Partial collection of data on potato yield for experimental planning

The aim of this study was to estimate the number of blank experiments (BE) (i.e., a uniformity trial) required to estimate the optimum plot size for use in experiments involving potato crops. The study was based on data on the mass of potato tubers (Solanum tuberosum L.) from 3456 hills (i.e., 24 rows of 144 hills each) obtained from a BE. Using these data, BE of different sizes (i.e., 2 rows of 24, 36, 48 and 72 hills) were planned to estimate optimum plot size. For each BE, 11 plot sizes (X) were planned based on the sum of adjacent hills, and the mean, variance and coefficient of variation (CV) between plots of the same size were calculated. Regression models for CV were adjusted in terms of X to estimate the optimum plot size. For each BE size, a bootstrap resampling method was used to estimate the sufficient number of BE to enable precise estimates of optimum plot size, mean and other statistics. It was found that a sampling potato hill yield of 39% of subdivisions within an experimental area where a potato experiment is to be performed is sufficient to estimate optimum plot size for the experiment. Plots composed of one row of six hills are sufficient to estimate potato yield.     

Effect of pre-planting temperature and light treatments of seed tubers on potato yield and tuber size distribution

Summary From 1985 to 1987 field experiments were caried out to test the influence of different pre-planting storage treatments on yield and size distribution of potato crops. The storage treatments included 4, 8 and 12°C in the light and in the dark, for different periods before planting. Subjecting the seed tubers to light at low temperatures induced crops to produce a larger proportion of smaller sized tubers while storing seed tubers at higher temperatures in the dark led to an increase of tubers >55 mm. These observations were confirmed in five field experiments with two cultivars at two sites and in three growing seasons.     

Loss of yield in potato selections infested with potato leafhoppers

The loss of yield resulting from infestation with potato leafhoppers,Empoasca fabae (Harris), was measured in a group of potato selections (Solatium tuberosum subsp.tuberosum). For 6 years in which 300 different clones were tested, the average loss of yield was 39%. The correlation over clones between level of infestation and percent hopperburn equaled 0.56; between level of infestation and loss of yield 0.36; and between percent hopperburn and loss of yield 0.41. Each coefficient is significant at P=0.01. Significant differences were found in levels of infestation and in percent hopperburn among the selections, but even those selections with the most resistant foliage had greatly reduced yields when infested. No selections were found that consistently produced a normal yield when infested with leafhoppers. The low level of infestation on the more resistant clones, however, may make chemical control at lower rates more effective.     

Chemical control of potato early blight and its effect on potato yield

Potato early blight infection was reduced significantly by Daconil 2787, Difolatan and Manzate D. Rates of 0.50 1b/A to 1.5 1b/A were effective until inoculum loads increased as the season progressed then the higher rates were significantly more effective than the lower ones. Consistent yield increases in the range of 18 to 39% were demonstrated when early blight was controlled. Statistically significant yield increases were shown in seasons when severe Verticillium wilt or early killing frosts did not shorten the growing season and negate the beneficial effects of early blight control.     

Zone-subsoiling effects on potato yield and grade

Soil compaction and erosion are problems in many Pacific Northwestern potato fields. We wanted to determine if zone-subsoiling would reduce these problems and improve potato yields and or grade without adversely impacting other production practices. Studies were conducted in Southern Idaho at six locations over two years on different soils and with different irrigation methods to assess the effects of zone-subsoiling immediately after planting on tuber yield and grade. Reservoir-tillage comparisons were made at three locations where sprinkler water application rates were higher than soil infiltration rates. Russet Burbank was represented by eight location-years and Russet Norkotah by two. Zone-subsoiling consistently improved tuber grade or increased tuber size. The biggest improvement was under furrow irrigation. Zone-subsoiling also tended to increase total yield in eight of ten location-years. Reservoir-tillage improved yield and grade, but zone-subsoiling did not without reservoir-tillage when water application rates were high. At no location did zone-subsoiling significantly decrease tuber grade or yield. Zone-subsoiling had no appreciable effects on hill configuration or seed-piece dislocation. Surface cracking and “water piping” occurred under furrow irrigation but were not significant problems. Results were similar for both cultivars. Additional studies will be needed to successfully incorporate zone-subsoiling into commercial production practices     

Yield and yield components of meiotic tetraploids of potato

Summary In a field study simulating commercial practice, the performance of 4x meiotic tetraploids from 4x−2x crosses (Group Tuberosum×(Group Phureja×haploid Group Tuberosum), and their 4x and 2x parents, was studied for total yield, total number of tubers, number of marketable tubers and average tuber weight. Some of the families showed striking heterotic effects for these characters. 38 selected high yielding tetraploids from these families, when evaluated in the next season, gave 80% higher mean yield than the mean of the 4x parents. Publication No. 997, CPRI, Simla.     

Growth attributes of potato and their inter-relationship with yield

Summary In the mild and short winter of the Ganges plains, the yield contributing characters such as number of shoots/plant, plant height, leaflet size, tuber yield/plant and tuber number/plant were studied for fifty varieties of potato. From the simple, partial and genotypic and phenotypic correlation studies it was observed that leaflet size, number of tubers/plant and plant height were closely connected with the yield of potato tubers. A multiple regression equation was also prepared and it was found that the leaflet size had the maximum influence on yield followed by number of tubers/plant and plant height.     

Predicting yield and processing quality of potato breeding selections

The linear relationship between “site mean” and potato cultivar performance was used to develop predictive models for total yield, yield of US No 1 grade, per cent US No 1 grade, specific gravity and fried chip color. The best fitting linear expression for each of the traits was determined by linear regression for specific cultivars. Common limits for “site means” could then be substituted into the expressions for predictive purposes. Application of this method to large and small data sets demonstrated its use for interpreting preliminary yield trial information for the identification of superior breeding selections.     

Prediction of susceptibility of potato tubers to internal bruising by using a pendulum-mounted accelerometer

Summary Impact tests were conducted on two potato cultivars: Record, which is susceptible to blackspot, and King Edward, which is susceptible to internal crushing and shatter bruising. The type and size of each bruise resulting from each impact were recorded. A pendulum impact tester which had a piezo-electric accelerometer attached to the impacting head so that the acceleration-time curve of an impact could be recorded on a storage oscilloscope, was used. No difference was found between the dimensions of acceleration-time curves obtained from bruised and undamaged tubers. The occurrence of internal crushing and shatter bruising could be predicted with 77–87% accuracy from the characteristic shape of the acceleration-time curve produced by impacting susceptible tubers. The possibility of identifying the susceptibility of tubers to internal crushing and shatter bruising by using a pendulum impact tester with an accelerometer attached, is discussed.

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Zusammenfassung Der Ablauf der Verlangsamung eines auf eine Kartoffelknolle schlagenden Pendels wurde als Schnelltest zur Erfassung der Anf?lligkeit von Knollen gegen spezifische Typen von internen Besch?digungen verwendet. Ein piezoelektrischer Beschleunigungsmesser wurde in den Schlagkopf des Pendels derart eingebaut, dass die Beschleunigungs-Zeitkurve eines Schlages auf einem Lagerungs-Oscilloskop erfasst werden konnte. Für die Schlagtests wurden zwei Kartoffelsorten verwendet: Record, welche gegenüber Schwarzfleckigkeit anf?llig ist, und King Edward, welche gegenüber internen Quetschungen und Schlagverletzungen anf?llig ist. Die Schlagtests wurden an den Knollen zwei Tage nach der Ernte und nach 6-monatiger Lagerung durchgeführt. Typ und Gr?sse jeder Verletzung pro Schlag wurden erfasst. Schwarzfleckigkeit konnte von internen Quetschungen durch die eher blaugraue als braune Verf?rbung unterschieden werden, und bei der eher diffusen als scharfen Abgrenzung der Besch?digungen. Keine Unterschiede ergaben sich zwischen den Dimensionen der Beschleunigungszeit von besch?digten und unbesch?digten Knollen. Betrachtung der Kurven der Beschleunigungszeit von verschiedenen Knollen zeigte die Produktion zweier verschiedener Kurventypen. Die Kurven hatten entweder einfache oder mehrzackige Gipfel (Abb. 2). Von den Einfachgipfel-Schlagkurven konnten 83–87% auf Knollen bezogen werden, die unbesch?digt blieben. Von den Mehrgipfel-Schlagkurven liessen sich 77–78% auf Knollen mit internen Quetschungen oder Schlagverletzungen zurückführen (Tabellen 1 und 2). Kein Unterschied ergab sich zwischen der Form der Beschleunigungs-Zeit-Kurven von Knollen, die Schwarzfleckigkeit entwickelten, und von Knollen, die unbesch?digt blieben. Schwarzfleckigkeit k?nnte mit Sch?digung der Zellinhalte ohne gr?ssere Zellwand-Sch?digung Zusammenh?ngen (McIlroy, 1976). M?glicherweise war der Beschleunigungsmesser nicht empfindlich genug, Schaden nur für die Zellinhalte aufzuzeichnen, jedoch empfindlich genug zur Aufzeichnung von internen Quetschungen und Schlagverletzungen, die mit Zellwand-Sch?digung einhergehen (Hughes, 1981). Diese Begrenzung der Accelerometer-Technik wird als nicht schwerwiegend betrachtet, zumal die Ergebnisse dieser Untersuchung (Tab. 2) wie auch die Ergebnisse und Beobachtungen anderer Bearbeiter (Hughes, 1981; Specht, 1981) gezeigt haben, dass interne Quetschung und Schlagverletzung die vorherrschenden Formen interner Verletzungen zur Ernte oder kurz danach sind. Es wird vorgeschlagen, dass ein Pendelschlag-Testger?t mit einem angebauten Beschleunigungsmesser als Ausleseverfahren für interne Quetschungen und Schlagbesch?digungen in einem frühen Stadium eines Züchtungsprogrammes verwendet wird. Die Technik macht Sch?len oder Schneiden der Knollen nicht erforderlich, ferner wird die zeitliche Verz?gerung bis zur Verf?rbung, die mit der Entwicklung interner Besch?digungen einhergeht, vermieden.

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Résumé La mesure de la décélération d'un pendule percutant un tubercule de pomme de terre est utilisée comme test instantané d'estimation de la sensibilité à différents types d'endommagements internes. Un accéléromètre piézoélectrique est fixé au niveau de la tête d'impact du pendule afin de pouvoir enregistrer la courbe accélération — temps d'un choc sur un oscilloscope à mémoire. Deux variétés de pommes de terre sont utilisées pour les tests: la variété Record sensible au noircissement interne et la variété King Edward sensible à l'écrasement interne et l'éclatement. Les tests d'impacts sont rélisés sur des tubercules récoltés depuis 2 jours on stockés pendant 6 mois. Le type et la taille de l'endommagement sont notés pour chaque impact. Le noircissement interne est distingué de l'écrasement interne par sa coloration gris-bleue plut?t que brune et par des bords moins nets de la zone d'impact. Pour les tubercules blessés ou indemnes, la dimension des courbes accélération-temps est équivalente. L'examen des courbes accélération-temps obtenues à partir de tubercules différents montre qu'il existe deux formes distinctes de courbes: des courbes à pic simple ou à pics multiples. Parmi les courbes d'impact à pic simple, 83–87% correspondent à des tubercules restés indemnes. Parmi les courbes à pics multiples, 77–78% proviennent de tubercules atteints d'écrasement interne ou d'éclatement (tableau 1 et 2). La forme des courbes accélération-temps est semblable pour les tubercules présentant du noircissement interne ou restés indemnes. Le noircissement interne peut être associé à des endommagements intracellulaires sans endommagement important des parois cellulaires (McIlroy, 1976). Il est probable que l'accéléromètre ne soit pas suffisamment sensible pour enregistrer l'endommagement intracellulaire, mais suffisamment pour détecter l'écrasement interne et l'éclatement, qui eux sont associés à l'endommagement des parois cellulaires (Hughes, 1981). Cette restriction n'est pas considérée comme importante d'autantque les résultats de cette étude (tableau 2) ainsi que des travaux d'autres chercheurs (Hughes, 1981; Specht, 1981) ont montré que l'écrasement interne et l'éclatement sont les formes les plus communes d'endommagements internes à la récolte ou juste après récolte. Un système pendulaire couplé à un accéléromètre peut être utilisé comme test de dépistage de la sensibilité à l'écrasement interne et l'éclatement dans les premières étapes d'un programme de sélection. La technique évite le pelage ou le tranchage des tubercules ainsi que les délais nécessaires au développement de la coloration associée à l'endommagement interne.

     

The effect of potato virus X on the yield of the potato variety Hudson

The effect of a mild strain of PVX on the yield of the recently released potato variety Hudson was determined in split-plot experiments at three locations in New York. Two other varieties, Katahdin and Bake-King, were included for comparison. The yield data compared were total tuber yield, tuber yield > 2 1/4 in. and > 1 7/8 in. diameter and tuber number> 2 1/4 in. and > l 7/8 in. diameter. The effect of the mild strain was not great. Hudson appeared to be more tolerant to the mild strain of PVX than the other two varieties although the variety X virus interaction was very low.     

Effects of temperature pre-treatment of transplants from in vitro produced potato plantlets on transplant growth and yield in the field

Summary In vitro produced potato plantlets, cvs Gloria and Spunta were planted in soil and exposed to day/night temperatures of 18/12 or 26/20°C for 14 days. They were then transplanted into the field in two experiments to assess after-effects of temperature on the performance of short-cycle crops. Accumulated intercepted radiation (AIR) was calculated from ground cover and incoming radiation, and dry matter production and fresh tuber yield were frequently recorded. Pre-treatment at 26/20°C caused higher leaf area at the end of the transplant production phase and resulted in a higher AIR at the end of the field phase than pre-treatment at 18/12°C. Higher AIR, however, was not associated with significantly higher yield. Initially, the proportion of dry matter partitioned to tubers was lower after 26/20°C, but this effect did not persist. High temperature pre-treatment may improve the performance of plantlets, especially of very early potato cultivars.     

Physiological effects of calonyctin on development and yield of potato

Summary Foliar sprays of calonyctin, a natural plant growth regulator extracted from the leaves ofCalonyction aculeatum (L.) House, at a concentration 0.05 activity units, increased the tuber yield of six potato (Solanum tuberosum L.) cultivars by 7–19% (mean 15%) during 1993 and 1994. Physiological differences between calonyctin-treated and untreated potato plants were usually detected 30–40 days after spraying them with calonyctin. The chlorophyll content of treated potato leaves increased, and the chlorophyll a:b ratio decreased. By 40 days after treatment the root oxidizability and soluble protein contents of different parts of the plants also increased. Their subsequent decline as the plants aged was inhibited by calonyctin. It is concluded that calonyctin delayed the senescence of potato plants and increased tuber growth at later stages of development.     

The relationship betweenVerticillium albo-atrum inoculum density and potato yield

Population studies withVerticillium albo-atrum (microsclerotial form) have shown that a significant negative correlation exists between inoculum density in field soils determined before planting and yield of potatoes in some areas of Colorado but not in others. In Southern Weld and Morgan Counties where potatoes are planted early in sandy soils, reduced yield in Norgold Russet and Norchip cultivars occurred as inoculum densities increased. In Northern Weld County where potatoes are planted later in heavier soils, no such relationship was found. The significant relationship between inoculum density and reduced yield was associated with growing areas where conditions, particularly air temperature, appear to be favorable for verticillium wilt development when plants begin to mature. A minimum number ofVerticillium propagules was required to cause significant yield reductions in total, marketable and U.S. No. 1 grade categories. Below this minimum number, no significant yield reductions occurred. In Southern Weld and Morgan Counties, this minimum number was found to lie between 17.5 and 23 propagules per gram of soil. Controlled greenhouse studies showed that as air temperature decreased from 29.4 C (85 F) to 23.9 C (75 F) more inoculum was required to cause significant disease expression and to shorten plant life. This study has shown that in some areas soil inoculum assays prior to planting may provide a basis for selecting fields which are safe for planting potatoes to avoid severe losses from verticillium wilt. Furthermore, they may help in identifying fields where preventive control measures may be required for satisfactory potato production.     

Lime and phosphorus influence Kennebec potato yield and chemical composition

An experiment conducted in 1970 and 1971 with Kennebec potatoes on a Typic Cryothod near Willow Creek in Alaska compared the effects of seven P rates, with and without lime, on yields and chemical content of foliage and tubers. Each P increment increased plant vigor, foliage and tuber yields, P percentage in both foliage and tubers, K, Ca, and Sr concentration in the foliage and tubers, K, Ca, and Sr concentration in the foliage, and N, P, K, Ca, and Mg uptake by both foliage and tubers. The higher P rates depressed the A1 and Fe concentration in the foliage and the Ba in the tubers. Additions of high rates of P also tended to increase available P in the soil. Lime application decreased soil acidity, increased plant vigor, practically eliminated physiological leaf necrosis, and increased Ca and depressed Mn and Zn concentrations of both foliage and tubers. Lime further depressed the concentrations of A1, Ba, B, Cu, Fe, and Sr in the foliage and the Ba of the tubers. The uptake of N, P, K, Ca, Mg, and Na were also increased with lime applications because yields were greatly increased. Comparison of Ca/Mn and Mn/Fe ratios with those of another researcher (5) suggested a possible Mn toxicity. The concentrations of N and Cr in both foliage and tubers, and the amount of P, K, Na, A1, B, Cu, Fe, and Sr in the tubers were not influenced significantly by lime.     

Survey of potato production and possible yield constraints in Argentina

Summary The potato is the most important horticultural crop in Argentina. Its commercial cultivation started in 1872/73 and production greatly increased due to area and yield increases. This paper surveys potato production in Argentina. It describes and quantifies distribution of crop area and production and the agro-ecological conditions in each growing area. Yield constraints are identified and a yield gap analysis was performed using the LINTUL-POTATO simulation model. Possibilities for further yield improvement are discussed. The survey established that important yield improvements were achieved in the country during the last 20 years, mainly due to the use of high quality seed, new cultivars, improved fertilizers and irrigation techniques, and better control of pests and diseases. However, the actual yield, at least for the regions studied, is still well below the attainable and potential yields established with the LINTUL-POTATO model. Suggestions are made to improve further the potato yield in the different growing areas.     

Influence of irrigation and nitrogen management on potato yield and quality

The effects of irrigation, water and nitrogen management on yield and quality of the Russet Burbank cultivar are discussed relevant to developmental stages of growth. Recent research on the interactions of irrigation and nitrogen management on total and U.S. No. 1 yields and specific gravity are presented. Total and U.S. No. 1 yields decline with increasing soil moisture stress. Yield of U.S. No. 1 potatoes is particularly sensitive to short periods of irrigation deficit during tuber initiation. Total yield appears most sensitive to short periods of irrigation deficit during tuber bulking. Allocation of longer term irrigation deficits during years of limited water supply should be either a) avoided during mid-season tuber bulking, or b) uniformly distributed over the entire tuber bulking growth period. Yield increases with higher total available soil nitrogen under deficit irrigation, but the yield response diminishes as the amount of total seasonal water decreases. The influence of irrigation and nitrogen availability is also discussed for specific gravity and tuber maturity. Seasonal (split) nitrogen management is proposed as a method to improve yield, quality and nitrogen fertilizer use efficiency of indeterminant cultivars.