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.     

Potato composition: I. Tissue selection and its effects on solids content and amylose/amylopectin ratios

Solids content and amylose/amylopectin ratios were determined in different parts of tubers of White Rose, Red La Soda, Kennebec, Russet Burbank, Norchip and Lenape at harvest, after storage at 7 C for 2 and 4 mo, and after reconditioning at 20 C for 3 wk following each storage period. In all cultivars, solids content was greatest in stem-end, lower in bud-end and lowest in core tissue. The relationships for distribution of solids among the different parts of the tubers was not changed by storage treatments in any of the cultivars. Amylose/amylopectin ratios were similar in all parts of the tuber. Both the solids content and amylose/amylopectin ratio were changed by storage, but not uniformly in all cultivars.     

Textural quality of cooked potatoes: II. Relationship of steam cooking time to cellular strength of cultivars with similar and differing solids

The relationship of steam cooking time with cellular strength of cultivars Chieftain, Kennebec, Russet Burbank and White Rose was compared within and among solids concentrations. Nitrogen fertilization had no discernible effect on cell wall strength. Cell strength of Kennebec and Russet Burbank was similar regardless of solids concentration or cooking time. However, cell strength of Chieftain and White Rose differed with solids concentration and cooking time. Knowledge of cell strength and its characteristics with cooking time appear important for understanding the differences in textural quality that exists between cultivars.     

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.     

Correlations between quality parameters of potatoes during growth and long-term storage

The relationship between chip color, dry matter, sucrose, reducing sugars, ascorbic acid, protein, and storage temperature of commercially grown and stored Russet Burbank, Norchip, and Kennebec potatoes was investigated. Multiple correlation analysis of data, collected over a period of three years, demonstrated that while dry matter, reducing sugars, sucrose, and tuber weight were significant in determining chip color of freshly harvested potatoes, reducing sugars, tuber temperature, and sucrose were important in determining chip color of stored tubers. The relative importance of each parameter varied with the age of the tubers, year in which the potatoes were grown and stored, and cultivar. The multiple correlation coefficient among chip color, dry matter, sucrose, reducing sugars, and tuber weight was 0.901 for fresh Russet Burbank, 0.839 for fresh Norchip, 0.909 for fresh Kennebec, and 0.790 for the three cultivars combined. Similarly, the multiple correlation coefficient among chip color, reducing sugars, sucrose, and tuber temperature was 0.866 for stored Russet Burbank, 0.731 for stored Norchip, 0.914 for stored Kennebec and 0.790 for the combined stored material. Regression equations varied from cultivar to cultivar and from one season to another. This indicates that the quantitative relationship between the factors assayed was not sufficiently stable to serve as a general measure of prediction.     

Parenchyma cell growth in potato tubers I. Different tuber regions

Enlargement rates of starch-storage parenchyma cells during growth of Kennebec and Russet Burbank potato cultivars were determined for cortical, perimedullary, and pith tissuues of bud ends, midsections, and stem ends of tubers. Average volumetric size of parenchyma cells increased 7 to 18x during growth of Russet Burbank tubers, with the greatest increases occurring in cortical and perimedullary cells of bud ends and midsections, and the least in stem ends and pith tissues. In Kennebec tubers parenchyma cells in both stem end and midsection increased only 5 to 8 x, whereas increases in bud ends ranged from 8 to 20 times. Cell enlargement to tuber enlargement ratios appproached unity early in growth of Russet Burbank tubers. As tubers increased beyond the 45 g size, cell enlargement and tuber enlargement rates were essentially equal. Calculations of cells per unit tissue volume agreed with ratio determinations. The timing of such unity appeared to be delayed in Kennebec tubers, and was not quite as pronounced as in Russet Burbank tubers. This may have been due to differences in growth rates of individual tubers in response to cultural conditions. In general, cells of harvestmature Kennebec tubers were about 60% as large as similar cells of Russet Burbank tubers.     

Anatomy and compositional variations within potatoes. IV. Total solids distribution in different cultivars

Distribution of cortical, perimedullary, and pith tissues and total solids content were determined on both a fresh and a dry weight basis for six potato cultivars grown concurrently in three locations in California. At one location, tubers harvested 80 days from planting were 1.0 to 2.5% lower in total solids than tubers harvested at later dates. The high solids cortical tissues ranged from 39 to 51% of whole tubers on a dry basis, and the amount appeared to be related to tuber shape. White Rose and Red LaSoda showed greater difference in per cent total solids between cortical and perimedullary tissues than did Kennebec, Lenape,³ Norchip, and Russet Burbank. The high total solids of the cortical tissues is particularly significant to processing losses. Any method of peeling that removes one half the linear depth of the cortical tissues can result in a loss of 25% or more of total tuber solids, depending upon cultivar and tuber shape. Tuber development and distribution of total solids and other components were previously described for Red Pontiac, Russet Burbank, and White Rose tubers obtained from the retail market (6,9,10,11). It was particularly noted that the high-solids cortical tissues, although averaging only about 6mm in depth, comprised between 40 and 50% of both fresh and dry tuber weights (6,11). Because this sort of distribution of solids is especially significant to peeling loss, possible differences in solids among cultivars and at different harvest dates were investigated.     

Potato composition: III. Tissue selection and its effects on total nitrogen,free amino acid nitrogen and enzyme activity (polyphenolase,monophenolase, peroxidase and catalase)

Russet Burbank, Norchip, Kennebec, White Rose, Red La Soda and Lenape tubers were sampled at harvest, after storage for 2 and 4 mo at 7 C, and after 3 wk at 20 C following each storage treatment. Freeze-dried tissue from the bud-end, stem-end and core was analyzed for total, and free amino acid nitrogen, and for monophenolase, polyphenolase, peroxidase, and catalase activities. Significant differences among cultivars and among different parts of the tuber were found for all nitrogen fractions and all enzyme activities. Storage treatments significantly changed the total and free amino acid nitrogen contents and polyphenolase, peroxidase, and catalase activities. When compared for total nitrogen content and catalase activity, differences among different parts of the tuber which were statistically significant were similar in all cultivars. However, when compared for free amino acid content, and monophenolase, polyphenolase and peroxidase activities, differences among different parts of the tuber which were statistically significant were dependent upon which cultivar was examined. The differences among cultivars which were statistically significant for all nitrogen fractions and all enzyme activities, except peroxidase, were not significantly changed by storage treatment. The differences among different parts of the tuber which were statistically significant for quantity of both nitrogen fractions and for all enzyme activities were not significantly changed by storage.     

Tuber initiation and development in irrigated and non-irrigated potatoes

Tuber initiation and development are processes basic to potato production and are particularly critical in areas with short growing seasons. It is important to know how and to what extent management decisions affect these processes in order to maximize the yield of marketable tubers. A two-year field study, conducted in southcentral Alaska, examined top growth, tuber initiation, and tuber development in eight potato cultivars grown with and without irrigation. Plants of the cultivars Allagash Russet, Bake-King, Green Mountain, Kennebec, Lemhi Russet, Russet Burbank, Shepody, and Superior were harvested weekly throughout the growing season, and top dry weight, numbers of tubers, and individual tuber fresh weights were recorded. Top dry weight was reduced by moisture stress shortly after emergence in 1993, and about one month following emergence in 1994, when early-season soil moisture was greater. The weight of tubers was similarly affected within approximately 5 wk of emergence in 1993 and 6 weeks in 1994. Tuber weight at harvest was increased two-to three-fold by irrigation in all cultivars. The number of tubers each plant set was affected by irrigation in most, but not all, cultivars. Some varieties (Lemhi Russet in 1994, Allagash Russet both years) set more tubers than were maintained through the growing season. Tuber remnants found during sample collection indicated that tuber reabsorption had occurred. Irrigated Green Mountain had more than one tuber initiation period during the season, whereas other varieties such as Shepody maintained a relatively constant number of tubers following initial tuber set. Tuber size distribution at the end of the growing season showed that larger tubers were favored by irrigation.     

Changes in ascorbic acid content during growth and short-term storage of potato tubers (Solanum tuberosum L.)

Changes in ascorbic acid levels were followed in apical and basal portions of Russet Burbank and Kennebec tubers during growth and development. Influence of nitrogen fertilization during growth and short-term storage on ascorbic acid level of the tuber was also studied. Changes in ascorbic acid content during growth showed two distinct phases, the first phase being characterized by an increase in ascorbic acid content with growth and development of the tuber, followed by a second phase which showed a decrease in ascorbic acid content with increasing maturity. The shift from the first phase to the second phase occurred earlier for Kennebec than for Russet Burbank. Increased nitrogen fertilization resulted in a delay of this shift from the first to the second phase. The apical portion of the tuber consistently showed higher ascorbic acid content than the basal portion. Kennebec tubers were higher in vitamin C content than tubers of Russet Burbank cultivar. High nitrogen fertilization resulted in less ascorbic acid content during growth. Storage of tubers for four weeks at 5.5°C also resulted in a marked decrease in ascorbic acid content of tubers. Nitrogen fertilizer rate during growth had no influence on the decrease in ascorbic acid content of tubers in storage.     

Short-Term exposure to low temperature in the fall affects field performance of seed tubers

Field trials were conducted in Alberta and Ontario with Norchip, Norland, Russet Burbank, Sangre and Superior potato cultivars to determine response to short-term exposure of seed tubers to below freezing temperatures in the fall. Exposure of the dormant seed tubers to ?-1 C for up to 48 hours did not affect the yield or growth characteristics of the cultivars. However exposure of seed tubers to ?-5 C temperatures for 6 or 12 hours caused marked (P < 0.05) reductions in marketable yield, marketable tuber number, maturity and vine size. Exposure to ?-5 C for periods longer than 12 hours resulted in severe freezing damage and subsequent decay of most of the tubers.     

Utilization of potatoes for life support in space. V. Evaluation of cultivars in response to continuous light and high temperature

Twenty-four potato (Solanum tuberosum L.) cultivars from different regions of the world were evaluated in terms of their responses to continuous light (24 h photoperiod) and to high temperature (30 C) in two separate experiments under controlled environments. In each experiment, a first evaluation of the cultivars was made at day 35 after transplanting, at which time 12 cultivars exhibiting best growth and tuber initiation were selected. A final evaluation of the 12 cultivars was made after an additional 21 days of growth, at which time plant height, total dry weight, tuber dry weight, and tuber number were determined. In the continuous light evaluation, the 12 selected cultivars were Alaska 114, Atlantic, Bintje, Denali, Desiree, Haig, New York 81, Ottar, Rutt, Snogg, Snowchip, and Troll. In the high temperature evaluation, the 12 selected cultivars were Alpha, Atlantic, Bake King, Denali, Desiree, Haig, Kennebec, Norland, Russet Burbank, Rutt, Superior, and Troll. Among the cultivars selected under continuous irradiation, Desiree, Ottar, Haig, Rutt, Denali and Alaska showed the best potential for high productivity whereas New York 81 and Bintje showed the least production capability. Among the cultivars selected under high temperature, Rutt, Haig, Troll and Bake King had best performance whereas Atlantic, Alpha, Kennebec and Russet Burbank exhibited the least production potential. Thus, Haig and Rutt were the two cultivars that performed well under continuous irradiation and high temperature conditions, and could have maximum potential for adaptation to varying stress environments. These two cultivars may have the best potential for use in future space farming in which continuous light and/or high temperature conditions may exist. However, cultivar responses under combined conditions of continuous light and high temperature remains for further validation.     

Hill to hill variations in tuber yield of potatoes in Alberta

The hill to hill variation in tuber yield and mainstem number was studied on 18 potato farms. There were up to 14-fold differences in the tuber yield per hill among plants of Norland, Russet Burbank, Norchip, Carlton and Alaska Red. The mainstem number was more variable than tuber weight per hill in Norland, Russet Burbank and Alaska Red. However, the opposite was true in Norchip and Carlton. In nearly all comparisons, the number of tubers per hill was less variable than tuber weight and mainstem number per hill. The total variation in tuber weight found in about 50% of the samples could be explained by the variance of hills within rows. Even in samples where an added variance component due to differences among rows was present, relatively more variation occurred within than among rows. The correlation coefficients between the number of mainstems and tuber weight per hill were positive but significant (P&< 0.05) only in Norland and Norchip. The correlation coefficients between the number of mainstems and number of tubers per hill were also positive but slightly higher and significant (P<0.01) in all 5 cultivars. The coefficient of determination values indicated that variation in cut seed piece weight explained only about 10% of the total variation in tuber weight harvested per hill. At a spacing of 30 cm within the row, a major proportion of hill to hill variation in tuber yield had to be explained by factors other than the seed piece weight.     

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’.     

An evaluation of bromoethane for breaking tuber dormancy inSolanum tuberosum L.

Bromoethane was evaluated for its suitability to induce dormant tubers to sprout. Bromoethane immediately broke dormancy and caused multiple sprouting when applied to whole tubers as a vapor at 0.1 or 0.2 ml/L for 24 h at room temperature. Superficial and localized necrosis developed on the tubers if proper skin set had not occurred either in the field or after a curing period. In fall greenhouse trials, bromoethane treatment of whole tubers of the cultivars Red Pontiac, Russet Burbank, Bintje, Kennebec and Caribe induced them to sprout 40 to 70% earlier than untreated controls. Application of bromoethane significantly increased the mean rate of shoot elongation by 2.8 mm/day although there was no significant difference in its effect among the cultivars.     

Effect of planting date,nitrogen rate,and plant spacing on potatoes grown for processing in Prince Edward Island

Russet Burbank and Kennebec potatoes were evaluated over 5 years at 3 planting dates, 3 plant spacings, and 3 nitrogen rates. Delayed planting significantly reduced Russet Burbank yield, but did not effect Kennebec yield. Both varieties exhibited reduced specific gravity of tubers with delayed planting. Spacings between 38 and 56 cm for Russet Burbank and 20 and 38 cm for Kennebec had no significant effect on yields of “A” size tubers, but wider spacing reduced specific gravity of tubers. No yield advantage occurred with nitrogen application greater than 134 kg N/ha. Increased nitrogen application reduced specific gravity of tubers. Significant differences in the N, P, and K levels of leaves, petioles, and tubers were observed due to some treatments.     

Effect of daminozide on survival,growth and yield of micropropagated potatoes

The effect of daminozide [Butanedioic acid mono (2,2-dimethyl hydrazide)] on growth, field establishment and productivity of micropropagated Kennebec and Russet Burbank potato was studied. Addition of daminozide to the medium significantly reduced stem length ofin vitro propagated plantlets. Optimal dose was 0.6 mg active ingredient per plant. This dose did not significantly alter the number of nodes and leaf area. Three transplanting methods were examined: direct from tissue culture to the field without protection; the same but with a plastic covering for protection; and after 7 days acclimation in a greenhouse but without protection in the field. Stand establishment ranged from 83.3 to 100%. The second transplanting method had the highest percentage establishment for both cultivars. The application of daminozide improved survival for all transplants of Kennebec and the directly planted plantlets of Russet Burbank. Independent of the daminozide treatment, plants of both cultivars hardened in the greenhouse prior to transplanting produced the highest number and yield of tubers. For Russet Burbank, daminozide caused a delay in tuberization but did not affect tuber bulking and haulm growth.     

Cultivar response to Fusarium storage rot as affected by two methods of seed origin propagation; Clonal selection andin vitro culture

Progeny tubers from seed potatoes originating from either a traditional clonal selection method or the more modernin vitro tissue culture method of propagation were tested for storage rot response following inoculation of three tuber sites with twoFusarium species. Significant differences were found among disease responses for the twoFusarium species and for the four cultivars tested. Disease symptoms were less severe forF. solani var.coeruleum than forF. sambucinum. Fusarium sambucinum caused less disease in Superior than Kennebec, Russet Burbank and Sebago. Seed propagation method did not significantly affect disease response except for one case;in vitro culture of Kennebec had less disease due toF. sambucinum at the tuber side inoculation site than clonal selection. Kennebec and Superior inoculatedF. sambucinum had significant differences with respect to the number of years of field propagation for the tuber side inoculation site and for the tuber mean rot index. Significant differences in number of years of field propagation were also found for eye-ends of Superior tubers and stem ends of Russet Burbank tubers inoculated withF. solani var.coeruleum.     

Comparative levels of potato viruses S and Y infection of microplants and tuber-propagated plants in the field

The practice of transplanting microplants from tissue-culture to the field was compared to normal tuber propagation with respect to the transmission and translocation of potato virus S (PVS) and potato virus Y (PVY) to the daughter tubers of Red Pontiac, Shepody, Kennebec, and Russet Burbank cultivars in Prince Edward Island in 1984 and 1985. In general, the use of microplants to produce seed stocks appeared to increase the risk of infection with both viruses, although the results for tuber infection with PVY were only significant in one of the years.     

Utilization of potatoes for life support in space v. evaluation of cultivars in response to continuous light and high temperature

Twenty-four potato (Solanum tuberosum L.) cultivars from different regions of the world were evaluated in terms of their responses to continuous light (24 h photoperiod) and to high temperature (30 C) in two separate experiments under controlled environments. In each experiment, a first evaluation of the cultivars was made at day 35 after transplanting, at which time 12 cultivars exhibiting best growth and tuber initiation were selected. A final evaluation of the 12 cultivars was made after an additional 21 days of growth, at which time plant height, total dry weight, tuber dry weight, and tuber number were determined. In the continuous light evaluation, the 12 selected cultivars were Alaska 114, Atlantic, Bintje, Denali, Desiree, Haig, New York 81, Ottar, Rutt, Snogg, Snowchip, and Troll. In the high temperature evaluation, the 12 selected cultivars were Alpha, Atlantic, Bake King, Denali, Desiree, Haig, Kennebec, Norland, Russet Burbank, Rutt, Superior, and Troll. Among the cultivars selected under continuous irradiation, Desiree, Ottar, Haig, Rutt, Denali and Alaska showed the best potential for high productivity whereas New York 81 and Bintje showed the least production capability. Among the cultivars selected under high temperature, Rutt, Haig, Troll and Bake King had best performance whereas Atlantic, Alpha, Kennebec and Russet Burbank exhibited the least production potential. Thus, Haig and Rutt were the two cultivars that performed well under continuous irradiation and high temperature conditions, and could have maximum potential for adaptation to varying stress environments. These two cultivars may have the best potential for use in future space farming in which continuous light and/or high temperature conditions may exist. However, cultivar responses under combined conditions of continuous light and high temperature remains for further validation.