砜嘧磺隆25%可湿性粉剂在马铃薯中的残留动态

为了制定砜嘧磺隆在马铃薯生产中的安全使用标准,采用田间试验的方法,研究砜嘧磺隆在马铃薯中的残留动态,应用液相色谱法测定砜嘧磺隆在马铃薯中的残留量。试验结果表明:砜嘧磺隆在马铃薯植株和土壤中降解符合一级化学反应动力学方程C=C0e-kt,砜嘧磺隆在土壤中半衰期为(0.02～3.10 d),在植株中的半衰期为(0.93～2.90 d)。该药属易分解农药(T1/2<30 d)。在马铃薯4叶期时喷药1次,按推荐剂量90 g/hm2及1.5倍剂量135 g/hm2施用25%可湿性粉剂砜嘧磺隆。在收获期马铃薯植株和块茎均未检测出,在马铃薯上的砜嘧磺隆安全使用量推荐为90 g/hm2,建议马铃薯上砜嘧磺隆最大残留限量值MRL暂定为0.1 mg/kg。     

Studies on the sensitivity of a latex agglutination test for the serological detection of potato virus S and potato virus X in Wisconsin

American Journal of Potato Research - A latex agglutination test using capillary pipettes as reaction vessels was a sensitive serodiagnostic procedure for detecting potato virus S (PVS) and potato...     

F0lin—Ciocalteus法测定马铃薯中的总多酚

本文建立了紫外分光光度计法准确测定马铃薯中的总多酚。对影响Folin—Ciocaheus法测定马铃薯中总多酚含量的主要因素进行了研究，确定了在1．0mL样品提取液或标液中依次加入5．0mL水、1．0mL显色剂和3．0mL7．5％碳酸钠溶液，摇匀，显色2h后在765nm测定吸光度的最佳检测条件，并对马铃薯样品进行了测定，精密度为7．7％，回收率为100％。108％。本方法适用于常规实验室马铃薯总多酚的测定。     

Use of jet injection to determine potato cultivar susceptibility to potato viruses A and Yc

Summary The use of a high pressure jet injector to inoculate virus rapidly was compared with graft inoculation to determine cultivar susceptibility to potato virus A (PVA) and potato virus Y^c (PVY^c). Tubers were injected with virus infected potato sap, plant reactions recorded, and virus recovered using a bioassay test and enzyme linked immuno-sorbent assay. The injection method compared well with a traditional grafting procedure for PVY^c susceptibility tests but was unsuitable for testing susceptibility to PVA.     

A procedure to correlate color measuring systems using potato chip samples

Measurement of potato chip color is extremely important to the potato processing industry. A procedure is described whereby finished chip samples were utilized for correlation of one spectrophotometric chip color measurement system with another. Calibration, standardization, sample preparation, randomization and prediction equation development procedures are described.     

马铃薯皮中黄酮类物质测定及含量

以马铃薯皮为试验材料,研究了黄酮类化合物提取方法,获得了提取马铃薯皮中黄酮类化合物的最佳条件,测量了马铃薯皮中体现抗氧化性的黄酮类化合物的含量。试验中,对马铃薯皮中黄酮类化合物进行了提取、分离,以1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl,DPPH)的清除率作为马铃薯皮中提取的黄酮类化合物含量及抗氧化活性的评价指标。通过单因素试验,确定提取溶剂、温度、时间、料液比等对提取结果的影响程度。并在单因素试验的基础上设计4因素3水平的正交试验,从而确定马铃薯皮中黄酮类化合物的最佳提取条件。结果表明,马铃薯皮中黄酮类抗氧化物的提取最佳条件为50℃的温度下用80%丙酮溶液按照料液比1:10的比例提取,提取时间为3 h。在此条件下测得DPPH的清除率为84.62%。在最佳提取条件下提取马铃薯皮中黄酮类化合物,并测得每克烘干后的马铃薯皮中含有约10.95 mg的黄酮类物质,与其它类果实果皮中具有相似的抗氧化活性的黄酮类物质的含量相比明显较高。     

A rapid method of analysis for oil,potato solids and moisture in frozen French fries

A method of analysis for oil, potato solids and moisture in frozen French fries is described. This procedure can be completed in 4–5 hr and oil analysis can be finished within 2–3 hr making it useful for industrial quality control laboratories. The rapid procedure correlates closely with the more rigorous procedure of vacuum drying and Soxhlet extraction and compares favorably for accuracy.     

A rapid micro-starch quantitation method for potato callus and its application with potato tubers

The procedure described was developed as a micro-starch method for potato callus tissue (0.1-0.2% starch on a fresh weight basis) and then evaluated with macro-starch samples of potato tubers harvested during three physiological stages of development. This method consisted of the following steps: (a) a mild alkaline-sonic extraction of starch from lyophilized 80% aqueous ethanol-washed samples, (b) starch hydrolysis of the neutralized, filtered extracts by 1 N HC1, and (c) the determination of liberated glucose by the specific glucose oxidase system. Results with this procedure were as sensitive and accurate (SD ± 0.86%) as with other starch-specific methods with more extensive starch isolation and purification steps.     

A simple and rapid method for the detection of potato spindle tuber viroid (PSTVd) by RT-PCR

Summary A test procedure for PSTVd is described based on immobilisation of plant sap on filter paper, by dotting or tissue printing followed by RT-PCR. Tests were carried out using primarily and secondarily infected potato plants, primarily infected in vitro plants, and potato tubers. Print PCR was shown to be suitable for testing large samples of potato plants whereas dot PCR is recommended for in vitro plantlets and tuber tissue. Bulking one infected plant to 4 or 9 healthy plants gave reliable results with secondarily infected potato plants, but sometimes the test failed to detect PSTVd in primarily infected in vitro plants. Dotted and printed paper squares could be stored at 4°C for at least 2 weeks in Triton X-100 solution or under dry conditions. Storing at room temperature can lead to unreliable results.     

Use of IKI leafroll test to reduce net necrosis storage losses of potatoes

An iodine-potassium-iodide (IKI) starch staining procedure was adapted for use on potato plant leaflets to estimate the frequency of potato leafroll virus (PLRV) infection in potato fields prior to harvest. Large increases in the percentage of tubers with net necrosis occurred during storage among tubers from fields with high PLRV infection rates. Such fields were reliably identified prior to harvest by the IKI test, so their tubers could be processed at harvest to avoid net necrosis storage losses. The test could be performed on hundreds of samples per hour by untrained personnel with commonly available equipment. PLRV infection frequency varied widely in Columbia Basin potato fields. Most infected plants expressed no symptoms but could be detected by the IKI test before harvest. High rates of virus dissemination apparently occur late in the growing season in the Columbia Basin     

The recovery of maleic hydrazide from processed potato products

Summary A method used for estimating extractable maleic hydrazide (MH) concentrations in fresh potato material, concentration range 5–17 mg kg⁻¹, was found not to be suitable for processed potato products (10–33% recoveries) although, boiling potato pieces enhanced recovery by 20%. Each step of the determination was examined and a modified procedure developed with particular emphasis on the extraction of MH from the dried potato matrix, and the quality of the HPLC column used. Potato slices and model systems based on filter papers plus additives were used. Recoveries from fried potato slices were 74±6%. Based on the effect of glucose in reducing extractable MH recoveries, it is suggested that the remainder of the MH (20–25%) is converted into a conjugated structure on reaction with dehydrated sugar (Diels-Alder reaction).     

Selection for resistance to potato leafhopper in potatoes: III. Comparison of two selection procedures

A comparison was made of two breeding procedures for recurrently selecting potato,Solanum tuberosum L., for resistance to infestation by potato leafhopper,Empoasca fabae (Harris). On the basis of selection advance per year, the more efficient procedure involved randomly intermating a group of clones, planting seedling tubers in a field test to measure resistance to infestation, and then bulking the seed from the most resistant clones to complete the selection cycle in one year. A population developed by five cycles of selection (five years) for resistance to infestation using this procedure resulted in a decrease of 57% in the level of infestation from the original population.     

网室中马铃薯脱毒微型薯生产技术

在常规的网室马铃薯脱毒微型薯的生产中,脱毒试管苗的移栽成活率在60%左右,甚至更低,对人力、财力是很大浪费。为了解决这个问题,本文从防虫网棚温室的设施、基质的配制、水肥管理、病虫害综合防治措施等方面进行了改进和建立规范化生产,使试管苗移栽成活率达到97%,以期为高效低成本马铃薯脱毒微型薯工厂化生产提供技术参考。     

Amylolytic activity in stored potato tubers. 1. Estimation usingp-nitrophenyloligosaccharides

Summary Methods for the estimation of amylolytic activity are reviewed. A procedure for the routine extraction of amylolytic activity from freeze-dried powder prepared from potato tubers is described. The extraction medium is buffered at pH 7.0 and contains glycerol, dithiothreitol, calcium chloride and the non-ionic detergent, nonidet P-40. α-Amylase activity and exoamylolytic activity were estimated in crude extracts of potato tubers using the substrates, blockedp-nitrophenyl-maltoheptaoside andp-nitrophenyl-maltopentaoside respectively. These substrates are included in kits supplied by Biocon, (UK) Ltd to measure the α- and ?-amylase activity in cereals. The validity of using these kits for the determination of α- and ?-amylase activity in potato tuber tissue is discussed.     

A comprehensive method for the determination of total potato glycoalkaloids

A method has been developed for the quantitative analysis of total glycoalkaloids (TGA) in potato tubers. The method consists of TGA extraction by suitable solvent mixtures followed by hydrolysis of the glycosides and extraction of the aglycones. The aglycones are then quantitated by nonaqueous titration. The advantages of this method over those previously described are the inclusion of glycoalkaloids that are not measured by other methods, and the simplicity, safety, and rapid nature of the procedure. This method has been applied to the TGA analysis of potato tubers subjected to a variety of storage and treatment conditions.     

Design, Construction, and Testing of an Automated NIR In-line Analysis System for Potatoes. Part I: Off-line NIR Feasibility Study for the Characterization of Potato Composition

An off-line near-infrared reflectance (NIR) feasibility study was conducted to explore the critical steps in the NIR determination of the major potato constituents (dry matter, starch, and protein) in relatively large (10 kg) potato samples. The results were important for the design of an automated industrial analysis system for potatoes with in-line NIR. The 10-kg potato samples were pulped with an industrial rotary saw blade rasp. A critical step in the NIR measurements was the occurrence of phase separation in the potato pulp. Phase separation manifests itself directly after pulping the potatoes and significantly affects the NIR spectrum. Therefore, during the NIR measurements, the potato pulp had to be stirred continuously. The NIR spectra (1,100–2,500 nm) were measured by applying an optical fiber NIR probe (EDAPT-1) connected to the NIR spectrophotometer (Technicon Infralyzer IA 500). NIR models for the concentration of dry matter, starch, and coagulating protein in potatoes have been developed. With the partial least squares regression procedure, promising NIR models were calculated. The NIR models were validated using an independent validation set of potato samples. The root mean square error in prediction of the samples in the validation set was 0.5% (w/w) for dry matter, 0.63 (w/w) for starch concentration, and 0.06% (w/w) for the coagulating protein.     

Potato cultivar identification using simple sequence repeats markers (SSR)

Summary Identification of potato cultivars is currently based on phenotypic characters. Crop inspections are needed at different stages and the increasing number of cultivars means the process is becoming more and more complex. Molecular markers are a possible complementary tool to identify potato cultivars and to rapidly check the identity of seeds lots. In this study 286 potato cultivars produced in France were characterized by Polymerase Chain Reaction (PCR) using Simple Sequence Repeats (SSR) markers. Sequential amplifications with 4 to 5 of the chosen SSR markers enabled complete discrimination between all the cultivars. The patterns were registered in a database and the procedure is now used routinely in France.     

Detection of potato leaf roll virus and potato viruses M,S, X and Y by dot immunobinding on plain paper

Summary Potato leafroll virus and potato viruses M, S, X and Y in green leaves were detected by dot immunobinding (DIB) on plain paper and on nitrocellulose membranes. On both materials, DIB could detect the presence of very small amounts of virus, e.g. 30 pg of purified PVX. The sensitivity of the DIB test on plain paper and on nitrocellulose was compared to Double Antibody Sandwich ELISA (DAS-ELISA) by serial dilutions of infected plant sap made in healthy plant sap. Detection of potato viruses by DIB on plain paper and nitrocellulose was found to be equally sensitive whereas DAS-ELISA was 2 to 8 times more sensitive. Possible simplifications of the DIB procedure to suit the requirements of a routine method were examined. The use of the DIB method for routine testing of potato viruses is discussed.     

Current status and future prospects of bacterial ring rot testing

The bacterial ring rot disease of potato (Corynebacterium sepedonicum) can be detected in seed potato lots by serological tests with greater accuracy than by visual field inspections. Indexing tests can make use of highly specific immunofiuorescence probes, enzyme-linked immunosorbent assays, and perhaps other procedures. Sensitivity and specificity of these procedures need to be determined in order to estimate the confidence with which ring rot can be detected in a seed lot. In addition to the laboratory tests, the sampling strategy determines the efficacy and sensitivity of the indexing procedure. Samples might consist of stems, leaf petioles, or tubers in single or composite units. Disease incidence and number of plants sampled also determine the confidence level with which ring rot can be detected in a potato seed lot. Although research has been conducted on many aspects of ring rot testing procedures, further work needs to be done. Nevertheless, it is anticipated that indexing potato seed lots for the presence of ring rot will be a significant factor in control and eradication of the disease.     

Monitoring metalaxyl resistance in populations ofPhytophthora infestans

Summary Samples of potato foliage infected withPhytophthora infestans were collected from the main potato growing areas in Ireland over a three-year period starting in 1981 when metalaxyl-based fungicides were no longer commercially available. Using the floating disc method, 75% of the isolates tested were found to be resistant to metalaxyl in 1981, 21% in 1982 and only 6% in 1983. The reliability of the test method and the sampling procedure to detect low levels of resistance is discussed.