Gas chromatography for detection of citrus infestation by fruit fly larvae (Diptera: Tephritidae)     

Paul E. Kendra  Amy L. Roda  Wayne S. Montgomery  Elena Q. Schnell  Jerome Niogret  Nancy D. Epsky  Robert R. Heath 《Postharvest Biology and Technology》2011,59(2):143-149

Tephritid fruit flies are serious economic pests worldwide. As larvae, they feed and develop within the pulp of host fruits, making infestation difficult to detect by visual inspection. At U.S. ports of entry, incoming produce shipments are checked for infestation by manually cutting open a small sample of fruit and searching for tephritid larvae. Consequently, there is a need for more sensitive, high-throughput screening methods. This study evaluated gas chromatography (GC) as a potential technology for improved detection of hidden infestation. Grapefruits (Citrus × paradisi Macfad.) infested with immature stages of the Caribbean fruit fly Anastrepha suspensa (Loew) (Diptera: Tephritidae) were examined to determine if infested fruit emitted a chemical profile distinct from that of non-infested fruit. Peaks identified by GC analysis were grouped into three classes. Chemicals detected in similar quantities in all samples, or slightly elevated in infested samples, were regarded as non-diagnostic background volatiles. Chemicals highly elevated after oviposition, during the last instar exit stage, and in experimentally-pierced fruit were interpreted to be indicators of citrus peel injury, and included d-limonene and β-ocimene. Chemicals elevated exclusively in the larval infestation stages were considered indicators of feeding damage and potentially diagnostic of infestation, and included hexyl butanoate and an unidentified compound. The peaks associated with injury and feeding were also detectable with a portable ultra-fast GC analyzer that required less than 80 s per sample. Further studies will investigate the potential application of these results for development of a rapid, non-destructive screening method for detection of tephritid infestation.  相似文献   

Intergeneric hybridization between Hippolytia kaschgarica (Krascheninnikov) Poljakov and Nipponanthemum nipponicum (Franch. ex Maxim.) Kitam.     

Ge Hong  Xiaobo Wu  Yucheng Liu  Fei Xie  Zhaohui Liu  Wenchao Liu  Huien Zhao 《Genetic Resources and Crop Evolution》2015,62(2):255-263

  相似文献   

棉花单核苷酸多态性标记研究进展   总被引：1，自引：0，他引：1  

王振玉  李威  周晓箭  裴小雨  刘艳改  周克海  张文生  孟清芹  王海风 《棉花学报》2016,28(4):399-406

单核苷酸多态性标记已在农作物研究中得到广泛应用并取得重大进展。为了便利棉花SNP(Single nucleotide polymorphism)标记的研究和应用,介绍了利用基因芯片、简化基因组测序、重测序等在棉花中开发SNP标记的方法 ,综述了SNP标记在棉花遗传图谱构建、数量位点的定位和分子标记辅助育种、基因组测序以及系统进化等研究中的应用。并对异源四倍体棉花中SNP标记开发时,同源序列位点和部分同源序列位点上的SNP标记辨别问题进行了系统探讨,对其快捷的开发、检测方式和在数量基因定位中的应用前景进行了展望。  相似文献   

Variation of Color and Ray Pattern in Juvenile Shells in Hatchery‐produced Freshwater Triangle Pearl Mussels,Hyriopsis cumingii,in China     

Haibo Wen  Ruobo Gu  Zheming Cao  Xin Zhou  Zhijuan Nie  Xianping Ge  Pao Xu  Xin Zhou  Zhijuan Nie  Xianping Ge  Pao Xu  Dan Hua 《Journal of the World Aquaculture Society》2013,44(1):154-160

The variation and inheritance of juvenile shell color and pigmentation pattern in the freshwater mussel, Hyriopsis cumingii, were reported in 1‐yr‐old progeny of eight families. There were three distinctive phenotypes of shell color and pigmentation patterns observed, including a greenish‐brown shell with radial rays, yellowish‐brown shell with radial rays, and yellowish‐brown shell without radial rays. There were no greenish‐brown individuals without radial rays. The shell color phenotypes showed variation with the growth in juvenile Stage I (1–3 cm in shell length), and the percentage of individuals with radial rays increased once they reached a shell length of 11 mm and then stabilized after reaching 20 mm in shell length. Shell color differentiation became more apparent at a shell length of 26 mm. Results of chi‐square tests of the segregation ratio of shell color or ray phenotypes obtained from eight families at juvenile Stage II (6–9 cm in shell length) suggested that greenish‐brown is controlled by a dominant allele (G) and yellowish‐brown‐shell phenotype is by a recessive allele (y); the ray pattern phenotype is controlled by a recessive (r) and a dominant allele (R) at a single locus. Shell color phenotypes may be a useful genetic marker for future selective breeding of triangle pearl mussels.  相似文献   

非洲猪瘟自然弱毒株演变进程     

戈胜强  王振忠  吕艳  屈海龙  张潇月  胡永新  钱莺娟  吴晓东  王志亮 《中国动物检疫》2021,38(3):68-73

自2018年非洲猪瘟(African swine fever,ASF)传入中国以来疫情得到了有效控制。但2021年以后,我国的ASF流行情况出现了新的变化,临床中出现了“自然变异株”。这些毒株可能导致感染后临床症状不典型,容易与其他疫病混淆等问题。这与国外的流行演变规律一致,即当ASF在一个国家或地区流行较长时间后,其临床表现将由急性发病转变为缓慢发病或出现新的临床表现。经过多年的观察积累,国外已经对该病毒的流行规律特别是自然弱毒株的演变进程有了大量记载,但国内目前尚无这方面的描述。为此,就ASF自然弱毒株的演变进程进行综述,从而提出加强血清学诊断产品研发、加快产业化报批进程、适时开展血清学监测追溯等建议,以期为我国ASF科学防控提供参考。  相似文献   

包虫病宣传片《格桑花开》宣传效果评估     

刘平  王幼明  康京丽  黄保续  葛威  李翠玲  张玉宝  孙向东 《中国动物检疫》2021,38(7):1-4

《格桑花开》是首次以情景剧形式进行人兽共患病防治宣传而拍摄的科普影片。影片开播后,各省组织农牧民,通过集中播放或自行观看等方式进行防治知识宣传。为评价《格桑花开》的宣传干预效果,播放1年后,在新疆、青海、甘肃、四川4省区抽取农牧民进行包虫病防控知识、态度、行为问卷调查。结果显示:与干预前的基线调查相比,养殖户的包虫病防治相关知识、态度和行为平均得分分别上升了8.4%、16.5%和15.2%,各调查省区干预后的平均得分均有提升。结果表明,在文化水平偏低、少数民族语言使用较多的地区,用情景剧方式对动物疫病进行防治宣传教育效果较好。  相似文献   

全球基因I型非洲猪瘟病毒流行与疫苗研究进展     

戈胜强  屈海龙  路皓东  韩乃君  胡永新  左媛媛  张潇月  吴晓东  王志亮 《中国动物检疫》2021,38(12):70-76

非洲猪瘟病毒已在我国定殖并形成较大污染面,国内样品中发现基因I型非洲猪瘟病毒,提示当前临床中实际流行的病毒种群更加复杂。基因I型毒株从1957年传入葡萄牙后,研究人员就开始对其进行研究。多年来,国外对基因I型毒株的流行分布情况特别是弱毒疫苗进行了大量研究,但国内目前尚无这方面的分析讨论。为此,作者就基因I型非洲猪瘟病毒流行与疫苗研究现状进行综述,以期为我国非洲猪瘟的科学防控提供参考。  相似文献   

Free-range system and supplementation of 25-hydroxicholecalciferol increases the performance and serum vitamin levels in mixed-parity sows     

Josiane C. Panisson  Nathália C. Oliveira  Cristina M. Sá-Fortes  Adsos A. Passos  Claudia C. da Silva  Wagner A. G. Araújo  Idael M. G. Lopes  Gleison M. S. Costa  Iara Q. Ataíde  Bruno A. N. Silva 《Animal Science Journal》2021,92(1):e13592

Improvements in sow productivity have raised questions regarding dietary vitamin D recommendations. The present study aimed to evaluate the effects of the housing system with access to sunlight exposure and supplementation of 25-hydroxicholecalciferol on performance and serum levels of 25(OH)D₃ in sows during gestation and lactation. Sows were distributed in an experimental design with two housing systems: gestation crates or gestation free-range system with external area for sunlight exposure; and two diets: 0 or 50 μg of 25-hydroxicholecalciferol kg⁻¹. The use of 25-hydroxicholecalciferol tended (P = 0.052) to improve total born and influenced (P = 0.046) on number of born alive. Litter weight at birth was also increased (P = 0.01) by 25-hydroxicholecalciferol supplementation; 25-hydroxicholecalciferol supplementation and housing system (free-range with sunlight exposure) tended to increase weaning weight (P = 0.07) and litter daily gain (P = 0.051) during lactation. Exposure to sunlight and 25-hydroxicholecalciferol supplementation increased 25(OH)D₃ serum levels when compared with control treatment during gestation (136.95 vs. 113.92 ng mL⁻¹; P = 0.035) and lactation (120.29 vs. 88.93 ng mL⁻¹; P = 0.026). In conclusion, the association of 25-hydroxicholecalciferol supplementation with exposure to sunlight during gestation improved significantly 25(OH)D₃ serum levels and consequently performance traits in gestation and lactation.  相似文献   

Object‐Based Mapping of Karst Rocky Desertification using a Support Vector Machine     

E.‐Q. Xu  H.‐Q. Zhang  M.‐X. Li 《Land Degradation \u0026amp; Development》2015,26(2):158-167

Accurate and cost‐effective mapping of karst rocky desertification (KRD) is still a challenge at the regional and national scale. Visual interpretation has been utilised in the majority of studies, while an automated method based on pixel data has been investigated repeatedly. An object‐based method coupling with support vector machine (SVM) was developed and tested using Enhanced Thematic Mapper Plus (ETM+) images from three selected counties (Liujiang, Changshun and Zhenyuan) with different karst landscapes in SW China. The method supports a strategy of defining a mapping unit. It combined ETM+ images and ancillary data including elevation, slope and Normalized Difference Vegetation Index images. A sequence of scale parameters estimation, image segmentation, training data sampling, SVM parameters tuning and object classification was performed to achieve the mapping. A quantitative and semi‐automated approach was used to estimate scale parameters for segmenting an object at an optimal scale. We calculated the sum of area‐weighted standard deviation (WS), rate of change for WS, local variance (LV) and rate of change for LV at each scale level, and the threshold of the aforementioned index that indicated the optimal segment level and merge level. The KRD classification results had overall accuracies of 85·50, 84·00 and 84·86 per cent for Liujiang, Changshun and Zhenyuan, respectively, and kappa coefficients are up to 0·8062, 0·7917 and 0·8083, respectively. This approach mapped six classes of KRD and offered a visually appealing presentation. Moreover, it proposed a conceptual and size‐variable object from the classification standard of KRD. The results demonstrate that the application of our method provides an efficient approach for the mapping of KRD. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

梯形组合刀盘设计及作业性能试验     

史岩鹏  翟长远  朱瑞祥  闫小丽  葛世强  李成鑫  时永 《农机化研究》2015,(12):182-187

针对免耕播种机开沟器工作中容易出现缠草堵塞、草土混杂及干湿土混杂影响播种质量的问题,设计了一种新型梯形组合刀盘,制作了试验装置,并进行了土槽和田间试验。试验表明:梯形组合刀盘在秸秆覆盖量不大于1.2kg/m2时,通过性满足要求;梯形组合刀盘工作时组合刀盘和开沟器先后开出"W"沟和"V"沟,草土分离系数达95%,干湿土分离系数可达91.7%。梯形组合刀盘破茬防堵性能可靠,实现了草土分离及干湿土分离,可为种子萌发及出苗创造良好条件。  相似文献