Internal Heat Necrosis Research Articles

Performance of Chip Processing Potato Varieties in Northeastern Florida

Potato (Solanum tuberosum) is a high value crop in Florida. It consistently ranks in the top five valued vegetable crops produced in the state. The identification of new potato varieties that improve production efficiency is an imperative because of constantly evolving market and production demands. A chip potato variety evaluation experiment was conducted in northeast Florida in 2002 to compare the production characteristics of industry standards to advanced selections. The potato varieties evaluated in this experiment were bred specifically for processing by the potato chip industry. The experimental design was a four (site) by five (variety) factorial with four replications at each site. The sites were the University of Florida's research farm in Hastings, FL and three commercial farms in the surrounding area. Potato varieties were two seed sources of `Atlantic', as well as, `Snowden', B0564-8, and B0766-3. Marketable yield for each variety was 39.4, 33.4, 38.4, 33.6, and 33.6 t·ha-1 (351, 298, 343, 300, and 300 cwt/acre), respectively. Total yield of B0564-8 was statistically equivalent to an `Atlantic' standard at all four locations and similar to `Snowden' at three of four locations. Specific gravity of B0564-8 and B0766-3 was significantly lower than that of `Atlantic' from both sources but within acceptable range for chip potatoes. B0564-8 tubers had the highest overall appearance ratings and the most consistent size and shape. B0564-8 and B0766-3 tubers had a significantly lower percentage of hollow heart and internal heat necrosis than `Atlantic' tubers. This resulted in overall better chip ratings for the numbered entries compared to `Atlantic' tubers. A potential fit for B0564-8 and B0766-3 in northeastern Florida production may be as a late season chip variety when the potential for the development of internal heat necrosis increases.

Red-skinned, Fresh-market Potato Varieties for Northeastern Florida Production

Potato (Solanum tuberosum) is an important agricultural crop for Florida. From 1996 to 2000, the winter and spring potato crop was grown on an average of 15,782.7 ha (39,000 acres) and valued at $117 million. Variety evaluation and selection is an important tool to improve production efficiency and increase the competitiveness of Florida growers. A red-skinned potato variety evaluation was conducted in northeastern Florida in 2002. The experimental design was a 4 (site) × 5 (variety) factorial with four replications at each site. The four sites were the University of Florida's Plant Science Research and Extension Unit and three local commercial farms. Potato varieties in the trial were `Red LaSoda', `LaRouge', B0984-1, B1145-2, and B1758-3. Marketable tuber yields were 36.3, 35.6, 30.2, 20.3, and 21.4 t·ha-1 (324, 318, 269, 181, and 191 cwt/acre) respectively, with tuber yields of the two named varieties significantly higher than the numbered entries. Specific gravity ranged from 1.060 (`Red LaSoda') to 1.070 (B0984-1). There were no significant differences among entries for total cull weight or the incidence of hollow heart, brown rot, or corky ringspot. However, a higher percentage of B0984-1 tubers showed symptoms of internal heat necrosis than all other varieties. Potato varieties ranked from lowest to highest in overall appearance were `LaRouge', `Red LaSoda', B1758-3, B0984-1, and B1145-2. Higher appearance ratings in the numbered entries were attributed to darkerred skin color, rounder tuber shape, and shallower eyes compared to `Red LaSoda' and `LaRouge'. `Red LaSoda' and `LaRouge' will continue to be recommended as the standard redskinned potato varieties for Florida. However, B0984-1 and B1145-2 had desirable characteristics and should be planted in larger plantings to further evaluate quality and production characteristics.

Stability of Internal Heat Necrosis and Specific Gravity in Tetraploid × Diploid Potatoes

Stability of Internal Heat Necrosis and Specific Gravity in Tetraploid × Diploid Potatoes

Broad‐Sense Heritability and Stability of Internal Heat Necrosis and Specific Gravity in Tetraploid Potatoes

Internal heat necrosis (IHN), a severe physiological disorder of potato (Solanum tuberosum L.) tubers, is characterized by brown spots or blotches that first appear toward the apical end of the tuber parenchyma but in severe cases may involve most of the parenchyma tissue. The purposes of this study were to determine the amount of genetic variation for and the stability of IHN in tetraploid potato clones, and the relationships among IHN, specific gravity, and tuber size distribution. Nineteen potato clones (four cultivars and 15 breeding selections) were grown in Bridgeton, NJ and Painter, VA from 1991 to 1993 in a randomized complete block with four replications of 20 hills per plot. The crop was harvested 2 to 3 wk later than normal harvest time to provide for maximal exposure to heat stress. All tubers were harvested and graded by size. All tubers >64 mm in diameter were quartered longitudinally and rated by size for IHN Incidence and severity of IHN were recorded. Broad‐sense heritabilities and their 95% confidence intervals were: 0.83 (0.68, 0.93) for incidence of IHN in Size 3 (64–83 mm diameter) tubers; 0.88 (0.71, 0.94) for incidence in Size 4 (>83 mm diameter) tubers; 0.85 (0.72, 0.94) for severity of IHN in Size 3 tubers; 0.90 (0.78, 0.96) for severity of IHN in Size 4 tubers; 0.92 (0.85, 0.97) for specific gravity in Size 3 tubers; 0.77 (0.54, 0.91) for specific gravity in Size 4 tubers; and 0.86 (0.73, 0.94) for total yield. Several of the more IHN‐susceptible clones were unstable for IHN both before and after environmental heterogeneity was removed. The correlation between incidence and severity of IHN was very high. There was no correlation between IHN and total yield or specific gravity. The results of this study indicate that breeding high yielding, high specific gravity cultivars for resistance to IHN should be feasible.

Internal heat necrosis in the Midatlantic region — Influence of environment and cultural management

Internal heat necrosis in the Midatlantic region — Influence of environment and cultural management

A heat-sum model to determine yield and onset of internal heat necrosis for atlantic potato

The influence of temperature on tuber yield and development of internal heat necrosis (IHN) in Atlantic (Solanum tuberosum L.) was examined in field trials in two locations over three years (seven plantings). Under simulated commercial production, yield and development of IHN varied significantly between Virginia (VA) and New Jersey (NJ) in 1986, 1987, and 1988. Marketable yield ranged from 49.8 mt.ha−1 for the early planting in 1986 in New Jersey (NJ86E) to 17.9 for VA87. Tubers developing IHN to a level which potato chip processors would rate unacceptable (off-grade) varied with year and location. Significant correlations were found between the number of days to off-grade and the mean maximum temperature for 0–30 (r = −.83), 30–60 (r = −.86) and 60–90 DAP (r = −.81) as well as the mean minimum temperature for the same periods (r = −.91,, −.80 and −.91, respectively). The relationship between yield or IHN and temperature was examined using heat-sum models with a penalty for maximum daily temperature > 25C but with or without a penalty for minimum temperature > 21C. The multiple coefficients of determination for yield were similar using either variables generated from the heat-sum model with maximum and minimum temperature penalties or from the model with maximum temperature penalty only (R2 = 0.83 and R2 = 0.82). The prediction of the time from first symptom of necrosis to off-grade (interval) was improved by including variables generated by the heat-sum model that included both the minimum and maximum temperature penalty (R2 = 0.50 vs. R2 = 0.27), respectively. High minimum temperatures as reflected in the days to maximum heat-sum were found to significantly affect tuber yield and the expression and development of IHN.

Effect of year, location, and harvest on susceptibility of cultivars to internal heat necrosis in North Carolina

Internal heat necrosis (IHN) is a physiological disorder that affects potato quality. The influences of year, location, harvest date, and tuber size on the incidence of IHN were investigated toward developing an IHN screening technique. In 1989 and 1990, potato cultivars were grown at two North Carolina locations with normal season (90–105 days) and late (115–125 days) harvests at each location. At each harvest, yield data were taken, tubers were divided into three size classes (1= 48–64 mm, 2 = 65–83 mm, and 3 = > 83 mm), and 20 tubers were evaluated for amount and severity of IHN within each size class. More IHN was observed when tubers were sampled in size class 2 versus size class 1; there were not enough tubers in size class 3 to evaluate. Cultivars differed significantly in their susceptibility to IHN. Location did not influence the amount of IHN observed. Time of harvest also did not significantly affect incidence of IHN. The amount of IHN varied greatly depending on the year. Resistant and susceptible checks are strongly recommended to be included in future IHN field studies to monitor yearly variation in IHN severity.

Influence of calcium on internal heat necrosis of Atlantic potato

While Atlantic is the cultivar of choice of potato chip processors for the mid-Atlantic region, susceptibility to internal heat necrosis (IHN) greatly increases grower risk of economic loss from unsalable tubers. Yield, tuber calcium levels, and percentage of tubers with IHN of several cultivars from a common seed source were examined at two locations. The percentage of tubers with IHN were significantly higher for Atlantic while the tuber Ca concentration was lower than those of Superior. Both the percentage of tubers with IHN and tuber Ca concentration was higher in New Jersey than Virginia. Lower Ca levels were found in tubers with necrotic medullary tissue than in those without.

Relationship of Internal Heat Necrosis of Potato to Time and Temperature after Planting

The progression of internal heat necrosis (IHN) of `Atlantic' potato was studied in seven plantings in two locations (Virginia and New Jersey) over 3 years. The incidence (percentage of tubers with necrosis), severity (rating), and distribution (percentage of 1/8 pieces with necrosis per tuber) of IHN increased with successive harvests, but varied with year and location. Significant but weak linear correlation coefficients were found for the IHN variables of incidence, rating, and distribution with either time in days after planting (DAP), yield, or percentage of tubers >64 mm in diameter. Models were developed using stepwise regression to relate IHN variables with DAP, yield, percentage of large tubers, and various temperature and rainfall measurements. Time (DAP), penalty (DAP to first occurrence of three consecutive days of negative accumulated heat units), and rainfall (1 to 60 DAP) were significant variables in regression models for incidence and rating. While DAP and penalty were significant variables in the regression model for distribution, the variable rainfall was not included in the model. These findings indicate that the potential of IHN in `Atlantic' varies with the growing season, and is influenced by more than one environmental

Predictive Model for Onset and Development of Internal Heat Necrosis of `Atlantic' Potato

In `Atlantic' potato (Solanum tuberosum L.) the onset and development of internal heat necrosis (IHN) varied with planting date and location in 1989. Symptoms of IHN (first trace) took fewer days to appear in the later plantings in Virginia and New Jersey. However, the interval from first trace to offgrade was extended in the later plantings. Data from successive harvests in these two locations over the past 4 years were used to develop a two-stage model to predict first trace and offgrade by stepwise regression techniques. The predictive model for first trace included rainfall and variables calculated from a heat-sum model that reflected maximum and minimum air temperatures during tuber initiation and early enlargement. The addition of variables reflecting size distribution and rainfall events at first trace resulted in a strong predictive model for offgrade (R2 = 0.98, Mallow's criterion = 2.97). These models indicate that onset and development of IHN are influenced by environmental stress during more than one stage of growth. A delay in the development of offgrade tubers would be expected in years with a cool, wet spring, fewer tubers >64 mm in diameter at first trace, and more rain events during the 10 days immediately after first trace.