马铃薯不同级别脱毒种薯病毒再侵染情况及产量变化

通过对大西洋原原种、一级原种、二级原种、一级种薯和二级种薯的生产试验及其PVX、PVY、PVS、PLRV病毒的DAS-ELISA检测,结果表明,从原原种到一级种薯的生产过程中,产量随着脱毒种薯代数的增加而升高,其中以二级原种生产一级种薯的增产幅度最显著;除原原种不带以上4种病毒外,一级原种、二级原种分别带3%、13.3%的PVS病毒,一级种薯带PLRV和PVS病毒,带毒率分别是5.8%、21%,二级种薯带PVY、PVS、PLRV病毒,带毒率分别是8.9%、30%、13%.     

Participatory varietal selection in rice in Nepal in favourable agricultural environments – A comparison of two methods assessed by varietal adoption

Two participatory approaches to varietal selection were compared in February-sown (Chaite) rice and main-season rice in high potential production systems in Nepal. One method, called farmer managed participatory research (FAMPAR), was researcher intensive, while the other, called informal research and development (IRD), demanded fewer resources. The trials were conducted in 18 villages in high potential production systems in Chitwan and Nawalparasi districts of Nepal. Six new varieties of Chaite rice and 16 of main-season rice were tested in over 300 trials of Chaite rice and nearly 1100 trials of main-season rice over two years in 1997 and 1998. Surveys were done in 1997, 1998 and 1999 to record the extent of adoption and spread of the new rice varieties in the study villages. In many cases, farmers tested varieties for two years before deciding whether to adopt or drop them. Varieties were quite widely accepted, adopted for niches in a few villages, or rejected. The two participatory approaches identified the same varieties, but FAMPAR, which used formal survey methods, was more useful for diagnosing reasons for adoption or rejection. However, IRD used much cheaper anecdotal methods of evaluation, so it was more cost-effective. Moreover,farmer-to-farmer seed dissemination was higher in IRD villages, probably because farmers in FAMPAR villages felt that the project would re-supply seed if needed. The benefits from both approaches are considerable, but to adopt them substantial policy changes in varietal testing, release and extension systems will be required. This revised version was published online in August 2006 with corrections to the Cover Date.     

Development of SCAR markers linked to the Ns locus in potato

A random amplified polymorphic DNA marker OPG17₄₅₀ linked to the Ns gene that confers resistance of potato to potato virus S (PVS), was used to develop sequence‐characterized amplified region (SCAR) markers. After cloning and sequencing of OPG17₄₅₀ new polymerase chain reaction (PCR) primers were designed to generate dominant (SCG17₃₂₁) and codominant (SCG17₄₄₈) markers. For SCG17₄₄₈, polymorphism between susceptible and resistant genotypes was recovered after digestion of the marker with the restriction enzyme Muni. In addition to the band corresponding to ‘susceptible’ allele that does not contain the Muni cleavage site, two bands of approximately 251 bp and 197 bp were observed in the resistant genotypes. The usefulness of these SCAR markers was verified in diploid potatoes possessing the Ns locus from clone G‐LKS 678147/60, and in tetraploid potatoes derived from G‐LKS 678147/60 and from clone MPI 65118/3.     

Cryopreservation of carnation (Dianthus caryophyllus L.) shoot tips by encapsulation-vitrification

Shoot tips excised from in vitro cultured plants of Dianthus caryophyllus L. (cv. Pallas, cv. Pink Candy and cv. Wanessa) were successfully cryopreserved using an encapsulation-vitrification method. Shoot tips (2–3 mm in length) were encapsulated in sodium alginate, precultured on liquid Murashige and Skoog (1962) medium supplemented with various sucrose concentrations (0.25, 0.5, 0.75, 1.0 M) for 24 h or 48 h and dehydrated with the vitrification solution PVS2 (up to 4 h) at 24 °C or 0 °C prior to direct immersion in liquid nitrogen (−196 °C). A maximum of shoot regeneration from cryopreserved shoot tips was obtained with the following combinations: preculture in 0.5 M sucrose and 180 min dehydration treatment at 0 °C for cv. Pallas (60% shoot formation), or preculture in 0.75 M and 200 min dehydration at the same temperature for cv. Pink Candy (66.6% shoot formation) and cv. Wanessa (73% shoot formation).     

3种检测方法在脱毒马铃薯种薯病毒检测中的应用及检测效果比较

为进一步明确适用于脱毒马铃薯种薯的病毒检测方法,为脱毒马铃薯生产提供更为有效和准确的病毒检测技术指导。应用反转录聚合酶联式反应(RT-PCR)、双抗体夹心-酶联免疫吸附法(DAS-ELISA)以及胶体金免疫层析技术(GICA)3种方法,对脱毒马铃薯生产中的马铃薯X病毒(PVX)、S病毒(PVS)进行检测,在不同品种及不同繁育等级的种薯中分别比较3种方法的检测效果。结果表明,RT-PCR对马铃薯原原种中的2种病毒检测效果显著优于其他2种方法;3种方法对一级种的2种病毒检测效果无显著差异。RTPCR非常适用于原原种病毒的检测;ELISA方法对原种及一级种大样本抽检更为适用,而GICA因成本高,更适宜一级种小样本的快速抽检。     

The effect of feeding time on potato virus S transmission byMyzus persicae (Sulz.) andAphis nasturtii Kalt, aphids

Summary The relationship between the feeding time and potato virus S (PVS) transmission byMyzus persicae andAphis nasturtii was studied. The optimal acquisition feeding time forM. persicae was at 30 sec to 2 min (2.9% infected plants). For transmission byA. nasturtii the highest level of infection was after acquisition feeding at 15 sec (11%), 30 sec and 2 min (9.6% each) and there was a significant linear decrease of plant infection as feeding time extended from 7 sec to 64 min. A different relationship has been obtained for inoculation feeding. In PVS transmission byM. persicae the plant infection increased from 0% at 7 sec feeding to 2.9% at 8 and 32 min. In virus transmission byA. nasturtii the infection was 4% after 7 sec feeding and increased significantly to 12.2% at 64 min feeding time.     

Detection of strains of potato virus S by nucleic acid spot hybridization (NASH)

Summary Two complementary DNA (cDNA) clones (0.9 kb and 1.6 kb) reacting to the ordinary strain of potato virus S (PVS) were compared with single-stranded randomly primed cDNA (prepared to total genomic RNA) as probes for various strains of PVS, using the technique of nucleic acid spot hybridization (NASH). The cDNA clones detected 11 PVS isolates well, including both Andean and ordinary strains, while one of each strain was detected weakly. As little as 5 femtograms of PVS RNA could be detected. A low cross hybridization was observed with cDNA probes to PVS with potato virus M and carnation latent virus both members of the carlavirus group. No cross homology was detected with seven other potato viruses. NASH was as sensitive and specific as enzyme-linked immunosorbent assay (ELISA), with no pretreatments of crude sap being required before spotting on nitrocellulose filters. Cloned cDNA probes would be suitable for mass screening of PVS.     

PVS评估与差距分析——现代公共管理理念在兽医体系能力建设中的实践探析

伴随全球化格局下世界政治经济社会自然环境发生的巨变,特别是“同一世界,同一健康”理念影响的深入,兽医工作的复杂程度显著增加。世界动物卫生组织（OIE）开展的兽医体系效能（PVs）评估和差距分析,意在帮助成员提升兽医体系能力,实现保护全球动物卫生、兽医公共卫生、生态环境,保障动物源性食品供给与安全,减少贫困的职责目标。本文通过解析PVS评估和差距分析方法中蕴含的现代公共管理理念、原理和方法,探讨应用时可能出现的干扰因素,提出了我国实行良好兽医管理、完善兽医体系、强健履职能力、保障兽医工作成效全面提升的措施建议。     

马铃薯六种主要病毒通用RT-PCR检测体系的建立

马铃薯X病毒(PVX)、马铃薯Y病毒(PVY)、马铃薯S病毒(PVS)、马铃薯卷叶病毒(PLRV)、马铃薯M病毒(PVM)和马铃薯A病毒(PVA)是马铃薯生产田中发生率较高、危害较严重的病毒,因此,建立特异性强、灵敏度高、检测速度快的RT-PCR分子检测体系对保障马铃薯种薯质量具有非常重要的意义。试验筛选了6种病毒的特异引物、优化了PCR部分的试剂以及确定了退火温度。结果表明,当Mg2+浓度为2.6 mmol/L、d NTPs浓度为0.1 mmol/L、Taq DNA聚合酶浓度为0.03 U/μL,以及退火温度为55.5℃时反应体系最稳定。最终,建立了一套通用RT-PCR检测体系,只需要变换每种病毒的引物,就可以实现对PVX、PVY、PVS、PLRV、PVM和PVA病毒的RT-PCR检测。每种病毒检测灵敏度均能达到pg以上。     

香蕉种质资源超低温保存技术研究进展

香蕉是一种大型草本植物,多数品种没有种子或单性结实,通常以无性繁殖方式为主。由于其生殖特征,难以通过传统杂交育种的方法来进行品种改良,而多是采用体细胞突变的方法来选育新品种。因此,香蕉资源的多样性对香蕉新品种改良尤为重要。但由于常(低)温离体保存、田间活体保存方法易受到生物或非生物胁迫等影响因素限制费力、耗能,其种质资源的长期有效保存对育种工作而言极具挑战性,而超低温保存技术是一种长期有效的保存方法。本研究主要针对香蕉超低温保存的不同方法,总结了影响香蕉超低温保存效果的几个关键因素。