The relationship between tuber size and hollow heart in Norgold Russet potatoes

Hollow heart (HH) when found in potatoes is predominately in the largest tubers. Various tuber lots of cv Norgold Russets ranged from 3.4 to 55.9% HH by weight. In the lot with the least HH approximately 43% of the tubers over 8.89 cm in diameter were hollow compared to 0.2% of those between 3.81 and 5.07 cm. By first removing the very largest, followed by successively smaller tubers there was a continuous reduction in HH in all tuber lots. There were only small differences among the five years in the effect of sizing on HH, and these appeared to be associated with yield differences among years. Figures illustrate the specific effect of removing progressively smaller tubers on the amount of HH remaining.     

Effect of seed tuber and seed piece size on growth and incidence of hollow heart in Norgold Russet potatoes

Small seed pieces decreased yield and number of tubers. Both seed tuber and seed piece size affected the percentage of tubers with hollow heart. Hollow heart increased from 14 to 22% as the seed tuber size increased from 57 to 228 g and decreased from 27 to 19% as the seed piece size increased from 28 to 57 g. The least hollow heart (11%) occurred in tubers of plants grown from 57 g whole seed pieces and the most (26%) in tubers of plants grown from 228 g seed tubers cut into 28 g seed pieces. Hollow heart was positively correlated with the mean tuber size and negatively correlated with the number of mainstems per hill, total yield, and total number of tubers.     

Relationships between weather,plant spacing and the incidence of hollow heart in Norgold Russet potatoes

Partial regression analysis of ten years’ data showed the percent of hollow heart (HH) tubers by weight in Norgold Russet potatoes increased with an increase in number of days and rainfall between tuber initiation and plant killing, and decreased with an increase in plant population and degree day accumulation during the same period. Highly significant third order partial correlation coefficients for these variables with percent HH were: days between tuber initiation and plant killing 0.699, rainfall between tuber initiation and plant killing 0.320, plant population -0.530 and degree day accumulation between tuber initiation and plant killing -0.753. When these variables were used in a multiple linear regression model with% HH as the dependent variable the coefficient of determination (R²) was 0.72. The model was not significantly improved by including solar radiation, yield of tubers, number of tubers, or soil moisture at tuber initiation as other independent variables.     

Effect of planting date,spacing, and potassium on hollow heart in Norgold Russet potatoes

A 4 year study was conducted to determine the effect of planting date, spacing and potassium on the incidence of hollow heart in Norgold Russet. Hollow heart occurred in 3 of the 4 years; ranging from 5.7 to 45.9% in 1965, 8.2 to 24.1% in 1966 and 0.3 to 3.9% in 1968. depending on treatment. Based on the 4-year averages close spacing, early planting and potassium reduced hollow heart when weather conditions werefavorable for development. Of these treatments close spacing was the most effective control, and planting date was the least consistent in its effect of the factors sudied. In two of the years there was an association between increased numbers of tubers, increased yields and a lower percentage of hollow heart.     

Relationships between stem number,tuber set and yield of Russet Burbank potatoes

Five storage temperatures and three planting dates were used to obtain differences in seed performance. As seed storage temperature increased, average stem number per seed piece significantly increased. Stem number also increased with later planting dates. Germination tests, conducted under controlled temperatures, resulted in a curvilinear response with the least stems per seed piece at 10°C. a maximum stem number at 16°C and a slight decline in number at 21°C. The major effect of planting date was manifested through differences in germinating temperatures which resulted in increased stem number with later plantings. Yield of U.S. No. 1 tubers (5cm or 112 gm minimum) declined significantly as stem number increased. In the first planting, the correlation coefficient between stem number per seed piece and yield was r = ?0.95. Increased stem number and declining yield were attributed to advanced physiological age resulting from exposure to higher temperatures in storage and in the field. As stem number increased with planting date, tuber number also increased. The correlation coefficient between stem and tuber number for the first planting date was r = 0.92. The relationship declined significantly on the third planting date to r = 0.46. From these results it was concluded that economic yields are influenced by stem and tuber number which in turn can be manipulated by control of seed storage temperatures and planting dates.     

Some factors influencing shear force determinations of Norgold Russet and Russet Burbank potatoes

Norgold Russet did not increase in shear force readings with growth and development as did the raw product of Russet Burbank which showed a progressive increase in readings with growth during the latter half of the season. Seasonal differences were apparent with Russet Burbank, but not for Norgold Russet during the 3 years of this study. Higher shear force readings were recorded with an increase of specific gravity of Russet Burbank, but not for Norgold Russet. Low fertility level resulted in slightly higher shear force values possibly because of enhanced maturity. No major influence of moisture stress was evident. Higher shear force values resulted from longer periods of storage and with higher storage temperatures of Russet Burbank within the range of 34F to 45F.     

Relationship of specific gravity to sugar accumulation in stored Norgold and Russet Burbank potatoes

Studies were made on the influence of growing season and low fertility on reducing sugar accumulation in storage of the stem and bud portions of Russet Burbank and Norgold Russet potatoes separated into different specific gravity groups. The stem portion of Russet Burbank had a significantly different intercept and slope of regression line (between specific gravity and reducing sugar accumulation) than the bud portions of the same tubers indicating higher reducing sugar accumulation in the stem portion as well as differences in behavior as to amount accumulated at the different specific gravity levels. No significant difference in sugar content or behavior at the different specific gravity levels was obtained between stem and bud portions of Norgold Russet. Growing season did not cause significant differences in total sugar content or slope of the regression lines within the stem or bud portions of Russet Burbank. Low fertility level resulted in significantly higher sugar accumulation in the stem portion of Russet Burbank as compared to adequate fertility and there was also a trend toward less influence of specific gravity on sugar accumulation at the lower fertility level. Low specific gravity Russet Burbank potatoes tended to be more variable in sugar accumulation from year to year and also had wider differences in sugar accumulation between stem and bud portions than high specific gravity potatoes.     

Some factors influencing the pH of apical and basal portions of Russet Burbank and Norgold Russet potatoes

Studies were made of pH changes of apical and basal portions of Russet Burbank and Norgold Russet potatoes during growth and in storage. Russet Burbank had a higher pH of the apical portion during the later stages of growth as compared to the basal portion. No significant differences between the two portions were found during growth with Norgold Russet. After a period of moisture stress the pH of the basal portion of Russet Burbank dropped significantly. The basal portion of both varieties at higher specific gravities had higher pH after storage than the apical portion. A highly significant negative correlation was obtained after storage between reducing sugar levels of tubers of different specific gravities and pH levels in both varieties. There were no significant differences in pH among storage temperatures of 34, 38, 42 and 45 F. However, the pH level at 48 F storage was significantly higher than at the other temperatures. The pH level of tubers from seedlings and varieties were poorly correlated with their reducing sugar contents after storage. It appears that pH can be an indicator of potential chip color only within the confined limits of a specific lot.     

Relationships of seed size,spacing, stem numbers to yield of Russet Burbank potatoes

Studies were conducted in 1970 and 1971 to determine the relationships among seed size, spacing, stem numbers and yield of Russet Burbank potatoes. Cut seed sizes of 0.5, 1.0, 1.5, 2.0, 2 oz whole and a treatment consisting of 14% 0.5 oz seed, 62% 1 oz and 24% 1.5 oz seed were used in combination with seed spacings of 6, 9 and 12 inches. As seed became larger the average number of stems per seed piece increased. Percent stand and plant size rating also increased with larger seed. Total yields increased with an increase of seed size. The highest U.S. No. 1 yield was obtained with 2 oz whole seed spaced 6 inches apart with cut seed of the same size yielding slightly less. Within each spacing, the greater stem numbers per plot resulted in higher yields. However, when combinations of seed size and spacings were used to obtain a given stem number per plot, the higher stem numbers did not result in higher yields. A positive correlation coefficient of +0.982 was obtained between weight of seed piece/stem and total yield.     

Effect of antitranspirants on yield of Norgold Russet potatoes under greenhouse and field conditions

Antitranspirants (AT) were applied to greenhouse, field research plots and commercial plantings of Norgold Russet potato plants. In the greenhouse AT (Folicote and Vapor Gard) reduced water uptake by plants by 20–40%. In field trials at the Texas Agricultural Experiment Station, Halfway, similar concentrations increased yield of Norgold Russet potatoes by 21–45 cwts per acre (2352–5040 kg/ha). In a commercial trial on 20 acres of potatoes, 2% Folicote applied 5 and 3 weeks prior to vine kill increased total yield by 47 cwts per acre (5264 kg/ha) and increased yield of premium grade potatoes by 100%. Gross crop value at harvest was increased $500 per acre ($1125/ha). Significantly higher soil moisture levels existed in soils of treated plots between irrigations.     

Relationships between fry color and sugar concentration in stored Russet Burbank and Shepody potatoes

Relationships between french fry color and sugar composition of Russet Burbank and Shepody potatoes harvested at various chemical maturities (i.e., sucrose concentrations) and exposed to various temperature regimes during 8 to 9 months storage were examined. Combined data from 3 years of study showed fry color to be more closely associated with glucose during 8 C storage for Russet Burbank (r²=0.65) and Shepody (r²=0.62) than with fructose, total reducing sugars, sucrose, or total sugars. Glucose > 1.6 mg g^?1 in Russet Burbank and > 1.2 mg g^?1 in Shepody resulted in fries which were too dark to be eligible for maximum bonus paid by processors for good color. Russet Burbank harvested with sucrose > 3.1 mg g^?1 and Shepody harvested with sucrose > 1.6 mg g^?1 and preconditioned for 14 d at 15 C before storage at 8 C accumulated enough glucose in storage to result in fries which were darker than was acceptable for maximum bonus payment. Preconditioning at 15 C for 70 d was necessary to prevent Russet Burbank with sucrose of 3.9 mg g^?1 at harvest from accumulating unacceptably high glucose during storage. Glucose determined with enzymatic test strips was in close agreement with that by HPLC for both cultivars. The test strips could be used to estimate fry color of Russet Burbank.     

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.     

Influencing seed tuber yield of Ranger Russet and Shepody potatoes with gibberellic acid

Freshly-cut seed pieces of the potato cultivars Ranger Russet and Shepody were dipped in 0, 0.5, 1 or 2 mg/1 Gibberellic Acid (GA₃) prior to planting. GA₃ treatments increased stem and tuber numbers per hill of both cultivars and shifted tuber size profile toward the production of more seed-sized (up to 226 g) tubers and fewer large (greater than 340 g) tubers. The effect of GA₃ on reducing average tuber size was similar for the two cultivars. Total tuber yields were not affected. A 2 mg GA₃/1 seed piece dip decreased the yield of US#1 tubers in Ranger Russet primarily due to a significant increase in yield of tubers less than 226 g. Also, yields of culls were greater after a 1 mg GA₃/1 seed piece treatment, suggesting Ranger Russet is sensitive to this concentration of GA₃. One and 2 mg GA₃/1 seed piece dips to Shepody increased yields of tubers less than 113 g by 93% and reduced the yield of tubers greater than 340 g by 25% to 50%. GA₃ at 1 to 2 mg/1 may be useful in the production of seed potatoes with the cultivar Shepody which tends to produce many large tubers.     

Effect of whole seed tuber size and pre-plant storage conditions on yield and tuber size distribution of Russet Burbank

Field experiments were conducted in 1995, 1996, and 1997 at Agriculture and Agri-Food Canada’s Harrington Research Farm to assess the effect of whole seed tuber size and pre-plant seed storage conditions on processing yield (> 51 mm dia.) of potato (Solanum tuberosum L. cv Russet Burbank). Following commercial storage, seed tubers were stored at 4.4 C then subjected to one of three pre-plant treatments: (1) planted directly from storage, (2) held at 10 C for 3 wk before planting, or (3) green-sprouted for 3 wk before planting. Five sizes of whole seed were used (28, 42, 56, 70, and 84 g) with a variable size cut seed treatment added for comparison. Plots were harvested 138,134, and 131 days after planting in 1995, 1996, and 1997, respectively. Cut seed produced a higher yield of tubers > 51 mm diameter in comparison to all whole tuber seed sizes, with the exception of the 28 and 56 g sizes. In terms of total yield, the 28and 42-g whole seed tubers yielded significantly less than all other seed sizes examined. Warming or greensprouting seed tubers prior to planting did not increase tuber yield. The larger whole seed tuber sizes tended to result in greater numbers of stems and tubers per plant. To maximize marketable yield of Russet Burbank planted from whole seed tubers, it is recommended that the seed be between 28 and 42 g in size. Accepted for publication 25 May 2004.     

Effect of planting and harvest dates,location in the hill and tuber size on sugar content of Kennebec potatoes

A study was made with the Kennebec cultivar on the effect of planting and harvest times, location of tubers in the hill and tuber size on fructose, glucose and sucrose in tubers at harvest. The location of tubers in the hill did not affect fructose or glucose and had only a small effect on sucrose found in the tubers. Small tubers were higher in all three sugars than large tubers, and tubers from plants seeded later were higher in glucose and sucrose than tubers from plants seeded early. The early plantings at all harvests outyielded the late plantings. This together with the higher quality (lower sugars) support the recommendation that Kennebec potatoes to be used for processing should be planted early.     

Effects of several microbial seedpiece treatments on emergence,yield, tuber defects,tuber size distribution,and specific gravity of Katahdin and Russet Burbank potatoes in Maine

Several microbial seedpiece treatments were applied to Katahdin and Russet Burbank to determine their effects on emergence rates, yield, tuber defects, tuber size distribution, and specific gravity under Maine conditions. None of the seedpiece treatments affected total yield, final plant stand, or specific gravity, although several treatments caused slight delays in rate of plant emergence. Several of the seedpiece treatments increased yield of small tubers of Russet Burbank and shifted the yield of Katahdin slightly toward the larger grade size classes. None of the microbial seedpiece treatments was substantially different in performance from the other treatments; and none can be recommended as beneficial for potatoes in Maine.     

The effect of tuber size on the susceptibility of potatoes to metoxuron

Summary Field and pot experiments to determine whether the tuber size of volunteer potatoes affected their susceptibility to foliar applications of metoxuron are reported. The reduction in haulm weight of plants from small tubers (2–3 cm diameter) was greater than that of plants from large ones (4–5 cm diameter). This greater control was related to the lower vigour at spraying of the plants from the small tubers. It is suggested that these results could explain the variability in the level of control of volunteer potatoes achieved by metoxuron in carrot crops.     

X-ray images of hollow heart potatoes in water

Hollow heart is a defect which can cause serious problems in marketing potatoes. X-ray inspection is recognized as one of the most reliable non-destructive techniques for detecting hollow heart in white potatoes. Tests were conducted on potatoes having various degrees of severity of hollow heart and also on normal tubers. X-ray pictures were effective in exposing the hollow heart condition. The radiographic contrast between normal and defective tubers was enhanced by examining the tubers submerged under water. The x-ray image of sound potatoes was masked entirely while the hollow heart areas appeared as a bright spot under water. Results suggest that automatic sorting of potatoes for hollow heart may be simplified considerably if the tubers are x-rayed in a stream of water rather than in air.