Leaching of french-fried potato strips

Potatoes with high-reducing sugar content taken directly from cold storage (4.5 C) and cut into 3/8-inch-square, 3-inch-long strips, were immersed in liquid nitrogen or dichlorodifluoromethane (?30.5 C or?79 C) for 3 to 15 sec and then leached for 5 min in water at 50 C. It was found that by using this method of freezing and leaching light colored strips could be finish-fried from Red La Soda, Russet Burbank, and Norchip varieties without conditioning. Finished-fries prepared by water-leaching only were usually too dark.     

Biotic interactions affecting potato production

Pest/pathogen interactions affecting potato production are reviewed. Many reported interactions in potatoes and other crops are best termed associations or interrelationships. True synergistics interactions can be expressed as Y = b₁ x₁ + b₂ x₂ + b₃ (x₁ x₂) + - b_n x_n + e in which Y is a measure of plant growth, b₁, b₂, b_n are constants, x₁, x₂, x_n are independent variables and e is the error term. Examples of interactions including pathogen vectors, and various interactions involving different viruses and biotic taxa and among biotic taxa (e.g., virus-virus, virus-fungus, fungusbacteria, and nematode-fungus) in potatoes are cited. It is included that important interactions do occur in potato production systems and that additional research is needed to identify unknown interacting factors and to elucidate mechanisms of those previously described. Particular needs exist for holistic or synoptic studies to identify the role of interacting factors in total crop management.     

Increase in phosphorylase activity during cold-induced sugar accumulation in potato tubers

Summary The accumulation of reducing sugars, sucrose and hexose phosphates in cv. Bintje and genotype KW77-2916 during storage at 2, 4, or 8°C was studied in relation to several catalytic activities. Bintje tubers accumulated sugars during storage at 2 or 4°C, whereas KW77-2916 showed reduced cold-sweetening at 2°C. The increase in glucose 6-phosphate and sucrose occurred concurrently and preceded the increase in reducing sugar concentration. Phosphorylase activity showed a strong interaction with temperature, storage duration and sugar accumulation in both genotypes. Invertase activity increased in Bintje concomitantly with the increase in reducing sugars, but this effect was less obvious in KW77-2916. The activities of other glycolytic and Krebs cycle enzymes showed no obvious correlation with sugar accumulation. It is suggested that the increase in phosphorylase activity acts as a triggering event in the sweetening of potato tubers during cold storage.     

Reducing sugar accumulation in progeny families of cold chipping potato clones

Two North Dakota breeding clones, ND860-2 and ND2221-6 accumulate very little reducing sugar in low temperature storage and will produce acceptably colored chips with little reconditioning. Progeny from diallel crosses of ND860-2, ND2221-6, Norchip and Kennebec were evaluated for reducing sugar and total sugar accumulation after 100 days of cold storage (3–4°C). Crosses of the North Dakota clones with Norchip or Kennebec produced families whose distributions were skewed towards the high parent with respect to reducing sugar values; about 2% had levels near the two low parents. Crosses between ND860-2 and ND2221-6 produced reciprocal families in which an average of 8% of the progeny had levels as low as these two parents.     

Factors affecting infection of potato tubers byAlternaria solani in Colorado

Potato tubers became infected byAlternaria solani at the time of harvest. Infection occurred only on wounded tubers irrespective of their depth in the soil. The presence of free moisture on unwounded tubers did not increase the incidence of infection, and immature unwounded tubers were not susceptible. Tuber infections may be reduced by allowing tubers to fully mature before harvest or possibly, by applying chemicals to the soil surface.     

Factors affecting the culture in vitro of potato meristem tips

Summary Meristem tips of an Italian cultivar were cultured in a modification of Murashige and Skoog's medium. Light spectrum and intensity affected rooting and vigour of plantlets. The best results were obtained with 4000-lux fluorescent lamps with a spectrum roughly similar to that of daylight but richer in red. Agar did not affect the proportion of explants rooting but changed the root system appearance. The presence of gibberellic acid was important for rooting. Rooting of plantlets cultured on liquid substrates devoid of gibberellic acid was not dependent on the size of the explants. Sometimes teratomata developed in liquid substrates and occurred together with a small downward pH shift, while the normal development was always accompanied by a stronger pH shift to acid values

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Zusammenfassung Es wurden einige Faktoren, die die Entwicklung von Meristemspitzen der Kartoffel beeinflussen, untersucht. Meristemspitzen des italienischen KultivarsRicciona di Napoli wurden auf einem abge?nderten Murashige & Skoog-Medium angezogen. Die Versuche wurden w?hrend fünf Monaten, September bis Januar, durchgeführt. Das Lichtspektrum beeinflusste Bewurzelung und Wuchskraft der Pfl?nzchen (Tabelle 1). Fluoreszenzlampen mit einem ann?hernd gleichen Spektrum wie das Tageslicht, aber reicher an roten Strahlen, ergaben die besten Resultate. Die Lichtintensit?t war ein sehr wichtiger Faktor für die Wuchskraft der Pfl?nzchen (Tabelle 2); bei 4 klx (kilolux) erzeugten die Pfl?nzchen normale Bl?tter und ein gut entwickeltes Wurzelsystem, w?hrend eine Beleuchtung von 2 klx nur ein schwach oder nicht entwickeltes Wurzelsystem und eine geringe Blattausdehnung bewirkte (Abb. 1). Agar hatte keinen Einfluss auf die Bewurzelung, aber es ver?nderte das Wurzelbild: auf flüssigen N?hrl?sungen kultivierte Meristemspitzen erzeugten ein gut entwickeltes Wurzelsystem und kr?ftigere Pflanzen als solche auf Agar-N?hrboden (Tabelle 3, Abb. 2). Das Vorhandensein von Gibberellins?ure (GA₃) war für die Bewurzelung sehr wichtig, obwohl einige Pfl?nzchen auch auf N?hrboden ohne GA₃ wuchsen (Tabelle 3). Die Bewurzelung von Pfl?nzchen auf flüssigen N?hrl?sungen ohne GA₃ war nicht von der Gr?sse der Meristemstücke anh?ngig (Tabelle 4); es bestand kein gesicherter Unterschied in der Bewurzelung zwischen den Meristemspitzen mit zwei Primordial-Bl?ttchen und jenen mit vier Bl?ttchen. Manchmal entwickelten sich in den flüssigen N?hrl?sungen Teratome (Abb. 3 und 4), die zusammen mit einer leichten Abw?rtsverschiebung des pH auftraten, w?hrend die normale Entwicklung stets von einer st?rkeren pH-Veranderung gegen das saure Milieu hin begleitet war.

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Résumé Les auteurs ont recherché les facteurs affectant le développement de pointes méristématiques de pomme de terre. Ils ont cultivé des sommets méristématiques de la variété italienneRicciona di Napoli sur un milieu de Murashige et Skoog modifié. Les essais se ont étendus sur une période de cinq mois, de septembre à janvier. Le spectre de lumière influence l'enracinement et la vigueur des plantules (tableau 1); les lampes fluorescentes avec un spectre de lumière approximativement semblable à la lumière du jour, mais enrichi en rayons rouges, ont donné les meilleurs résultats. L'intensité lumineuse constitue un facteur très important de la vigueur des plantules (tableau 2): 4 klx (kilolux) donnent des plantules montrant des feuilles normales et un système radiculaire bien développé, tandis qu'avec 2 klx, le système radiculaire est peu ou pas développé et le développement foliaire réduit (fig. 1). L'agar n'influence pas l'enracinement mais modifie l'aspect du système radiculaire: les sommets méristématiques développés sur substrats liquides produisent un système radiculaire bien développé et des plantes plus vigoureuses que celles qui poussent sur substrats agar (tableau 3, fig. 2). La présence d'acide giberellique (GA₃) s'est révélée importante pour l'enracinement, bien que quelques plantules se sont développées sur des substrats qui n'en contenaient pas (tableau 3). L'enracinement de plantules cultivées sur substrats liquides dépourvus d'acide giberellique ne dépend pas du volume des ‘explants’ (tableau 4): aucune différence significative ne s'est révélée dans l'enracinement entre les pointes méristématiques portant deux ébauches foliaires et des pointes méristématiques portant 4 ébauches foliaires. Quelquefois des formations tératologiques se sont développées dans les substrats liquides (fig. 3 et 4) et se sont manifestées en même temps qu'une faible augmentation du pH, tandis que le développement normal a toujours été accompagné d'une évolution du pH plus marquée vers les valeurs acides.

     

Field harvest damage affects potato tuber respiration and sugar content

Field and laboratory experiments demonstrate that damage to potato tubers increased tuber respiration, which declined with time. Measurement of tuber respiration with an infra-red gas analyzer can be a sensitive indicator of amount of tuber damage in actual field harvests. Damage of tubers had no effect on total sugar content but decreased sucrose content when measured ten days after harvest.     

Effect of temperature on the sugar content of potato callus tissue

The effects of temperature, incubation time, callus age, and growth regulator on the reducing and nonreducing sugars of Lemhi Russet callus grown on Murashige - Skoog medium with 3% sucrose were determined. Callus grown at 25°C for approximately 4 weeks (0 time) were held at 25°C or transferred to 15°C and 5°C for 4-week periods. Callus grown at 5°C for 4 weeks was transferred back to 25°C for a 4-week period to simulate reconditioning of potatoes. The reducing sugar content decreased rapidly with time at 25°C and 15°C when either 2,4-D or picloram was used as a growth regulator. At 5°C the reducing sugar content increased or decreased slightly, depending on the original reducing sugar content of the callus. The initial reducing sugar content at 25°C and the relative effect of 5°C incubation was dependent on the age of the callus tissue. Reducing sugars in 5°C callus were rapidly lost after reconditioning at 25°C. The nonreducing sugars exhibited similar overall changes as the reducing sugars, but the nonreducing sugar concentrations were much lower. Thus, potato callus cultures are similar to whole tubers insofar as they accumulate or maintain high reducing sugars at low temperatures and lose these sugars during reconditioning.     

An economic evaluation of consumer characteristics affecting fresh potato consumption

The purpose of this report was to relate several economic and social characteristics of consumers to level of fresh potato consumption. National cross-sectional data were used to identify consumption patterns using the least squares regression procedure. Relationships were estimated for white and nonwhite households The relationships for white households indicated that price of fresh potatoes, family income, number of meals eaten-at-home, family size, and expenditures for sweet potatoes were important determinants of weekly fresh potato consumption. Regional, urbanization and seasonal differences were also apparent for white households. Age and expenditures for processed white potatoes were less critical in determining consumption patterns The relationship for the nonwhite households was similar structurally to the white household relationship in many respects. Actually, age, expenditures for sweet potatoes and processed white potatoes and a couple of shift variables were the only ones which did not exhibit statistically significant coefficients. Seasonal and regional differences were noted.     

Respiration and sugar content of potato tubers as influenced by storage temperature

American Journal of Potato Research - Tubers of Russet Burbank, Kennebec, Targhee, Pioneer, Norchip and Aberdeen selection A68678-1 were stored at 95% relative humidity and at 1.7, 4.4, 5.8, 7.2 or...     

Management of insect pests in celery and potato crops by pneumatic removal

Over the course of 4 years, five sets of trials were run in celery and potato crops to evaluate the efficacy of a field-scale vacuum (FSV) unit for use in insect pest management. The unit was designed to dislodge insects by blowing air from lateral vents onto the plants while simultaneously vacuuming from above. Efficacy was evaluated by field observations, yellow sticky traps and hand vacuum sampling before and after the FSV. All insects evaluated were effectively removed by the vacuum unit; typically, population reductions of 50–75% were achieved with whiteflies, leafhoppers, and aphids. In some trials, reductions were achieved that lasted from week to week. Additionally, agromyzid leafminers were significantly reduced in number, but population reductions were temporary because of their strong flying ability.