four regions of central Greece (Larisa, Karditsa, Livadia, Thiva), to evaluate the productivity and fibre properties (fibre strength and fibre length) of the five most commonly grown cotton cultivars in these regions. The experiments lasted for 6 years (1995–2000). All the characteristics tested were strongly influenced by the factors ‘year’, ‘cultivar’ and ‘region’. Significant cultivar × region, year × cultivar, region × year and cultivar × region × year interactions occurred for all the characteristics studied. The cultivar Alegria had the highest seed‐cotton and lint yield, while Aria had the lowest ones. Both cultivars gave the highest mean lint percentage but the lowest mean boll weight (MBW). Alegria had the lowest fibre strength, while Aria had the highest. The Acala‐type cultivars, Acala SJ2 and Zeta 2, had intermediate seed‐cotton and lint yield, while Vered 171 had high seed‐cotton and satisfactory lint yield. The three cultivars mentioned above had the highest MBW and very good fibre strength. Positive correlation was observed between fibre strength and length. In spite of the fact that mean fibre length was statistically the same in all cultivars, it was influenced by the factor ‘year’, as a result of different weather conditions. The year 1996 was the most unfavourable one for seed‐cotton yield and MBW, because it was characterized by lower than average air temperatures and rather dry conditions for all study sites. The factor ‘region’, a combination of different climatic conditions and cultural practices, influenced significantly all the parameters studied. 相似文献
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A general bio-economic model for beef cattle production was used to define breeding objectives for Charolais cattle to be utilized in a variety of linked production systems. Economic weights were calculated for 16 traits (some with both direct and maternal components) in three production systems (pure-breeding and terminal crossing with beef or dairy cows) and two marketing strategies (sale or fattening of weaned surplus calves). Economic weights for the total breeding objective were calculated as weighted averages, where weights were numbers of cows expected to be mated with Charolais bulls in each production system and marketing strategy. Results suggest that the direct component of calving performance and cow longevity were of primary economic importance in all systems. Conception rate of cows and weaning weight reached about 50% of the standardized economic weight of calving performance in purebred systems with sale of weaned calves, whereas in purebred systems with fattening the economic importance of the direct component of cow conception rate, losses at calving, mature weight of cows, weaning weight, and fattening traits were of equal importance (each approximately about 20% that of calving performance). In terminal crossing systems, weaning weight was important when calves were sold at weaning, and fattening traits were important for systems selling fattened animals. The bio-economic model performed well under the conditions of this demonstration and could easily be customized for other applications. 相似文献
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Summary Orobanche species are commonly identified using morphological characteristics. In many cases, the distinction of closely related species is difficult, and a molecular tool is more suitable to differentiate them. In this study, genomic polymorphism between morphologically distinct species was investigated through amplification by polymerase chain reaction (PCR) of intersimple sequence repeat (ISSR) regions. Five primers were used to study genetic variation in the morphologically distinct species O. hederae and O. amethystea, as well as the closely related species O. cernua and O. cumana. For the first two species, all the primers detected genetic polymorphism. Anchored primers allowed the identification of more specific molecular markers than non‐anchored tri‐ and tetranucleotide primers. Genetic polymorphism was investigated among three O. hederae populations using the two types of primer. One non‐anchored and two anchored primers detected intraspecific variation, which was not correlated with the geographical location of those populations. The primer (GATA)4 detected polymorphism between five specimens each of O. cernua and O. cumana species collected from different countries, permitting these two closely related species to be clearly differentiated. This study demonstrated that ISSR markers can be highly reliable for precise identification of Orobanche species. 相似文献