Main Potato Research Articles

High-performance thin-layer chromatographic determination of potato glycoalkaloids

A high-performance thin-layer chromatographic (HPTLC) method for the determination of the two main potato glycoalkaloids, α-chaconine and α-solanine, in different parts of the potato plant, is described. Samples were extracted with diluted aqueous acetic acid containing the ion-pairing reagent 1-pentanesulfonic acid, sodium salt. Extracts were purified and analytes fivefold concentrated by a solid-phase extraction (SPE) procedure using a Sep-Pak C 18 cartridge. The methanol SPE eluate was applied to the HPTLC silica gel 60 F 254 plates. The separation was performed in chloroform–methanol–2% aqueous NH 4OH (70:30:5) mixture as the mobile phase. Six different detection reagents: two modifications of the Dragendorff’s reagent, phosphomolybdic acid, paraformaldehyde–phosphoric acid, Ce(IV)sulfate–sulfuric acid and sulfuric acid–ethanol reagents were applied for quantification by densitometry. Fluorescence enabled detection of 10 ng of each alkaloid.

Effect of potato used as a trap crop on potato cyst nematodes and other soil pathogens and on the growth of a subsequent main potato crop

SummaryA field experiment in which main‐crop potatoes were grown every other year was conducted on a sandy soil from 1994 to 1999. The aim of the experiment was to control soil‐borne pathogens of potato with ecologically sound methods. Potato grown as a trap crop from the end of April to the end of June (8 wk) was used to control potato cyst nematodes (PCN) (Globodera pallida), and its effects on other important soil pathogens and on the growth of a subsequent potato crop were also assessed. Additional experimental treatments were a potato crop from which the haulm was removed and a green manure crop. Three potato cultivars with different degrees of resistance to PCN were grown as the main crop. Duplicate sets of the experiment were run concurrently.The PCN were effectively controlled by the potato trap crop. When a highly resistant potato cultivar was grown as a main crop after the trap crop, the post‐harvest soil infestation was very low. When a moderately resistant cultivar was grown after the trap crop the soil infestation also remained low. When the trap crop was alternated with a susceptible potato cultivar as a main crop, soil infestation increased slightly, but the degree of control when compared with no trap crop averaged 96%.Soil infestation with root‐knot nematodes (mainly Meloidogyne hapla) increased when potato was grown as a trap crop, but soil infestation with the root‐lesion nematode Pratylenchus crenatus was not affected. Stem canker caused by Rhizoctonia solani was not affected by the trap crop but black scurf (sclerotia of R. solani) on tubers was reduced. Soil infestation with Verticillium dahliae declined in one of the duplicate sets of the experiment but not in the other. However, stem infections by V. dahliae were significantly decreased in both sets, although the effect depended on the PCN‐resistance level of the potato cultivar. When a highly resistant potato cultivar was grown Verticillium stem infections were not significantly affected, they were decreased with a moderately resistant cultivar but the decrease was most pronounced with a PCN‐susceptible cultivar.Senescence of a following potato crop was not influenced by the trap crop when a highly PCN‐resistant cultivar was grown, but it was delayed in the case of a moderately resistant or a susceptible cultivar, resulting in higher tuber yields for those cultivars.The experiment proved that a trap crop can be an alternative to chemical soil disinfection but, for several reasons, the potato itself is not an ideal crop for this purpose; a trap crop other than potato must be developed.

Comparison of alternative pest and soil management strategies for Maine potato production systems

AbstractPotato acreage and total production in Maine have declined steadily since the 1960s. In 1991, a University of Maine research team established a large-scale, long-term, comparative study of three factors that form the foundation of productive potato cropping systems: soil management, pest management, and variety choice. This study, the Potato Ecosystem Project, included 96 main plots (5.8 ha total) and near-by “component studies.” The project contrasted amended vs. unamended soil management strategies; conventional vs. reduced-input vs. bio-intensive pest management strategies; and disease and stress susceptible vs. tolerant potato varieties. Given recent concerns over resistance to pesticides and increasing costs of agricultural chemical inputs, the reduced-input and bio-intensive pest management systems provided encouraging results. Weed growth was similar in the conventional and reduced-input systems. Colorado potato beetle thresholds were exceeded less often and their densities were lower in the bio-intensive system than in the reduced-input and conventional systems. Lady beetles, which are major aphid predators, were more abundant in the bio-intensive pest management system compared with the reduced-input and conventional systems in 5 of the 6 years. Tuber yield and quality were maintained at a high level in the reduced-input system, although difficulties with plant disease, nutrient and weed management contributed to significantly lower yields in the bio-intensive pest management system. Economic analysis indicated that from 1993 to 1996, the reduced-input system had a greater return over variable cost (avg. $973 ha-1) than the conventional (avg. $890ha-1) and bio-intensive pest management systems (avg. $578ha-1). The amended soil management system achieved rapid improvements in soil quality: soil organic matter, water stable aggregates, potassium, and soluble inorganic phosphorus contents increased while requirements for synthetic fertilizers were reduced. These improvements in soil quality enhanced late-season crop vigor, canopy duration and tuber quality, and increased yields by 13% and 30% over the unamended system in 1994 and 1995, respectively, but not in 1996. Improved crop vigor in the amended soil management system also benefited weed control efforts by encouraging a more weed-suppressive potato crop. In the biointensive pest management system, in which weeds were controlled mechanically, the amended soil management system had less weed biomass than the unamended soil management system in 1994 and 1995. Conversely, the amended soil management system consistently increased flea beetle populations and, in one of two years, the incidence of Rhizoctonia. The choice of potato variety also affected pest dynamics. Total aphid density (all aphid species considered together) and almost all disease ratings were higher on ‘Superior’ than ‘Atlantic’ potato.

Aspects of insecticide resistance and reproductive biology ofAphis gossypii glover on seed potatoes

For several years the aphid population patterns and the incidence of the main potato virus diseases have been monitored in Italian potato-growing areas. Starting from 1992, an increase inAphis gossypii, as compared toMyzus persicae, Macrosiphum euphorbiae andAphis fabae, was observed on seed potato fields in the north of Italy.

Agricultural Structure Improvement Policy and Regional Characteristics of Potato Production in Hokkaido

The aim of the Agricultural Basic Law (1961) was to increase farm income by scale enlargement and farm mechanization. In Hokkaido, over the past three decades, upland farms were mechanized and management scale was enlarged. On the contrary, most farmers in Honshu (the main island) became part-time farmers. The law therefore affected the two regions in different ways.In Hokkaido, mechanization also made it possible to improve land productivity. Deep ploughing by tractors, which replaced horses, allowed more fertilizer input. Mechanization of pesticide and insecticide application helped to extend the growth period. This mechanization proved to be labor saving and brought about increased land productivity. The productivity increase was particularly visible in potato production. The yield per hectare has nearly doubled over thirty years.Tokachi and Abashiri are the two main potato growing areas in Hokkaido. Both areas, at the beginning of the mechanization phase, had showed the same land productivity. Through mechanization, Abashiri realized higher productivity increases than Tokachi. Tokachi shifted its emphasis from potato starch production to the production of potatoes for home culinary and for processing. Most of the varieties in Tokachi were changed to early-ripening ones. Farmers in Tokachi succesfully produced more profitable potatoes. Farmers in Abashiri, on the other hand, were obliged to remain in starch oriented production partly because of plant diseases which prevented the shift made in Tokachi. Potatoes for starch are slow growth and high yielding varieties. This case study of potato production in Hokkaido shows that high yielding varieties are not necessarily the most profitable. We should be careful to evaluate regional differences in land productivity.

Relationship of Verticillium Wilt with Pink-Eye of Potato in Maine

In 1988 and 1989, the effect of Verticillium wilt on the incidence and severity of pink-eye of potato was studied. Six cultivars and 12 advanced breeding lines (clones) of Solanum tuberosum with varying degrees of resistance to Verticillium wilt were selected. Entries were inoculated with either Verticillium albo-atrum, V. dahliae, or a combination of both species; the control was noninoculated. Significant differences in the severity of Verticillium wilt symptoms were found for different clones and pathogens, and there was a significant year-by-clone interaction. Veriticillium wilt symptoms were more severe in 1989 than in 1988. Pink-eye-infected tubers were found in all treatments, and the clones differed significantly in both incidence and severity of the disease. Significant positive correlations were found between the severity of Verticillium wilt with V. albo-atrum or the combination of species, and the incidence or severity of pink-eye. The incidence of pink-eye was enhanced by the presence of Verticillium, but the presence of Verticillium was not necessary for pink-eye to develop.

The impact of the mandatory seed law on Maine potato acreage, yield and price

A statistical analysis of the economic impact of Maine’s mandatory seed potato law was conducted. Results suggest that since the law was implemented, Maine potato yields increased, total Maine potato acreage decreased, Maine seed potato acreage increased, seed potato rejections from certification were reduced, seed potato prices increased, and commercial potato prices decreased. Attempts to estimate the impact on commercial potato quality were unsuccessful. The estimated impact of the Maine mandatory seed law on a typical 200-acre commercial potato grower was an average increase in profits of $14,700 per year since the law was implemented in 1981.

Changes in the distribution of phenylamide-resistant strains ofPhytophthora infestans (Mont.) de Bary in Ireland 1985–89

Phenylamide-based fungicides were reintroduced to the Irish market in 1985. Mixtures of phenylamides and mancozeb were recommended for no more than 3 sprays in potato late blight control programmes with the last systemic spray to be applied not later than 31 July. Samples of potato foliage infected withP. infestans were collected from the main potato growing areas in Ireland over a five-year period starting in 1985. Using the floating disc method, 11% of the crops sampled in 1985 were found to have phenylamide-resistant strains ofP. infestans present. The number of crops with resistant strains increased rapidly up to 1988 when 83% of the crops sampled had resistance. Factors affecting the distribution of resistance and the efficacy of a phenylamide-based spray programme are discussed.

Effect of phosphorus fertiliser on the yield of potato tubers (Solanum tuberosum L.) and the prediction of tuber yield response by soil analysis

Field experiments were conducted over 6 years at 33 sites throughout the main potato growing areas of South Australia to examine the effects of applied phosphorus (banded at planting), at rates up to 300 kg/ha, on the total yield and size distribution of tubers and to calibrate, in terms of total yield, 8 soil phosphorus extraction procedures (Colwell, Olsen, Bray 1, Bray 2, Mehlich no. 1, lactate, fluoride and total). Phosphorus application significantly (P< 0.05) increased total tuber yield at 16 sites. The mean relative yield for these responsive sites was 69.7% (range 37.4- 91.2%) compared with 97.5% (range 88.0-102.5%) for the non-responsive sites. Tuber size distributions were determined at 13 sites and, depending on site and cultivar, the yield of 80-450 g tubers for the highest yielding treatments represented from 64.2 to 93.7% of the total yield of tubers for those treatments. For each soil phosphorus extraction procedure the Mitscherlich and Smith-Dolby bent-hyperbola models and the Cate-Nelson separation were used to investigate the correlations between yield response and extractable and total phosphorus in the surface (0- 15 cm) soil samples and to calculate critical values. For loamy sand to sandy clay loam surface soils, the order of efficacy of soil tests based on the coefficients of determination (r2) calculated using the Mitscherlich and Smith-Dolby bent-hyperbola models was Bray 1 and Bray 2 > Olsen > lactate, Mehlich no. 1, fluoride and Colwell. The coefficients of determination ranged from 0.88 (Bray 1) to 0.64 (Colwell) for the Smith-Dolby bent-hyperbola model and from 0.86 (Bray 1) to 0.65 (fluoride) for the Mitscherlich model. Yield response was not correlated with total phosphorus concentration. Using the Smith-Dolby benthyperbola model the critical phosphorus values (s.e. in parentheses) were: 25.8(1.8), 40.9(2.6), l6.8(1.4), 13.9(1.0), 38.4(3.1), 24.2(2.9) and 35.1(3.0) mg/kg for the Bray 1, Bray 2, Olsen, lactate, fluoride, Mehlich no. 1 and Colwell methods, respectively. Yield deficits >20% were associated with phosphorus soil test values t 2 0 mg/kg (Bray 1 method) and P-sorption values >240 mg/kg. Rates of 48-73 kg P/ha banded at planting were required for 95% of maximum yield at the deficient sites. For acid coarse-grain sand surface soils, significant Cate-Nelson separations were obtained for the Colwell, Bray 1, Bray 2, Mehlich no. 1 and fluoride methods, the critical phosphorus values were 7.5, 7.0, 5.5, 6.5 and 8.0 mg/kg, respectively. The order of efficacy of the soil tests was Bray 2 (r2 = 0.66) >Bray 1, Colwell, Mehlich no. 1 and fluoride (all r2 = 0.55). Yield deficits >10% were associated with soil test values t 6 mg/kg (Bray 1 method). Rates of 27-59 kg P/ha banded at planting were required for 95% of maximum yield at the deficient sites. Data are presented which suggest that for similar soil types and extraction procedures critical values or critical concentration ranges may apply across a range of growing conditions, planting times and cultivars.

Effects of climatic conditions on intercepted radiation and some growth parameters in potato.

1982年から1986年まで北海道農業試験場で行った生育追跡試験の4品種のデータを用い, 植物体が受光した光合成有効放射量(ΔPAR), 受光量当たりの乾物生産効率(EPAR), 受光量に関連する生長パラメータおよび塊茎生長速度を算出し, それらのパラメータと気象要因との関係について検討した. 調査期間中の受光量は1984年が最大で, 1983, 85, 86年が小さい傾向を示した. 受光量当たりの乾物生産効率(EPAR)は, 1983, 84年が大きく, 82年で小さかった. また, 積算受光量と積算全乾物重の間には1次直線的関係があったが, 年次によって直線からの偏差がみられた. 個体群生長速度(CCR)は萌芽から6月30日までの期間, ΔPAR, EPARと有意な正の相関を示した. 7月以降ではCGRはEPARと高い正の相関を示した. また, 塊茎乾物増加速度(TGR)は, 生育期間を通じてCCR, EPARと有意な正の相関を示した. 生育前半, 葉乾物増加速度(LGR)およびTGRは気温, 特に最低気温と有意な関係を示し, 比葉面積(SLA)は日射量に関係しているものと考えられた. 塊茎形成期は水分ストレスに対して敏感で, 水分ストレスが働くと塊茎乾物重割合が大きくなる傾向があった. 生育後半, 気象要因が生長パラメータに及ぼす直接的な影響は認められなかったが, 生育終盤, 積算気温が大きいほど塊茎に対する地上部乾物重割合が大きく, 積算日射量が大きいほど地上部に対する塊茎の割合が大きい傾向があった.

Anastomosis Group 3 Is the Major Cause of Rhizoctonia Disease of Potato in Maine

Anastomosis Group 3 Is the Major Cause of Rhizoctonia Disease of Potato in Maine

Effect of application methods on movement and degradation of aldicarb residues in Maine potato fields

AbstractThe effect of application methods on movement and degradation of aldicarb residues was studied in a typically stony, Maine potato field by comparing aldicarb applied in‐furrow at planting with aldicarb top‐dressed at emergence. At the end of the growing season, residues from the at‐planting application were found primarily in the top 0.6 m of soil and the residues from the emergence application were found primarily in the top 0.3 m. One year later, the residues were dispersed throughout the top 1.5 m of soil and had been reduced to about 5% of the original application. This study supports other work that has demonstrated that in the northeastern United States and Wisconsin, early aldicarb at‐planting applications generally result in greater aldicarb residue movement than do later emergence applications.The study is also useful in illustrating variability of soil samples, which exhibited an average coefficient of variation of 110%. The results indicate that little information is lost due to compositing samples, so that compositing samples appears to be an option for reducing analytical costs associated with soil studies.

Changing a post-harvest system: Impact of diffused light potato stores in Sri Lanka

This paper presents a case study describing the initial transfer and impact of a new post-harvest technology in Sri Lanka. Conditions in the main potato producing regions in 1980 were conducive to rapid acceptance of low cost, diffused light seed storage. Due to rising costs of foreign seed, unavailability of seed at optimal planting times, heavy losses in handling and storage, government concern with foreign exchange and extension involvement, farmers became receptive to new methods for improving existing storage practices. This study of adoption and impact illustrates how improved post-harvest technology can have important consequences, not only in cutting storage losses, but in increasing yields, changing cropping patterns, reducing dependency on foreign seed imports and bringing prestige to agricultural research and extension programs.

Monitoring metalaxyl resistance in populations ofPhytophthora infestans

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.

Soil solution levels of nitrate nitrogen in a potato-buckwheat rotation

Using excessive rates of N fertilizer on potatoes in Maine has been a common practice. Excessive N did not significantly increase potato yields above the recommended N application. The impact of N fertilization upon soil solution levels of NO3-N in the B and C soil horizons was compared at three application levels of N. High N resulted in greater levels of NO3-N in the C horizon and the strong possibility of groundwater contamination. There was no apparent change in the NO3-N content of the C horizon during the winter following buckwheat, but there was an increase of NO3-N in this horizon when fall levels beneath potatoes were compared to spring values under buckwheat. After one year of no N application soil solution NO3-N levels in the B horizon returned to amounts that were the same as those receiving no N fertilization for a decade.

Effects of several microbial seedpiece treatments on emergence, yield, tuber defects, tuber size distribution, and specific gravity of Katahdin and Russet Burbank potatoes in Maine

Several microbial seedpiece treatments were applied to Katahdin and Russet Burbank to determine their effects on emergence rates, yield, tuber defects, tuber size distribution, and specific gravity under Maine conditions. None of the seedpiece treatments affected total yield, final plant stand, or specific gravity, although several treatments caused slight delays in rate of plant emergence. Several of the seedpiece treatments increased yield of small tubers of Russet Burbank and shifted the yield of Katahdin slightly toward the larger grade size classes. None of the microbial seedpiece treatments was substantially different in performance from the other treatments; and none can be recommended as beneficial for potatoes in Maine.

Forecasting Maine Potato Prices

Forecasting models were developed for annual and monthly average price of Maine potatoes, using Crop Reporting Board data. Several approaches to the forecasting problem were explored, as were a number of statistical aids to model development and evaluation. Attention was focused on providing timely forecasts as data became available.Specifically, three models were developed. The first provided forecasts of the season average price. Attention here was placed on the selection of a subset of influential variables from a set of potentially important ones, as well as the detection of outliers and colinearities. These problems were especially significant given the small number of observations in the annual price series. Production data for five regions were deemed most influential.The other two models were developed to provide forecasts of the monthly average price from November through May. A modified ARIMA (0,1,0) (2,1,0) model was estimated and used to provide forecasts based on the price data series alone. An alternate model, using production levels from four regions, current stocks levels and a monthly trend variable (and, implicitly, lagged price), was also developed.Both monthly models provided current forecasts for each month remaining in the marketing season which were updated as new information became available. The second model, which incorporated more information, was deemed to provide somewhat more accurate forecasts, at all forecast distances, than the simpler ARIMA model, when compared over the 1977–1981 period.

Potato chip color ratings of advanced selections from the Maine potato breeding program

Seven named varieties and three numbered selections from the University of Maine potato breeding program were compared for chip color at various conditions and lengths of storage. Although all selections tested were equal to or better than Kennebec in chip color, only Allagash Russet equaled Monona. Storage at 45° F (7.2° C) produced acceptable chip color at all time periods tested. After long term storage at 45° F, reconditioning at 55° F(12.8° C) was ineffective in improving chip color. Following storage at 38° F (3.3° C) acceptable chip color could be produced only by reconditioning at 70° F (21.1° C) for at least two weeks.

Symptoms and transmission of potato deforming mosaic of Argentina

Potato deforming mosaic (PDM), known since about 1950, is increasing in importance and nn the main potato growing area of Argentina it is numerically at least as important as potato leaf roll virus and virus Y. It has not been reported from other parts of the world.

Effect of Genotype and Tuber Size on Eye Number and Blind Seedpieces in Potato1

Samples of 60 to 200 tubers from each of 10 potato cultivars (Solanum tuberosum, L.) and six different unnamed clones from the Maine Potato Breeding Program were hand‐sized and the number of eyes per tuber ascertained. Eye number showed significant positive correlation with tuber size. Each of three size categories differed significantly from the other two in mean eye number. Although several clones and cultivars differed significantly in mean eye number, the relationship of eye number to tuber size was similar for all clones and cultivars tested.Larger samples of the six unnamed clones were sized and cut by machine. The percentage of blind seedpieces (pieces with no eyes) was then determined for the three tuber size categories. In general, larger tubers produced more blind seedpieces. Clones with low eye numbers produced four times as many blind seedpieces in all size categories as clones with high eye numbers.