Table Potato Research Articles

Effect of organic and nitrogen fertilization on selected components in potato tubers grown in a simplified crop rotation

Fertilization is one of the factors of agro-technical practice that determines potato yield volume and quality. This research involved the early table potato cultivar Bila grown in the first year of the tenth (2006) and the eleventh rotation cycle (2009) in a long-term, static field experiment (set up in 1979). A three-year simplified crop rotation included potato – winter rye 1 – winter rye 2. The experimental factors covered: I organic fertilization (without FYM and with FYM at the amount of 30 t ha-1), II nitrogen doses 0, 60, 120, 180 kg N ha-1 under potato and 0, 40, 80, 120 kg N ha-1 under rye. The aim of the present research was to evaluate the yielding and content of selected chemical components of the tubers of cv. Bila potato grown in a simplified system depending on different organic and mineral fertilization regimes, implemented for many years. The results show a significantly positive effect of FYM and nitrogen fertilization on the tuber yield volume and on the content of total protein and magnesium, as well as a negative effect on the content of nitrates(V). However, FYM fertilization increased but nitrogen fertilization decreased the content of ascorbic acid. The highest nutritive value of tubers was achieved after the application of 60 kg N ha -1 . However, a dose higher than 120 kg N ha -1 applied with FYM increased the content of nitrates(V) above the toxicity threshold (200 mg NO3 ¯ kg -1 of the fresh product).

Glycoalkaloid and Calystegine Levels in Table Potato Cultivars Subjected to Wounding, Light, and Heat Treatments

Potato tubers naturally contain a number of defense substances, some of which are of major concern for food safety. Among these substances are the glycoalkaloids and calystegines. We have here analyzed levels of glycoalkaloids (α-chaconine and α-solanine) and calystegines (A₃, B₂, and B₄) in potato tubers subjected to mechanical wounding, light exposure, or elevated temperature: stress treatments that are known or anticipated to induce glycoalkaloid levels. Basal glycoalkaloid levels in tubers varied between potato cultivars. Wounding and light exposure, but not heat, increased tuber glycoalkaloid levels, and the relative response differed among the cultivars. Also, calystegine levels varied between cultivars, with calystegine B4 showing the most marked variation. However, the total calystegine level was not affected by wounding or light exposure. The results demonstrate a strong variation among potato cultivars with regard to postharvest glycoalkaloid increases, and they suggest that the biosynthesis of glycoalkaloids and calystegines occurs independently of each other.

English

Typically, potato production has a high level of asset specificity and uncertainty, which are the major causes of transaction cost. The South African table potato market is associated with the spot market governance whereas the processing potatoes mainly make use of the more hybrid format of contracting. The aim of this study was to assist potato processing companies in South Africa to establish long-term relationships with producers and also to reduce producers’ transaction costs. Questionnaires were used to determine the magnitude of transaction costs within the potato industry. Interviews were held with the managers of five successful alliances within the potato industry in order to establish if the alliance assisted in overcoming market obstacles and what elements should be in place in order to build a successful long-term relationship with their buyer. The spot market and the contract market within the potato industry were compared in terms of transaction costs. The results indicated that the contract market had the lowest transaction costs. The results indicated that by forming an alliance, producers were able to overcome the obstacles they faced and the elements which should be in place were sound administration, trust and loyalty, market research, marketing and traceability. Key words: Transaction cost theory, potato marketing, contracts, marketing power, farmer alliances.

Nitrogen and phosphorus leaching losses from potatoes with different harvest times and following crops

A 3-year field study (2007–2009) was conducted in separately tile-drained plots on a sandy soil in south-west Sweden to determine nitrogen (N) and phosphorus (P) leaching losses from potatoes to the drainage system. Different types of potatoes were grown and harvested at different times followed by different crops in order to identify the potato type/following crop system with the lowest risk of N and P leaching losses. Accumulated annual amounts of N and P lost to drainage between May (potato planting) and the following April varied between 13 and 72kgNha−1 and 0.04 and 0.24kgPha−1 depending on treatment and year. P leaching losses from this particular soil were low and differences between potato types not distinct, but there were significant differences between years. Abnormally high precipitation in summer 2007 led to significantly higher P leaching losses than in other years. N leaching losses were also higher in 2007, but differences between potato types were found in all years. Despite the high mineral soil nitrogen content (Nmin) after harvest in June, early potatoes (EP) with oilseed radish (oil) as catch crop showed the lowest N leaching losses of all potatoes. Potatoes harvested in August (table potato; TP) and September/October (late potato; LP) followed by triticale (tri) sown in October showed the highest leaching losses. Thus under current climate conditions in Sweden, oilseed radish after EP is a suitable catch crop for N, while triticale sown in October is ineffective in preventing N leaching after potatoes. The late harvest of starch potatoes (SP) did not allow establishment of a following crop. However, SP showed lower N leaching losses than TP+tri and LP+tri due to lower residual Nmin in deeper soil layers, low temperatures after harvest decreasing soil N mineralisation and higher C:N ratio of the potato haulm leading to lower N mineralisation potential. As a mean of all years, N leaching losses during and after EP+oil and SP were similar to those from the reference crop spring barley (SB), whereas TP+tri and LP+tri require countermeasures against N leaching.

Cultivar Variability of Patatin Biochemical Characteristics: Table versus Processing Potatoes (Solanum tuberosum L.)

Biochemical characteristics of patatin proteins purified by ion-exchange and affinity chromatography from tubers of 20 potato cultivars were studied to evaluate their genotype differences with respect to utility groups, table potato cultivars (TPCs) and processing potato cultivars (PPCs). Both groups of cultivars showed similar values of protein content in dry matter (3.98-7.39%) and of patatin relative abundance (5.40-35.40%). Three mass levels (∼40.6, 41.8, and 42.9 kDa) of purified patatins were found by MALDI-TOF MS within all cultivars. Differences among mass levels corresponding with the mass of sugar antenna (∼1.2 kDa) confirmed the previous concept of different glycosylation extentsin patatin proteins. It was showed that the individual types of patatin varying in their masses occur in the patatin family in a ratio specific for each of the cultivars, with the lowest mass type being the major one. Electrophoretic analyses demonstrated wide cultivar variability in number of patatin forms. Especially 2D-PAGE showed 17-23 detected protein spots independently on the utility group. Specific lipid acyl hydrolase (LAH) activity of purified patatins from the individual tested cultivars varied between 0.92 and 5.46 μmol/(min mg). Patatin samples within most of the TPCs exhibited higher values of specific LAH activity than samples of PPCs. It may be supposed that individual patatin forms do not have similar physiological roles.

Crude Protein Content in Diploid Hybrid Potato Clones of Solanum phureja–S. stenotomum

Breeding potato (Solanum tuberosum L.) with high protein content is important for food value and for the processing sector to extract protein from potatoes. Due to the narrow genetic base of the common potato, a new germplasm has to be explored for breeding high-protein potatoes. The objectives of this research were to quantify the crude protein content of diploid hybrid Solanum phureja–Solanum stenotomum (PHU-STN) genotypes, determine the correlation of crude protein content with dry matter and other important agronomic traits, and estimate broad sense heritability for crude protein content. In 2008 and 2009, 70 diploid clones were grown in replicated field plots in Jiagedaqi, Heilongjiang. Also, two tetraploid potato cultivars, Kexin 2 (table potato) and Atlantic (high dry matter), were included in this experiment as controls. The crude protein content on a fresh weight basis (FW) over replications and years for PHU-STN clones ranged from 2.85% to 5.01% with a grand mean of 3.72%, and most of these clones were significantly or highly significantly higher in crude protein content than the two tetraploid controls. Correlations between crude protein content and agronomic traits were all negative, but the magnitudes were generally weak or moderate. Therefore it should be possible to select diploid clones with high crude protein content and acceptable agronomic traits. The estimate of broad sense heritability for crude protein content (FW) on a clonal mean basis was 0.66 with a 95% confidence interval of 0.46 to 0.79, whereas for crude protein content on a dry weight basis the estimate of broad sense heritability was 0.65 with a 95% confidence interval of 0.43 to 0.78. These results suggest that these diploid hybrid PHU-STN clones would be a good germplasm source for a high-protein-breeding effort, and identification of tetraploid progenies with high protein content and acceptable agronomic traits from 4x–2x cross should be possible.

Potential use of insecticides and mineral oils for the control of transmission of major aphid-transmitted potato viruses

Viruses occurring in Serbia and other countries in the region are a huge problem constraining seed potato production. At lower altitudes, in lowland and hilly regions, where table potato production is widely distributed, more than 50% of healthy plants become infected with potato virus Y during one growing season. Under these conditions, seed potato production is hindered due to a high infection pressure of potato virus Y which spreads far more rapidly compared to leaf roll virus, virus S and other viruses hosted by this plant species. This study tended to clarify a frequent dilemma regarding the use of insecticides in preventing the infection of healthy plants with potato virus Y and leaf roll virus, given the oral and written recommendations from pesticide manufacturers, agronomists and scientists in the field of crop protection arising from a logical conclusion that aphid vector control results in virus transmission control. The present findings, which are in agreement with reports of authors from other countries, show that the use of insecticides is ineffective in preventing potato virus Y which is nonpersistently transmitted by aphids from an external source of infection. However, insecticides can exhibit efficacy in preventing potato virus Y transmission from infected plants to healthy plants within a crop, which can have an overall positive effect only if seed potato is grown in areas that have no external source of infection. The present results and those of other authors show that insecticides are effective in preventing the infection of healthy plants with persistently transmitted leaf roll virus. Mineral oils provide effective control of potato virus Y by preventing the infection of potato plants with the virus. They can be combined with other management practices to protect seed potato crops against the virus. Given the fact that the initial first-year infection of healthy potato plants with virus Y in relation to leaf roll virus is approximately 10-20:1 under conditions in Serbia, and that the use of insecticides fails to ensure protection against PVY, this practice cannot have any positive effect on virus control under high infection pressure conditions.

Cool Farm Tool – Potato: Model Description and Performance of Four Production Systems

The Cool Farm Tool – Potato (CFT-Potato) is a spreadsheet programme that allows the calculation of the amount of CO2 equivalents that it costs to produce 1 t of potato. The spreadsheet was adapted from an original generic version of the tool, and completed for potato production in diverse production areas in the world applying different levels of technology. The CO2 embedded in chemicals during their production and released from the soil after nitrogen fertilization in the CFT-Potato has been updated to consider more recent products and production methods. Energy costs of the operations in the original version taken from generic data provided by the American Society of Agricultural and Biological Engineers Standard, however, were altered (usually increased) where there was evidence from practical sources that the original figures did not apply. For example, the figure of around 16 l of diesel per ha for potato harvesting in the original version was corrected to 60 l of diesel per ha based on observational data. Figures for typical potato operations such as windrowing were supplied. Irrigation with pumps powered by diesel or electricity from the grid, with a centre pivot, a rain gun, drip irrigation and flooding and energy cost for extracting water from deeper sources were also added. We added data for grading, washing, store loading and unloading, the application of a sprout suppressant and storage with ventilation of ambient air or forced refrigeration. The CFT-Potato can be used by growers to calculate the actual costs of 1 t of potato in terms of kilograms CO2 and explore the repercussion of altered management options. Here the comparison of four potato production systems in the Netherlands is shown: seed potatoes (115 kg CO2/t), table potatoes (77 kg CO2/t), starch potatoes (71 kg CO2/t) and organic potato (82 kg CO2/t). Based on potato dry matter, however, starch potato has the lowest footprint mainly due to the extensive use of pig slurry of which the production and transport CO2 costs are attributed to the pig production chain.

Химический состав столового картофеля в зависимости от внекорневых обработок регуляторами роста растений и гуминовыми удобрениями

Изучено действие регуляторов роста растений и гуминовых удобрений при выращивании столового картофеля на химический состав растений. Установлено, что они способствуют изменению макро- и микроэлементного состава в ботве и клубнях картофеля, снижению содержания тяжёлых металлов в клубнях картофеля на 17 - 39 %.

Glycoalkaloid Concentration in Potato Tubers Related to Storage and Consumer Offering

Steroidal glycoalkaloids (SGA) are unwanted potato constituents for consumers because they are highly toxic and therefore have to be controlled in the food chain. Three experiments were carried out focusing on storage aspects and on exposure to artificial light at the point of sale. The experiments showed that an elevated temperature (10 °C) during long-term storage without sprouting inhibitors led to an increase in SGA contents (up to 518 mg SGA kg−1 dry matter) in two of three investigated cultivars independent of the sprouting level. Cold storage (4 °C) slightly enhanced SGA contents in two cultivars. Sprout control resulted in a tendentious decrease in SGA contents in a set of another three cultivars. Growing location and wet and cool seasons had an influence too. Moderate exposure to light resulted in an increase in SGA in autumn, but in a decrease in spring time. Again, cultivars tested responded differently. The addressed factors have to be considered when developing strategies in minimising SGA level in table potatoes.

Influence of growth regulators on skin colour and scab diseases of red-skinned potatoes

A uniform dark red skin colour is desirable in table potatoes; however, the colour of the popular red-skinned cultivar Norland is variable and tends to fade during storage. This study evaluated the potential to enhance skin colour of red potatoes by foliar application of the auxin-type herbicide 2,4-D or long-lasting analogs of the naturally occuring hormone abscisic acid (ABA). In field trials conducted from 2007 to 2009, the plant growth regulators (PGR) were applied to the foliage of Norland and AC Peregrine Red (a new dark red variety) potato plants when the crop was at the tuber set stage. Although the 2,4-D treatments altered the appearance of the foliage they had no consistent impact on yields or tuber shape, but did reduce the average tuber size. Objective and subjective assessments indicated that the 2,4-D treatments altered the skin colour of the tubers both immediately after harvest and after extended cold storage. The degree and nature of the colour change was somewhat dependent on the year, the rate of 2,4-D applied and the cultivar. The change in tuber appearance arising from the 2,4-D treatments was not always considered desirable by consumer panellists. The 2,4-D treatments also reduced tuber damage by common scab (Streptomyces scabies), but tended to increase grade out to powdery scab (Spongospora subterranea). The ABA analogs had no consistent impact on yields, skin colour or disease reaction. Key words: 2,4-dichlorophenoxyacetic acid, abscisic acid, common scab, powdery scab, Streptomyces scabies, Spongospora subterranea

Herbicide Residues and Nitrate Concentration in Tubers of Table Potatoes

This study examined Wiking-cultivar table potato tubers in a field experiment conducted between 2002 and 2004 using a rye complex soil. The experimental factors included (a) two methods of tillage, including traditional and simplified, as well as (b) seven methods of cultivation with the use of herbicides as follows: 1, control without herbicides; 2, Plateen 41.5 WG; 3, Plateen 41.5 WG + Fusilade Forte 150 EC; 4, Plateen 41.5 WG + Fusilade Forte 150 EC + adjuvant Atpolan 80 EC; 5, Barox 460 SL; 6, Barox 460 SL + Fusilade Forte 150 EC; and 7, Barox 460 SL + Fusilade Forte 150 EC + adjuvant Atpolan 80 EC. Determination of residues was performed using high-performance liquid and gas chromatography. Only trace quantities of bentazone (Barox 460 SL) were found in potato tubers, amounts that fell below the maximum residue limit (MRL). The nitrate content of potato tubers was determined using a nitrate ion-selective electrode and silver chloride reference electrode. The nitrate content in fresh matter of unpeeled and peeled tubers depended significantly only on weather conditions in the years of study. In contrast, agrotechnical procedures such as methods of tillage and cultivation did not significantly affect potato tuber nitrate content.

Uncertainties in the carbon footprint of food products: a case study on table potatoes

Background, aim, and scope Carbon footprint (CF) has become a hot topic as public awareness of climate change is placing demands on manufacturers to declare the climate impact of their products. Calculating the CF of food products is complex and associated with unavoidable uncertainty due to the inherent variability of natural processes. This study quantifies the uncertainty of a common food product and discusses the results in relation to different types of CF systems for food product labelling.

THE INFLUENCE OF UNDERSOWN CROPS AND STRAW BIOMASS ON YIELD AND NUTRITIONAL VALUE OF POTATO TUBERS

The paper presents the results of research carried out over 2001-2003 which aimed at describing the influence of undersown crops and spring barley straw fertilization on chemical composition of table potato tubers. Two factors were examined. I - undersown crops fertilization: control variant (without undersown crops fertilization), farmyard manure, black medic (Medicago lupulina), black medic (Medicago lupulina) + Italian ryegrass (Lolium multiflorum), Italian ryegrass (Lolium multiflorum). II – straw fertilization (subblock without straw, subblock with straw). Obtained results allow to conclude that, fertilization with mixture of black medic with Italian ryegrass and black medic in combinations without straw or with straw in terms of size and quality of yield of potato tubers it equals or it even exceeds the farmyard manure fertilization. The increase of starch, vitamin C and true protein content in comparison with control variant was noted in potato tubers fertilizerd with undersown crops biomass and straw.

UTILIZATION OF DNA MARKERS BASED ON MICROSATELLITE POLYMORPHISM FOR IDENTIFICATION OF POTATO VARIETIES CULTIVATED IN THE CZECH REPUBLIC

In the year 2007, there were one hundred and seventy-eight potato varieties enlisted in the Czech list of registered potato varieties. The classical morphometric approach to characterization is not effective for such a number of varieties especially for identification at the level of tubers. The needfulness of variety identification at the level of tubers is important mainly for trade aspect. The Czech law no.110/1997 Sb. about the food-stuff and tobacco products and the consequential ordinance (MZe č. 332 / 1997 Sb.) require guarantee of variety declaration in commercial relation for table potato. In this study we analyzed twenty potato varieties (Solanum tuberosum L.) cultivated in the Czech Republic. Every variety was represented by four independent replicates. This set of samples was analyzed by methods of PCR-SSR (Simple Sequence Repeats) and PCR-ISSR (Inter Simple Sequence Repeats). We discovered that both of tested methods afford sufficient polymorphism for variety identification, but the method of PCR-ISSR is not utilizable, because we observed the variability within variety. For outright identification of the whole set of potato varieties cultivated in the Czech Republic we recommend to use SSR, AFLP and retrotransposene-based markers as well as morphological markers.

Risk assessment for volunteer and seedling GM potatoes in the northernmost European growing areas

Commercial production of genetically modified (GM) potatoes (Solanum tuberosum L.) could represent a risk to conventional production if volunteer plants develop from tubers or true seeds that survive until the following growing season. We studied such risks under northernmost European conditions and monitored the effects of cultivar, tuber size and tuber depth in the soil on winter survival at MTT Agrifood Research Finland, Jokioinen (61°06′N, 23°02′E) from 2004–2007. Tubers of two non-GM cultivars, Saturna and Asterix, and two size classes, 25–30 mm and 45–50 mm, were planted at depths of 10 and 20 cm in autumn, soon after harvest. In winters 2004–2005 and 2005–2006 all tubers planted in the soil in autumn were killed by frost. In 2005–2006, the field was covered by up to 30–40 cm of snow and the minimum soil temperatures ranged between −0.4oC and −0.9oC, but only 0.0–3.5% of the tubers survived and there was no difference between cultivars, tuber sizes and planting depths. Under laboratory conditions compared with −2.0°C and −2.5°C, treatment at −3.0°C for 72 h resulted in significantly lower survival rate of the tubers (8.2%). Asterix, a late maturing table potato cultivar, was more resistant to low temperatures than the processing cultivar Saturna. In general, volunteer tubers are not currently a significant risk for coexistence of GM and conventional potato production in northern Europe due to the cold winter conditions but also due to possibilities to control the sporadic volunteers from the next crop. However, we noted that seedlings initiated from true potato seed are able to produce tubers despite the short growing season. Such a risk could be reduced by accepting only non-berry-producing GM cultivars for cultivation.

Phenotypic and Genotypic Changes in the Phytophthora infestans Population in Taiwan – 1991 to 2006

AbstractLate blight, caused by Phytophthora infestans, is one of the most destructive diseases of tomato in Taiwan. A total of 655 isolates of P. infestans, including 29 isolates from potato, was collected from major tomato and potato production areas of Taiwan during 1991 to 2006. Isolates were characterized for their pathogenicity, mating type, in vitro metalaxyl sensitivity and molecular genotype (including allozyme pattern, mitochondrial genomic haplotype and DNA fingerprint) to monitor population changes in P. infestans. The population of P. infestans in Taiwan underwent a dramatic genetic shift in the 1997–1998 cool growing season. Isolates collected from tomato before 1997 were aggressive to tomato but not potato; most isolates obtained after 1998, were aggressive to both hosts. Metalaxyl sensitivity of isolates changed from sensitive/intermediate before 1997 to resistant since 1998. Similarly, the isolates obtained before 1997 were all US‐1 clonal lineage (including variants US‐1.1, US‐1.2, US‐1.3 and US‐1.4). During the 1997–1998 cool growing season, the US‐11 clonal lineage and the TW‐1 genotype appeared, possibly introduced on imported table potatoes. The US‐11 lineage spread rapidly and since 1999 has almost completely displaced the old population in Taiwan. Mating type determined by pairing with A1 and A2 reference isolages of P. parasitica, showed all isolates were of the A1 mating type, suggesting that the A2 mating type had not become established in Taiwan. The increasing percentage (up to 42.3% in 2006) of the US‐11 variants (including US‐11.l, US‐11.2, US‐11.3 and US‐11.4) implied that genomic diversity of the pathogen is changing quickly. Therefore, it is important to continuously monitor the population changes of P. infestans and develop an integrated management strategy for this disease.

Patatin, the major protein of potato (Solanum tuberosum L.) tubers, and its occurrence as genotype effect: processing versus table potatoes

Patatin relative abundance in SDS-extractable protein and patatin content in dry matter were evaluated in tubers of forty processing and table potato cultivars usually cultivated in the Czech Republic, Germany, and the Netherlands. The patatin characteristics were evaluated over three experimental years. Patatin relative abundance in the processing cultivars achieved on average a significantly higher value (<I>P</I> < 0.001; Tukey HSD test) than patatin relative abundance in the table cultivars, resulting in average values of 25.80% and 21.59%, respectively. A high patatin relative abundance (over 30% in extractable protein) was determined only in the case of two cultivars: Vaneda (average 31.29%) and Tomensa (average 31.24%). Patatin content in tuber dry matter was significantly higher in the processing potato cultivars in all three experimental years (<I>P</I> < 0.001), attaining a mean of 1.28% with the processing cultivars and 1.03% with the table cultivars. The direct effect of the cultivar on patatin relative abundance in SDS-extractable protein was higher (33.1% for processing potato cultivars and 48.1% for table potato cultivars) than the effect of the growing year (15.6% for processing potato cultivar and 22.8% for table potato cultivars).

AN ALTERNATIVE DEAL FOR POTATO GROWERS IN A CONTRACT FARMING SYSTEM

At the present time there is much controversy over the equity of small-scale producers in the supply chain, especially in developing countries. It is widely believed that farmers in the Third World have difficulty in gaining market access. While contract farming is attributed as a direct mechanism to integrate small growers into the supply chain, the system has often been blamed as lacking advantages for growers. In particular, growers have a concern regarding fairness of the contracts they sign with food processors and their economic security after the termination of the contract. This paper aims to illustrate the significant change in farmers’ practice from being contracted farmers, to being non-contracted. This encourages potato growers to negotiate a better deal in order to participate in the potato supply chain, as well as creating access to public sector support by small scale farmers. Furthermore, the positive outcome of the contract farming system is also presented. Potato growers in the San Sai District of Chiang Mai Province in the northern region of Thailand, have cultivated table potatoes since the 1960s. When processing potatoes were first introduced into San Sai District in 1987, potato growers had been acquainted with the contract system. At the initial stage, the firms made contracts with the farmers’ group and provided financial support and knowledge on potato production, which benefited growers directly. However, in 2001 the contracts were terminated due to various changes. Driving forces behind these changes were: the rapid increase in demand for potato chips, technical innovations, and continuous support from various government agencies in terms of research and development. The key consequences of the changes impacted on the functioning and performance of the market and better farm gate prices, lower production costs, and higher income from rotation cropping systems for farmers, as well as better soil conservation practices.

Tomato severe rugose virus: Another Begomovirus Causing Leaf Deformation and Mosaic Symptoms on Potato in Brazil.

Over the past 10 years, Tomato yellow vein streak virus (ToYVSV) has been a major begomovirus in the main solanaceous crop region of Campinas, São Paulo, which includes counties of Sumaré, Monte Mor, Elias Fausto, and Indaiatuba. The top leaves of potato plants (Solanum tuberosum) having deforming mosaic symptoms (dms), which includes a yellow mosaic or mottling on distorted and deformed leaflets, were associated with this geminivirus (4). Recently, a table potato crop (cv. Agata) from Sumaré, with a record of a few or no white flies (Bemisia tabaci), during the winter season of June to September 2006 had 5 to 7% dms, suggestive of seed potato tuber borne virus infection. Double-antibody sandwich (DAS)-ELISA for Potato virus Y (PVY), Potato leaf roll virus (PLRV), Potato virus X (PVX), and Potato virus S (PVS) (SASA kits and protocols, Edinburgh, Scotland) gave negative results for four field collected potato plants showing dms. Bioassays (mechanical transmission from potato leaf extracts in phosphate buffered saline, 1:5 w/v) with test plants of Nicotiana tabaccum cvs. Turkish and TNN, Gomphrena globosa, Chenopodium quinoa, Datura metel, Solanum tuberosum, and a Physalis sp. were all negative. Inoculated D. stramonium developed symptoms resembling ToYVSV infection including vein clearing and mild mottling on new leaves 2 to 3 weeks postinoculation. Using primers PAC1v1978/PAV1c715 for begomovirus detection (3), the predicted PCR amplified fragment of 1,320 bp was obtained from leaf DNA extracted from all four of the dms field potato plants, as well as the inoculated and symptomatic D. stramoniium test plants. Sequence analysis indicated 100% nt identity among the 1.3-kb PCR fragments obtained from potato and D. stramonium infected plants. Sequences of 96 cloned amplicons (pGEM-T Easy Kit; Promega, Madison, WI) from symptomatic plants in the Sumaré potato field were 98 to 99% identical to Tomato severe rugose virus (ToSRV). BLAST analysis of a consensus sequence (Sequencher 3.1; Gene Codes Corporation, Ann Arbor, MI) revealed more than 95 and 99% identity with ToSRV isolates from Uberlandia (Accession No. AY029750) and Goias (Accession No. DQ207749), respectively. The DNA-based phylogenetic dendrogram confirmed the highest similarity with ToSRV and the lowest similarity with ToYVSV (72%), which was located in another cluster. These results indicate that ToSRV was the causal agent producing dms in potato plants from Sumaré. Therefore, similarly to ToYVSV (4), potato dms can be caused by ToSRV. Preliminary tests revealed that ToSRV was transmitted via seed tubers. Thus, it is of concern for seed potato certification in Brazil, especially in the major seed-potato-producing state of Santa Catarina where an outbreak of ToSRV was recently reported in tomato crops (1). Although ToSRV has been identified in other solanaceous crops in Brazil, especially tomato (Lycopersicon esculentum) and sweet pepper (Capsicum annum) (2), to our knowledge, this is the first report of ToSRV in potato in Brazil. Reference: (1) A. T. M. Lima et al. Fitopatol. Bras. 31:224, 2006. (2) D. N. Nozaki et al. Summa Phytopathol. 33:93, 2007. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993. (4) J. A. C. Souza-Dias et al. CultivarHF 5(26):22, 2004.