The effects of handling on chip color and sugar content of potato tubers

Color of chips made from potatoes (Solanum tuberosum L.) subjected to handling treatments was darker than of non-handled tubers in nine of ten experiments. ‘Monona’ and ‘Rosa’ appeared to be more vulnerable to the adverse effects of handling than were ‘Kennebec’ and ‘Norchip,’ but all cultivars were affected. Levels of fructose and glucose were elevated by handling. Sucrose also increased in all cultivars except ‘Kennebec.’ The handling effect was most noticeable early (December) or late (March or April) in the storage season. The effect of chilling did not appear to be intensified by handling.     

Effect of plant population and harvest timing on yield and chipping quality of Atlantic and Norchip potatoes at two Iowa locations

The effect of plant population and harvest timing on potato yield and chipping quality was studied at two Iowa locations during 1986, 1987, and 1988. Evaluations were conducted in eastern Iowa near Muscatine and in western Iowa at Whiting. The cultivars Atlantic and Norchip were planted at in-row spacings of 15, 31, and 46 cm and were harvested approximately 12, 14, and 16 weeks after planting. Delaying harvest until 14 or 16 weeks after planting resulted in greater yields and better specific gravities for both cultivars. At Muscatine, chip color was not significantly affected by harvest date, but at Whiting, each successive harvest produced lighter-colored chips. Greater seed piece populations increased both Atlantic arid Norchip yields. Greater planting populations also caused a small increase in specific gravity. Seed spacing did not significantly affect chip color. In comparison with Norchip, Atlantic produced tubers with higher specific gravities throughout the season and greater total yields on the final harvest date. Atlantic did, however, show susceptibility to hollow heart. The incidence of hollow heart was reduced by close seed spacing.     

Effects of short periods of chilling and warming on potato sugar content and chipping quality

Two days of chilling (exposure to 1 C) had no detectable effect on chip color or sugar content of potato (Solanum tuberosum L.) tubers. Four days of chilling led to increases in sugars if potatoes were stored at 10 C or 19 C for 3 to 4 days after chilling ended. Longer chilling gave increases in sugars by the end of the chilling period, and returning tubers to 10 C or 19 C magnified the response. Glucose and fructose gave similar increases from chilling treatments, except that glucose levels were consistently greater. Sucrose was increased by chilling, but the response pattern did not always resemble that of the reducing sugars. Twenty-seven days of storage at 19 C after chilling lowered levels of reducing sugars late in the storage season but not in December. Cultivars differed in response to chilling. Kennebec tubers accumulated far more reducing sugars but much less sucrose than did Norchip tubers. Storage at 19 C after chilling lowered the sucrose content of Kennebec and Monona while raising that of Norchip.     

Reaction of potato varieties toPotato mop-top virus infection in the andes

The unexpected detection ofPotato mop-top virus (PMTV) in potatoes growing at several locations in the U.S.A. and Canada in 2002 has led to the realization that this soil-borne virus may be widespread throughout the potato-producing regions of both countries. A lack of information concerning the response of U.S. cultivars to PMTV infection caused us to examine the effects of PMTV on field-grown plants at three locations in the Peruvian Andes where the virus and its fungal vector,Spongospora subterranea, are endemic. All 21 U.S. cultivars tested proved susceptible to PMTV infection, especially at La Victoria where the overall incidence of both PMTV and powdery scab was high. Symptom expression in the foliage proved to be an unreliable indicator of virus infection, and thus, more reliable serological (NCM-ELISA) and nucleic acid-based techniques (NASH and RT-PCR) were used to monitor tuber tissue for the presence of PMTV. As much as 25% of field-grown tubers of cvs Kennebec, Monona, and Norland were infected with PMTV, but no correlation between virus infection and either the incidence or severity of powdery scab for any variety was apparent. Although PMTV infection did not result in the appearance of spraing or other internal necrotic reactions resembling those reported from many North American and European locations, a disproportionate proportion of infected tubers did exhibit a reticulate surface cracking. In hydroponic culture, the proportion of cracked tubers increased dramatically when the nutrient solution was seeded with virus-infestedS. subterranea. Comparatively few tubers of cvs Monona and Russet Burbank exhibited this surface cracking, suggesting that these two varieties may be somewhat tolerant to PMTV infection.     

Effect of variety and harvest date on tuber sugars and chip color

The major tuber sugars—glucose, fructose and sucrose — in tubers of the Red Pontiac, Kennebec and Monona potato varieties harvested five times during the 1970 growing season were determined quantitatively by a gas-liquid Chromatographic technique. Also, chips were made from tubers and chip color was measured objectively and reported as Rd values. Red Pontiac tubers produced the darkest-colored chips (Rd-15.5), and its tubers tended to accumulate the highest levels of the three sugars. The major difference between Monona, which produced chips with the lightest color (Rd-21.1), and Kennebec (Rd-19.5) was the very low level of glucose found in the tubers of Monona. Varieties produced chips lightest in color at the second (8/31) or third (9/15) harvest dates. Conversely, darkest-colored chips were obtained from each variety at the fourth harvest date (9/28). This was attributed to the cool, wet weather. Sugar content also varied during the harvesting schedule. Glucose content changed little until late in the season when an increase occurred. Fructose tended to decline until the final harvest when a distinct increase was obtained. Sucrose declined significantly through the third harvest, but changed little thereafter.     

Reinfection of potato seed stocks with potato virus S and potato virus X in Wisconsin

Reinfection of potato seed stocks with the potato viruses S (PVS) and X (PVX) varied with cultivar, virus, and grower. Rapid recontamination was observed for the cultivars Norgold Russet and Ontario with PVS and for the cultivars LaChipper, Norchip, and Norgold Russet with PVX. Recontamination was low for the cultivars LaChipper and Monona with PVS and for the cultivars Kennebec, Monona, Norland, and Superior with PVX. Survey results suggest that PVS and/or PVX can be eliminated from cultivars which appear to possess field resistance to infection, but that further evaluation of cultivars which are very susceptible to reinfection will be necessary.     

Some storage characteristics of potato cultivar Atlantic

The cultivars Atlantic, Kennebec and Katahdin were compared as to their storability and cooking qualities for the storage seasons 1974–75 and 1975–76. The studies show Atlantic was equal to Katahdin and Kennebec with regard to storability, except that at storage temperatures above 40°F (4.5°C) for 6 months, sprouting was excessive. Storage losses due to Fusarium tuber rots from natural infection were higher in Atlantic than either Katahdin or Kennebec. The processing quality for chips and French fries of Atlantic was equal or slightly better when compared to the other varieties tested.     

Effect of planting date and inoculum level on incidence and severity of powdery scab on potato

Summary Powdery scab incidence and severity was examined on six potato cultivars planted at two different dates in a naturally infested field. There were two sub-plots; one where seed was exposed prior to planting to spores ofSpongospora subterranea from scabby peels, which were then added to the furrow at planting, and another where seed was exposed only to natural inoculum within the field. The later planting data reduced incidence and severity, but there were no differences between sub-plots. All cultivars became infected, but ‘Rosa’ was the most susceptible and ‘Katahdin’ the most resistant. Contribution No. 1720, Department of Plant Pathology, The Pennsylvania Agricultural Experiment Station. Authorized for publication September 22, 1988 as Journal Series Paper No. 8007.     

Effect of tetrachloronitrobenzene (fusarex) on emergence and yield of potatoes. Part III. — Northeast

Foundation seed potatoes of Katahdin, Kennebec and Pungo varieties were treated with Fusarex dust at three dates during the 1966–67 storage season. In 1967 these treated seed potatoes were planted in uniform tests and compared with untreated and desprouted seed potatoes. Cooperators in Maine, Long Island, New Jersey, Pennsylvania and Connecticut planted the seed lots, recorded plant emergence, and obtained yield data. Initial emergence of Fusarex-treated and desprouted seed was delayed when compared with untreated seed except in Pennsylvania where both initial and final emergence of Pungo and Kennebec was improved by Fusarex treatment. Final emergence of January and March Fusarextreated seed of all three varieties was better than that of untreated and desprouted seed in Pennsylvania. At all other locations improvement of plant stand by Fusarex seed treatment was very erratic. The March Fusarex treatments resulted in an average yield equal to the untreated seed. Yield of tubers from chemically treated Katahdin seed was not significantly affected when compared with untreated seed at four of the five locations. November treatment of Kennebec seed with Fusarex adversely affected yields at three of the five locations. In Connecticut all Fusarex seed treatments reduced yields of Kennebec. Pungo seed treated with Fusarex produced yields in most cases that were not statistically higher than that of untreated seed.     

Variations in stolon length and in incidence of tuber roots among eight potato cultivars

The stolon length and percentage of tubers with tuber roots were compared for eight cultivars ofSolanum tuberosum L. over two growing seasons. Although stolon lengths varied considerably within cultivars, there were significant differences in the average stolon lengths among cultivars. The cultivars Norchip and Monona had the shortest stolons whereas Norland had the longest average stolons. The length of the stolon did not appear to be related to color type or time of tuber maturity. Since there was no significant difference in stolon length between years, stolon length appears to be a consistent genetic trait. There was no significant correlation between the stolon length and tuber size. The incidence of tuber roots also showed variation among cultivars, although there was significant variability between times of sampling. Recent studies have demonstrated that to maximize calcium uptake by tubers, the calcium must be placed around the tubers and stolons. Since stolon length determines the location of the tubers in the hill, the stolon length of different cultivars may need to be considered for fertilizer application, cultivation or hilling procedures. Thus, to get maximum benefit from supplemental calcium for Norchip and Monona, application would need to be made close to the main stem. However, in the other cultivars, the majority of the hill would have to be enriched in calcium to effectively supply calcium to the various tubers in the hill.     

Yield and relationships among tuber size,sucrose and chip color in six potato cultivars on various harvest dates

Cultivars were harvested biweekly for yield, weekly for sucrose determinations, and stored for chipping. At the last harvest Crystal was highest in total and marketable yield. Specific gravity was higher in Lemhi, Russet Burbank, and Norchip than in Kennebec, Crystal and Dakchip. Storage tests showed Norchip had superior chipping color to other cultivars. Dakchip had better color after short rather than after long-term storage, while the opposite was true for Kennebec and Russet Burbank. Lemhi and Crystal were marginal in color throughout storage. Sucrose (mg sucrose/g fresh tuber) expressed as a sucrose rating (SR) ranged from 1.2 to 11.9 among the various cultivars and harvest dates. Correlation between SR’s and tuber size within cultivars ranged from ?.91 to ?.97. Variability in sucrose content of immature tubers explained 70% of the variability in chip color among cultivars after storage from four to six months. Sucrose levels may be used to predict relative chipping quality of various cultivars after moderate to long-term storage if measured during early tuber development when differences in sucrose concentration are greatest among cultivars.     

Accumulation of mineral elements in tuber periderm of potato cultivars differing in susceptibility to common scab

Summary Concentrations of Ca, P, K, Mg, Al, Fe, Mn, Cu and Zn were determined in healthy tuber peelings of cultivars less (Karin, Santé and Symfonia) and more (Agria, Désirée and Tomensa) susceptible to common scab when grown at two sites that differed in the level of scab incidence. The accumulation of some elements was significantly influenced by site, year, cultivar, maturity and the age of tuber periderm. At both sites, Ca and P in periderm tissue declined but Mg increased during the growing season. The Ca/P ratios in tuber periderm of all cultivars greatly decreased 83 days after planting. Concentrations of mineral elements measured at harvest may not reflect conditions present during the infection period, and consequently may not be related to scab incidence or severity.     

Influence of chemical seed and soil treatments onVerticillium-induced yield reduction and tuber defects

Experiments were conducted in 1969 and 1970 to determine the influence of chemical treatments of seed pieces and soil on the development ofVerticillium wilt as measured by tuber yield increases and reduction in severity of tuber defects. The influence of storage onVerticillium-induced tuber defects was evaluated. Seed treatment chemicals tested included zinc ion maneb, maneb, maneb-chloroneb, Polyram, benomyl, and thiabendazole. Soil treatment chemicals included O-Diethyl (O-methyl-sulfinyl) phenyl phosphoro-thioate, disulfoton, phorate, carbofuran, aldicarb, ethyl 4 (methyl- thio)-m-tolyl isopropyl phosphor amidate, benomyl, and thiabendazole. Inoculated seed pieces and artificially infested plot areas were used the first year while the second year natural inoculum from a previous crop was the source of infection. Kennebec and Katahdin cultivars were tested in 1969 and Kennebec alone in 1970. Verticillium-induced yield reductions and tuber defects were more severe in all respects with Kennebec than with Katahdin. With Katahdin the only significant evidence of infection was stem end discoloration. Seed treatments, with the exception of benomyl or thiabendazole, which were erratically phytotoxic, resulted in consistent yield increases and reduction in pink eye severity. In 1969 seed treatment reduced stem end browning in Kennebec. Soil treatment with disulfoton, carbofuran, and aldicarb, both alone and in combination with seed treatments resulted in consistent yield increases with Kennebec. The seed piece and soil treatment combinations tested in 1970 appeared to have an additive effect on yield increase from combination treatments equivalent to the gain from soil treatment alone plus seed treatment alone. The nematicide soil treatment materials did not influence yield. Tuber stem-end browning and pink eye defects in Kennebec did not increase in severity over a five month storage period.     

Uniformity among virus-free clones of ten potato cultivars

Heat therapy and meristem tip propagation were used to develop two or three virus-free clones of 10 cultivars from the following sources: Epicure from British Columbia and Scotland; Katahdin, Kennebec, Keswick, Red Pontiac and Sebago from British Columbia and New Brunswick; Norchip from Alberta, Quebec and Washington; Norland from Alberta, British Columbia and North Dakota; Red La Soda from British Columbia, Nebraska and North Dakota; and White Rose from British Columbia and North Dakota. Tests prior to treatment showed that all but one of the stocks were infected with potato virus X and/or potato virus S but in only five of the ten cultivars were all clones infected with the same virus or viruses. Field trials with the virus-free clones, which extended over four years, showed that one of the Norchip clones produced fewer tubers per plant than two other clones in three years of the four years, but no consistent differences in yield or specific gravity of tubers were found among the clones of any of the 10 cultivars.     

Dakchip: A white-skinned chipping cultivar

North Dakota State University announces the name of a new potato to be called Dakchip. Dakchip is a medium maturing cultivar with chip quality quite comparable to Norchip but better than Kennebec. This new cultivar has round to oblong white skinned tubers and has an excellent plant type and growth. Dakchip is comparable to Kennebec in yield but higher than Norchip. Dakchip has moderate resistance to late blight but is susceptible to most potato viruses and some races of scab.     

Differential effect of delayed planting on soybean cultivars varying in susceptibility to bacterial pustule and wildfire in Korea

In 2009 and 2010, the effect of delayed planting on bacterial pustule (Xanthomonas axonopodis pv. glycines) and wildfire (Pseudomonas syringae pv. tabaci) in four soybean cultivars was evaluated in fields in Suwon and Naju, Korea. Soybean was planted on 15 May as the first (traditional) planting date; then, planting was delayed at approximately 15-day intervals (three times) after the first planting. In plots planted approximately 15 or 30 days after the traditional planting date, the disease incidence in highly (Saeolkong and Taegwangkong) and moderately (Pungsannamulkong) susceptible cultivars was significantly reduced under moderate disease pressure, but disease reduction in highly susceptible cultivars was sometimes diminished especially against bacterial pustule under high disease pressure. Altered planting date had no effect on disease incidence in the least susceptible (resistant) cultivar (Cheongja-3-ho), regardless of disease pressure. Consistent differences in disease occurrence were not observed between planting locations. The results from this study indicate that delayed soybean planting reduced the bacterial disease incidence and differentially affected resistant and susceptible cultivars. Thus, planting resistant cultivars at the optimal planting date is desirable, but in the case of susceptible cultivars, delayed planting could be considered along with application of other control measures such as agrochemicals.     

Effects of sulphur dioxide and nitrogen dioxide on fourSolanum tuberosum L. cultivars

The effects of sulphur dioxide (SO₂) and nitrogen dioxide (NO₂), singly and in combination, on the shoot growth of four potato cultivars differing in maturity classification (Solanum tuberosum L. ‘Superior,’ ‘Norchip,’ ‘Kennebec, rs ‘Russet Burbank’) were determined in controlled conditions. Plants were exposed to 0.11 ppm SO₂ and/or 0.11 ppm NO₂ for 24 hours a day for 7 or 14 days. There were no significant differences in leaf growth of ‘Superior’ or ‘Norchip’ plants at 7 or 14 days. Stem dry weight was significantly reduced in ‘Superior’ only after 14 days in the mixture. ‘Kennebec’ and ‘Russet Burbank’ plants had significantly less leaf area, leaf fresh weight, and leaf water content after 14 days of exposure to the mixture, but there was no significant change in dry weight. Specific leaf weight was significantly increased in the mixture treated plants of both cultivars. The two earlier maturing cultivars, ‘Superior’ and ‘Norchip,’ were less sensitive to the SO₂ and NO₂ combination than the two later maturing cultivars, ‘Kennebec’ and ‘Russet Burbank’.     

Effect of short- and long-term exposure of seed tubers to low temperatures on the growth and yield of five potato cultivars

Trials were conducted in Alberta with Norchip, Norland, and Russet Burbank and in Ontario with Kennebec, Russet Burbank, Norchip, and Superior tubers to determine their response to short-term exposure to air temperatures of 0, ?1, and ?5 C and to long-term exposure to ?1, 0, 1,2, and 3 C. Exposure of seed tubers to ?1 C from 6 hours to 5 days did not affect growth characteristics or tuber yield of any of the five cultivars studied. Long-term (October–May) exposure to ?1 C in one study severely reduced emergence and tuber yield of Norchip (P<0.05). While the marketable yield of Russet Burbank was also reduced (P<0.05) by this treatment, Norland was not affected. Tubers of all cultivars exposed to air temperatures of ?3 or ?5 C for longer than 24 hours were severely injured and were not planted in the field trials at either location. In Alberta exposure of seed tubers of Norchip, Norland, and Russet Burbank to ?5 C for 6 and 12 hours caused a reduction (not significant) in yield. In Ontario, long-term storage at 1, 2, and 3 C and in combination with short-term (2 weeks) exposure to 0 or 10 C had no effect on growth or marketable yield of Norchip, Russet Burbank, Superior, and Kennebec seed tubers.     

Wound-healing and the effect of soil temperature,cultivars and protective chemicals on wound-healed potato seed pieces inoculated with seed piece decay fungi and bacteria

The effect ofFusarium solani (Fsc),F. sambucinum (Fs),Erwinia carotovora subsp.atroseptica (Eca), andE. carotovora subsp.carotovora (Ecc) inoculated singly and in combination (FscFs, FscEca, FscEcc, FsEca, FsEcc, and EcaEcc) on wound-healed potato seed pieces of the cultivar Kennebec was studied. Potato seed pieces wound-healed for 5 days at 13 C and approximately 100% relative humidity, inoculated with Fsc, Fs, Eca, Ecc and their combinations, and incubated for 10 days at 9 C were protected from Eca, Ecc, and EcaEcc. When wound-healed potato seed pieces were inoculated with Fsc, Fs, Eca, Ecc, and their combinations and planted in soil maintained at 7, 10, 15, 20 and 25 C, wound-healing protected seed pieces from all pathogens and their combinations in seed pieces held for 10 days at 10 and 15 C. When seed pieces of cultivars Atlantic, Kennebec, Norchip, Russet Burbank and Superior were inoculated with Fsc, Fs, Eca, Ecc, and their combinations, different levels of protection were observed: Russet Burbank had the highest level of protection, Atlantic and Kennebec were intermediate, and Norchip and Superior were slightly protected. Dusting mancozeb on wound-healed seed pieces before inoculation with Fsc, Fs, Eca, Ecc, and their combinations increased protection against all pathogens and their combinations by 39% or more compared to the nonchemical control.     

Patterns of stem water potential in field grown potatoes using stem psychrometers

Summary The first large scale outdoor measurements of potato (Solanum tuberosum L.) stem water potential (SWP) usingin situ temperature-corrected stem psychrometers were performed on three cultivars common to Ontario, Canada (Atlantic, Monona and Norchip). Potato plants were examined under three soil water treatments which included rainfed, irrigated and stressed through the use of rain shelters. Cultivar variations in SWP under both irrigated and rainfed conditions were slight (P>0.05), although some significant (P<0.05) differences in mid-day SWP were evident, especially under conditions conducive to high atmospheric water demand. Under these conditions. cv. Atlantic maintained the lowest SWP with cv. Monona highest and cv. Norchip was intermediate. Few differences in pre-dawn SWP were detected between the three cultivars under well watered and rainfed conditions. Under low soil water, significant differences (P<0.05) were observed. The similar trend of Atlantic maintaining the lowest SWP with Monona the highest was consistent.