Relationships of hollow heart in Irish potatoes to carbohydrate reabsorption and growth rate of tubers

Tubers of Irish Cobbler that were hollow grew faster than non-hollow tubers on the same plant. However, tubers of varieties without hollow heart grew just as rapidly as tubers of the variety with hollow heart. Therefore tuber growth rate was related to hollow heart occurring within a variety but could not account for differences between varieties. When plant foliage was pruned the C-¹⁴ label from sucrose was translocated from the tuber to the top of the plant. Our studies suggest hollow heart can occur in small tubers under the following conditions: (i) moisture stress in the tubers resulting in conversion of starch to sugar, followed by a rapid influx of water into the tuber resulting in rapid enlargement of the perimedullary zone and a separation in the pith that later develops into hollow heart, and/or (ii), following injury to some cells in the tuber due to reabsorption of minerals and carbohydrates or depletion of food reserves followed by tuber enlargement. It seems probable however that hollow heart that is initiated in large tubers is only associated with excessively rapid tuber enlargement without the involvement of reabsorption or depletion of food reserves.     

Growth rate and carbohydrate metabolism of potato tubers exposed to high temperatures

Summary The effect of high tuber temperature (30 °C) on the growth rate and carbohydrate metabolism of tubers was studied with 3 cultivars differing in heat tolerance. Subjecting individual tubers to 30°C for 6 days caused cessation of tuber growth. During this period, non-treated tubers (20°C) on the same plant increased in volume. At 30°C, incorporation of¹⁴C-labelled assimilates into the ethanol-insoluble fraction (mainly starch) as well as the starch content was significantly reduced. In contrast, the incorporation of¹⁴C-labelled assimilates into the sugar fraction was not affected by high tuber temperature. At 30°C the activity of some of the enzymes involved in starch metabolism was depressed. Varietal differences in responses of tuber growth rate and carbohydrate metabolism to high tuber temperature were insignificant. From these preliminary results it is concluded that high soil temperatures may decrease starch content of potato tubers directly by inhibition of the conversion of sugars into starch.     

Effect of storage period, cultivar and two growing locations on the processing quality of french fried potatoes

The source of raw potato tubers and the tubers’ duration of storage have a significant effect on color and texture of french fries. Controlling these variations is crucial to ensuring a consistent, high-quality end product. Russet Burbank and Shepody potatoes grown at two sites in Manitoba, Canada were stored for 9 and 11 months in 1994, and for 1 and 3 months in 1995, to determine the effects of short-term storage period, cultivar, and two tuber-growing locations on fry color and texture. French fry texture was measured by a puncture test, and peak force and peak deformation used as indices of textural quality. Large peak forces and deformations were assumed to be indicative of improved textural quality. Hunterlab L (lightness) value was used to determine fry color, higher values being associated with improved color quality. Fries processed from 11-month-old tubers had improved color and textural quality compared to those processed from 9-month-old tubers. Fries processed after 3 months tuber storage were darker in color but firmer in texture than fries processed from tubers after 1 month of storage. Differences in texture and color between the two cultivars were more evident with prolonged storage; fries processed from Russet Burbank potatoes were superior in texture and lighter in color than fries made from Shepody potatoes. With respect to site, fries processed from potatoes grown at Portage had better texture but darker color than those processed from Carberry potatoes. It was postulated that the calcium content of the soils may be responsible for both these results.     

Modoc: A potato variety with bright red skin and early maturity for fresh market

Modoc is an early maturing, red-skinned, whitefleshed potato cultivar for fresh market use. The Agricultural Experiment Stations of Oregon, North Dakota, California, Idaho, and Washington jointly released Modoc in 2003. Modoc was derived from a 1989 cross of ND1196-2R and ND2225-1R performed at North Dakota State University. Modoc retains bright skin color in storage and is suited for marketing directly from the field or storage. It produces slightly lower total yield than Red LaSoda or Dark Red Norland, but higher marketable yield and more desirable tuber size and shape. Modoc tubers seldom exhibit growth cracks, secondary growth, hollow heart or other external or internal defects. Dry matter content of Modoc tubers is similar to Dark Red Norland and Red LaSoda (18.9% compared to 18.8% and 17.7%, respectively). Culinary quality of Modoc was rated equal to Dark Red Norland and Red LaSoda for boiling and microwaving preparation methods. Modoc tubers are similar to standard varieties in sugar, vitamin C, and glycoalkaloid (4.5 mg/100 g) concentration. Modoc foliage clearly expresses PVY symptoms and has not demonstrated high susceptibility to viral or fungal diseases during a decade of seed production and evaluation.     

Payette Russet: a Dual-Purpose Potato Cultivar with Cold-Sweetening Resistance,Low Acrylamide Formation,and Resistance to Late Blight and Potato Virus Y

Payette Russet is a full season, russet-skinned potato cultivar notable for its cold-sweetening resistance and associated low acrylamide formation, making it ideally suited for processing into French fries and other potato products. Low asparagine and reducing sugar concentrations in Payette Russet tubers contribute to an 81 % reduction in acrylamide content in French fries relative to cultivars Ranger Russet and Russet Burbank following eight months storage at 9 °C. In three years of evaluations in the Western Regional Potato Variety Trials, average yield of Payette Russet was intermediate between Ranger Russet and Russet Burbank, but Payette Russet had the highest U.S. No. 1 yield when averaged across all eight trial locations. Acceptably low tuber glucose concentrations (<0.10 % glucose FWB) were maintained in Payette Russet following up to nine months storage at temperatures as low as 5.6 °C with consistently acceptable French fry color scores obtained (USDA value ≤2.0). Reducing sugars are also maintained uniformly throughout Payette Russet tubers, resulting in a low incidence of sugar ends and reduced mottling in French fries relative to standard processing cultivars. Long tuber dormancy also benefits long-term storage for processing. With its russet skin, Payette Russet could also be used for fresh-pack, and its assemblage of disease resistances makes it especially suitable for organic production, or for use by growers and companies seeking greater sustainability in their production. Payette Russet is resistant to foliar and tuber late blight, common scab, and has extreme resistance to PVY conferred by the presence of the Rysto resistance gene. Payette Russet also has a moderate level of resistance to Verticillium wilt, early blight, and corky ringspot. It is susceptible to Fusarium dry rot (F. sambucinum), therefore production and storage management guidelines are provided to minimize tuber infection. Payette Russet displays a low incidence of second growth and growth cracks, especially relative to Russet Burbank, and is intermediate between Ranger Russet and Russet Burbank for incidence of hollow heart/brown center. Blackspot bruise expression for Payette Russet is similar to Russet Burbank and reduced relative to Ranger Russet. Payette Russet was more susceptible to shatter bruise, internal brown spot, and tuber weight loss in storage relative to the industry standard cultivars. Payette Russet was released in 2015 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington, and is a product of the Northwest (Tri-State) Potato Variety Development Program.     

Ivory Crisp: A potato variety with high tuber solids and cold chipping ability

Ivory Crisp was released in 2002 by the experiment stations of Idaho, Oregon, Washington, and North Dakota, and by the USDA/ARS. It resulted from a 1980 cross of ND292-1 and A77268-4. Ivory Crisp is suited for use in both the direct delivery and storage chipping markets. Ivory Crisp is a medium-maturing potato variety with round, white tubers and excellent chipping quality. It has medium to high yield potential, high tuber solids, resistance to most internal and external tuber defects, and the ability to chip from cold storage. In trials in Idaho, Oregon, and Washington, total and U.S. No. 1 tuber yield of Ivory Crisp was similar to Atlantic but lower than Chipeta. Yield of tubers in the size range 113–336 g for Ivory Crisp is higher than for either Atlantic or Chipeta. Ivory Crisp is resistant to growth cracks, secondary growth, hollow heart, and stem-end necrosis, but susceptible to shatter bruise. Tuber sugar content has consistently remained low following cold storage and near-acceptable chip color retained at 4.4 C. Ivory Crisp is susceptible or moderately susceptible to most common field diseases of potato. It is highly susceptible to common scab, powdery scab, and pink rot. Tubers of Ivory Crisp have dry matter content (22.4%) lower than those of Atlantic, but higher than those of Chipeta. Glycoalkaloid content of Ivory Crisp tubers is very low (4.3 mg 100 g^-1). An application for Plant Variety Protection has been filed for Ivory Crisp. Seed is available from potato seed growers in Idaho, North Dakota, and Canada. Small amounts of seed, for research purposes, can be obtained by contacting the corresponding author.     

Sugar-end in Russet Burbank potatoes

Tissue selected from the stem- and bud-end of reconditioned tubers having sugar-end disorder was compared by color after frying and chemical composition to tissue removed from the two ends of tubers without sugar-end disorder taken directly from cold storage at 45 F, and after reconditioning 3 weeks at 70 F. Chemical analyses of selected tissue suggested that the dark finish-fry color at the stem-end of sugar-end tubers following reconditioning at 70 F was due to the inability of the physiological systems within the tissue to convert reducing sugars to starch and/or to use these sugars in the respiratory process. Of the components analyzed, only a high reducing sugar content was associated with a dark finish-fry color. Neither sucrose nor free amino acid content was associated with the sugar-end disorder. Extending the reconditioning period at 70 F for sugar-end tubers did not lower the reducing sugar content or the darkening of the stem-end tissue on frying.     

Effects of transitory water stress on potato tuber stem-end reducing sugar and fry color

Potatoes grown for processing in irrigated regions of the Pacific North-west sometimes develop undesirably high concentrations of reducing sugars in tuber stem ends due to hot weather and water stress during tuber development. Such tubers usually produce french fries with dark stem ends or sugar ends. In order to better quantify the relationship between water stress and stem-end sugar levels for Russet Burbank, single episodes of transitory water stress were established by delaying irrigations until soil water potentials ranging from -32 to -107 kPa were reached during early tuber bulking. To determine when the increase in reducing sugars occurred, tubers were sampled before transitory stress, at maximum stress, after stress was relieved with sprinkler irrigation, and post harvest. Reducing sugar concentrations did not increase in tuber stem ends until two weeks or longer after the plant water stress was relieved. Increased reducing sugar concentrations were positively associated with decreased soil water potential (drier soil). Tubers were sliced and fried at harvest and six weeks post-harvest. Decreasing soil water potential (drier soil) was associated with progressively darker fry colors at harvest and post harvest. Significant darkening in the average stem-end fry color light reflectance of tubers at harvest as observed at -80 kPa in 1988 and -69 kPa in 1989. The effect of imposed water stress on tuber stem-end reducing sugar concentrations was most pronounced post harvest.     

IdaRose: A potato variety with bright red skin, excellent culinary quality, and long tuber dormancy

IdaRose is a late-maturing, potato variety with round, dark red tubers. It has high yield potential and exceptionally long tuber dormancy. IdaRose was released in 2000 by the USDA/ARS and the experiment stations of Idaho, Oregon, and Washington. It resulted from a 1982 cross of Sangre and TXA218-7. IdaRose is suited for use in both the early summer and storage fresh markets. Tuber yield of IdaRose is higher than that of Dark Red Norland and Sangre. It has yield potential similar to or slightly lower than Red LaSoda. Tubers of IdaRose have good internal and external quality. Culinary quality of boiled, baked, and micro-waved IdaRose tubers is excellent. It has moderate resistance to growth cracks, hollow heart, and other defect problems. IdaRose is susceptible or moderately susceptible to most common field diseases of potato. Tubers of IdaRose have dry matter content (19.2%) similar to other standard red varieties, and have a relatively high concentration of sugars and low concentration of glycoalkaloids (2.4 mg/100 g).     

氮素形态与马铃薯品质的关系

在田间条件下研究了不同形态氮素对马铃薯块茎硝酸盐含量、淀粉、蛋白质及还原糖含量的影响。结果表明,马铃薯块茎内硝酸盐含量从块茎形成期到成熟收获期是逐渐降低的。使用铵态氮肥并加硝化抑制剂双氰胺可以显著地抑制马铃薯块茎硝酸盐的积累;与硝酸盐含量变化相似,从块茎形成期到收获期蛋白质含量也逐渐降低,不同氮素形态处理对马铃薯块茎内蛋白质含量的影响无显著差异;铵态氮添加双氰胺处理可降低块茎还原糖含量。虽然马铃薯被认为是喜硝作物,但本研究表明,不同氮素形态处理不仅没有造成马铃薯产量的显著差异,而且块茎内淀粉含量也无显著差异。     

Effect of storage temperature on tuber composition,extrusion force,and Brabender viscosity

Kennebec potatoes were evaluated for the effect of storage temperature and time on tuber composition and on mealiness as measured by extrusion force of baked potato and Brabender viscosity of raw, lyophilized tissue. Potatoes from three specific gravity classes, 1.072, 1.082, and 1.090 (±0.001), were evaluated initially and after storage at 1.7°C for 2 and 3 mo., 7.2°C for 2 and 3 mo., 1.7°C for 2 mo. followed by 7.2°C for 1 mo., and 7.2°C for 2 mo. followed by 1.7°C for 1 mo. There were highly significant differences in mealiness associated with the storage treatments and with specific gravity. Mealiness decreased as temperature decreased. Mealiness estimates of tubers from the storage temperature reversal treatments were intermediate to those of the 7.2°C and 1.7°C treated tubers. Simple correlation analysis showed extrusion force and Brabender viscosity to be significantly and positively related to each other, to total starch and to swollen starch and significantly but inversely related to glucose and to the sum of glucose plus sucrose. Specific gravity and total solids were significantly but less highly positively correlated with both physical measurements. Multiple correlation-regression analysis showed only total starch to be significantly related to mealiness independent of the other compositional variables.     

Influence of low fertility and vine killing on sugar development in apical and basal portions of Russet Burbank potatoes

Russet Burbank tubers from plants which died prematurely (low fertility plots) accumulated significantly greater amounts of reducing sugars in storage than tubers from plants which were adequately fertilized. Also, a significantly greater difference in relative amounts of reducing sugars between the apical and basal portions was obtained from tubers of the low fertilizer regime. The basal portion had a three times greater amount of sugars than the apical portion. This is of particular interest to processors of French fries who try to obtain uniformity of color in processed fries. The difference in total reducing sugar accumulation in storage between tubers of high and low fertilizer regimes was greater at the lower storage temperatures. Tubers allowed to mature in the ground (second harvest date) accumulated less sugars in storage than tubers dug shortly after vine kill.     

Effect of seed piece population on the yield and processing quality of Russet Burbank potatoes

The effect of seed piece population on tuber yield, size distribution and processing quality of Russet Burbank potatoes grown under nonirrigated conditions in southern Manitoba from 1983 to 1987 was determined. Seed pieces were planted at 21.7, 26.3, 33.3 and 45.5 thousand seed pieces per hectare, and plant emergence generally exceeded 90% of the seed piece population. Marketable tuber (greater than 5 cm in diameter) yields were not affected by seed piece population. As population increased, however, the number of harvested tubers increased and average tuber size decreased, which resulted in a decreased yield of premium tubers (greater than 284 g) and an increased yield of small tubers (less than 5.0 cm in diameter). Specific gravity, the incidence of hollow heart in maingrade (5 cm in diameter to 284 g in weight) and premium tubers, and fry color were not significantly affected by seed piece population. In the one trial tested, sucrose content decreased as population increased, however, this was not reflected in improved fry color after storage.     

Relationships between tuber size and time of harvest to hollow heart initiation in Dryland Norgold Russet potatoes

In four years of field trials approximately75% of hollow heart was initiated in tubers between 5.1 and 7.6 cm in diameter. Only rarely was hollow heart initiated in tubers less than 3.8 cm. The frequency of hollow heart was approximately nine times greater in medium sized tubers (6.4 to 7.6 cm) and 34 times greater in large tubers (over 7.6 cm) than in small tubers (5.1 to 6.4 cm). The number of tubers with hollow heart increased linearly through the last five weeks of the growing season. Hollow heart during the four years ranged from 4200 to 31900 tubers/ha or 2.9 to 13.0% of all tubers over 2.5 cm. There were consistent increases in tuber growth between harvests in each season, inferring an absence of severe plant stress and supporting the hypothesis that hollow heart was due to tissue tension associated with tuber enlargement.     

Elkton: A New Potato Variety with Resistance to Internal Heat Necrosis and Hollow Heart and Suitable for Chipping Directly from the Field in the Southern United States

Elkton is a medium to medium-late maturing potato variety with tan netted-skin, round-oval tubers, and white-flesh. Average marketable yields ranged from 76 % to 113 % of Atlantic and average specific gravities ranged from ?0.002 to ?0.006 less than Atlantic depending on location. Chip color processed directly from the field in southern locations or from storage in the northern locations is equivalent to Atlantic. Elkton is resistant to internal heat necrosis and hollow heart. Color and texture ratings of Elkton following baking, boiling and microwaving have been similar to Atlantic. Elkton is moderately resistant to early blight and Verticillium wilt; moderately susceptible to foliar late blight and susceptible to tuber late blight; moderately susceptible to powdery scab; and, susceptible to potato virus Y and potato virus S. Its reaction to common scab has been inconsistent. Plant Variety Protection has been requested for Elkton.     

Carbohydrate metabolism during tuber initiation in potato: A transient surge in invertase activity marks the stolon to tuber transition

Summary The relationship between carbohydrate metabolism and tuber initiation in potato was determined by monitoring changes in the amount of starch and sugars along with the activities of sugar metabolizing enzymes upon transfer of plants to tuber-inducing conditions (TI; short days, cold nights) from non-inducing conditions (NTI: long days, warm nights). Switch to TI conditions caused an immediate slow-down in plant growth and triggered swelling of stolon tips, which went on to develop into tubers. Leaves of plants moved to TI conditions accumulated less starch and sugar while their stolon tips showed a sudden upsurge in starch content and a sharp decline in sugars even before any tip swelling was detectable. These changes were paralleled by a transient surge in the activity of cell wall invertase (74%) and soluble invertase (30%) in stolon tips of plants transferred to TI conditions in two unrelated cultivars under different experimental conditions. As the surge in invertase activity faded, it was replaced by a substantial increase in sucrose synthase activity as the tuber enlargement proceeded. The transient increase in invertase activity just prior to tuber initiation appears to mark a turning point in the transition of stolon tip to tuber.     

Reducing chilling injury of potatoes by intermittent warming

Potato tubers held continuously 19 weeks at 32 F developed chillinginjury symptoms early during storage and the symptoms worsened with time in storage. Early symptoms included browning and surface mold on skinned areas. By 11 weeks mahogany browning, blackheart, and hollow heart, bluish skin discoloration and sinking of intact skin were visible in daylight. And under ultraviolet light, yellow fluorescence was visible in halos, washes, or spots around or near internal tuber tissues discolored by other chilling-injury symptoms. Some damage at 32 F became visible after subsequent holding of tubers for 1 week at 60 F. Tubers accumulated high amounts of reducing and total sugar at 32 F and respiration, measured at 60 F as CO₂ evolved, was progressively stimulated by time at 32 F. Sugar build-up, respiration-rate increase, and chilling injury seemed to show no cause-and-effect relationship but appeared as separate phenomena each caused by the stress of holding tubers at too low a temperature. Moving potatoes to 60 F for 1 week after every 3rd week to interrupt storage at 32 practically eliminated all forms of chilling injury except skin browning and surface mold which were greatly reduced. Sugar content and respiration rates in tubers intermittently held at low and high temperatures were higher after periods in low temperature and lower after periods at 60 F, and in general were maintained at levels much lower than in potatoes held continuously at 32, 36, or 40 F. In all treatments sugar content was higher than desirable for chipping type potatoes. Holding potatoes at 60 F for 1 to 4 weeks before placing them at 32 F reduced skin browning and surface mold but had no effect on other forms of chilling injury, sugar accumulation, or respiration rates in tubers as measured after 15 to 19 weeks continuously at 32 F. Practically no chilling-injury symptom except for very little mold growth and browning of skinned areas developed in tubers held in 36 or 40 F.     

The response of potatoes to a single transient heat or drought stress imposed at different stages of tuber growth

Summary The effects of a single treatment of heat or drought stress imposed at different stages of tuber growth, were investigated in two potato cultivars, Désirée and Cara. Both stresses impaired dry matter accumulation in tubers, and tuber yields. Stress imposed at early stages of tuber growth, when tubers were less than 20 mm in diameter, had little effect on dry matter accumulation, whereas stress imposed later resulted ingnificant losses of dry matter in tubers. Stress imposed during later tuber growth increased the percentage of tubers sprouting in the soil. Tuber malformation was less affected. The adverse effects of heat on tuber yield and quality seemed to be greater than those of drought. Drought increased the content of total soluble solids (TSS) and lowered the osmotic potential in the tuber tissue of both cultivars. These effects were detectable even 55 days after stress relief. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel No 984-E, 1984 Series. This investigation was sponsored by a grant from the Ministry of Foreign Affairs, Technical Assistance Department, Netherlands.     

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.     

Starch to sugar interconversion inSolanum tuberosum L. I. Influence of inorganic ions

No relationship could be found between calcium, magnesium, potassium, total phosphorous contents, and reducing sugar accumulation in apical and basal portions of Russet Burbank tubers. However, a highly significant positive correlation was found between inorganic phosphorous content of tubers and reducing sugar accumulation. Inorganic phosphorous and sugar levels were highest in the basal portion of moisture stressed and low temperature stored tubers, suggesting a relationship between inorganic phosphorous and enzymatic activity in the interconversion of starch to sugars in potatoes. Tubers stored at 5.5 C and 15.5 C had higher contents of calcium and magnesium in the basal portion and significantly higher potassium content in the apical portion. Storage temperatures or moisture stress during growth appeared to have no significant influence on calcium, magnesium, potassium or total phosphorus contents of the tubers.