S. B. Sterrett

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.Studies were completed in Virginia and New Jersey to evaluate the influence of Ca source, Ca rate and location within the hill as well as nitrogen rate on the onset and progression of IHN of Atlantic potato. Tuber yield was not significantly influenced by either Ca source (calcium carbonate (CaCO3) or calcium sulfate (CaSO4)) or Ca rate (0-1800 kg Ca/ha). Calcium rate had no influence on size distribution. As expected, a significantly greater percentage of large tubers were noted with delayed harvest. In a short growing season (<110 days) yield was not influenced by nitrogen rates ranging from 84 to 252 kg/ha. However, with delayed harvest, yield was increased and IHN slightly reduced with 168 or 252 kg N/ha when compared to 84 kg/ha. The influence of applied Ca on IHN varied between years, but the addition of Ca or N did not reduce IHN sufficiently to avoid out-of-grade because of internal defects. Location of applied Ca within the hill had no effect on yield, specific gravity, IHN, or tissue Ca concentrations. Slightly higher leaf Ca was found when using CaCO3 than CaSo4. The influence of Ca rate in 1987 and 1988 on leaf, periderm, or medullary Ca concentrations was not consistent. Nitrogen had no significant influence on tissue Ca levels.

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

Commercial potato chip processors in southern and eastern U.S. refer to necrosis of the parenchyma tissue internal to the vascular ring of potato tubers as internal heat necrosis (IHN). Symptoms of IHN include round-to-irregular, tan-to-reddish brown spots or blotches that appear first toward the apical end of the tuber. Necrotic tissu6appears at or near harvest and generally in the largest tubers (76.3 cm) first. Both the color intensity and the tuber area affected increase over time (Sterrett et al., 1991a). The presence of nonpathogenic necrotic parenchyma tissue in tubers has been reported using a variety of descriptive names in potato production areas worldwide. Necrotic tissue in potato tubers of various cultivars has been described as internal rust spot (Davies and Talbot, 1989); internal browning (Ellison and Jacob, 1952; Wolcott and Ellis, 1959); physiological internal necrosis (I.arson and Albert, 1945, 1949); internal brown fleck (Novak et al., 1986), or chocolate spot (Kamal and Marroush, 1971). I_arson and Albert (1945) reported economic loss in various varieties because of necrotic tuber tissue (physiological internal necrosis) in the commercial potato crop as early as 1937. In the 1950s, Wolcott and Ellis (1959) reported varietal differences in the development of necrotic tuber tissue (internal browning). Since the release of Atlantic (Webb et al., 1979), IHN has become a serious concern for growers in most areas when Atlantic is processed into chips directly from the field. The potential for high yield and high specific gravity of Atlantic is combined with desirable tuber characteristics for chip processing. Nevertheless, Atlantic is notably more susceptible to IHN than other varieties in the same trials (Henninger eta/., 1979; Sterrett and Henninger, 1991). From a survey of commercial growers in Virginia (VA) and North Carolina (NC), Sterrett and Wilson (1990) reported that the acreage left unharvested because tubers were out of USDA no. 1 grade as a result of IHN ranged from 3.2 to 11.2% over a three-year period (1986-1988). The necrotic symptoms found in Atlantic are similar to some symptoms reported for internal brown spot (IBS) or physiological internal necrosis and to some symptoms of IHN. Like IBS, necrosis in Atlantic occurs in tubers

Amey: A Multipurpose, Russet-Skinned Potato Cultivar for the Eastern United States

Amey is a late-maturing, russet-skinned, whitefleshed potato cultivar that yields more than Russet Burbank in most eastern United States potato production areas. Tubers of Amey are mostly oblong, occasionally long, with an evenly russetted skin. Tubers of Amey are smoother, more attractive, and have a much lower incidence of external defects than Russet Burbank. The specific gravity of Amey is equal to or greater than the specific gravity of Russet Burbank. French fries produced from Amey are lighter than or equal in color to those produced from Russet Burbank; however, tubers are frequently not long enough to satisfy the french fry industry. Baking and taste quality of Amey are excellent, and it has potential as a fresh market potato. Amey is resistant to race Rol of the golden nematode, powdery scab, and common scab. It is moderately susceptible to Verticillium wilt. It is susceptible to potato leafroll virus, late blight, and early blight.ResumenAmey es un cultivar de maduración tardía, piel marrón-rojiza y pulpa blanca, con rendimientos superiores a Russet Burbank en muchas áreas de producción de papa del este de los Estados Unidos. Los tubérculos de Amey son más oblongos y ocasionalmente más largos, con piel de coloración marrón rojiza. Asimismo, los tubérculos de Amey son más lisos, más atractivos y con mucho menor incidencia de defectos externos que los de Russet Burbank. La gravedad específica de Amey es igual o más grande que la Russet Burbank. Las papas fritas preparadas con Amey son más ligeras y de un color igual a his de dicha variedad, sin embargo, los tubérculos con frecuencia no son lo suficientemente largos para satisfacer los requerimientos de la industria de papas fritas. La calidad de horneado y palatabilidad de Amey es excelente y tiene potencial para el mercado de papas frescas. Amey es resistente a la raza Ro1 del nematodo dorado, roña y roña común. Es moderadamente susceptible a la marchitez por verticillium. Es susceptible al virus del enrollamiento de la papa, tizón tardío y tizón temprano.

Coastal Chip: A chipping potato variety resistant to heat stress

Coastal Chip is a medium-late maturing potato chipping variety suitable for production in locations along the east coast of the United States where heat stress reduces internal quality of tubers. It yields as well as the variety Atlantic but is not as susceptible to heat necrosis. The specific gravity of Coastal Chip averages approximately 0.010 less than Atlantic at locations subject to heat stress. In the seed producing areas of Maine it’s specific gravity averages approximately 0.005 less than that of Atlantic. Tubers are round, netted-skinned, and have moderately deep stem and bud ends. Chips from Coastal Chip are slightly lighter in color than those produced by Atlantic. In mid-Atlantic states where heat stress adversely affects chip color Coastal Chip processes into chips for a slightly longer period of time after harvest than does Atlantic. Glycoalkaloid content of Coastal Chip averaged 7.9 mg/100 g fresh tissue. Sunburned (green) tubers of Coastal Chip develop purple streaks that remain following processing. Hills must be properly covered to reduce losses. Coastal Chip is resistant to race A of the golden nematode (Globodera rostochiensis) and potato virus A. It is tolerant to Verticillium wilt, more susceptible to common scab and Rhizoctonia than Atlantic and susceptible to potato virus X.CompendioCoastal Chip es una variedad de papa de maduracion semitardía, de buena calidad para fritura a la inglesa, apropiada para ser producida en lugares de la costa oriental de los Estados Unidos donde el estrés por calor reduce la calidad interna de los tubérculos. Rinde tanto como la variedad Atlantic, pero no es susceptible a la necrosis por calor. La gravedad específica de Coastal Chip promedia aproximadamente 0,010 menos que la de Atlantic en los lugares expuestos al estrés por calor. En las zonas productoras de semilla en Maine su gravedad específica promedia aproximadamente 0,005 menos que la de Atlantic. Sus tubérculos son redondos, con piel reticulada y tienen extremos basales y apicales moderadamente deprimidos. Las papas fritas de Coastal Chip son de color ligeramente más claro que aquellas producidas con Atlantic. En los estados centrales del Atlántico donde el estrés por calor afecta severamente el color de las papas fritas a la inglesa, el procesamiento de Coastal Chip, después de la cosecha, toma un tiempo ligeramente mayor de aquel registrado para Atlantic. El contenido de glicoalcaloides de Coastal Chip promedia 7,9 mg/100 g de tejido fresco. El verdeo de los tubérculos de Coastal Chip expuestos al sol desarrolla estrías de color purpura que permanecen aún después del procesamiento. Los montículos de papa deben ser cubiertos adecuadamente para reducir las pérdidas. Coastal Chip es resistente a la raza A del nematodo dorado (Gbbodera rostochiensis) y al virus A de la papa. Es tolerante a la marchitez porVerticillium, más susceptible a la sarna común y aRhizoctonia que Atlantic y susceptible al virus X de la papa.

Coastal Russet: A mid-season Russet-skinned potato cultivar

Coastal Russet (tested as B9596-2) is a clone with mid-season maturity that produces russet skin tubers that are long and slightly flattened. Tuber yields in the eastern portions of the United States have been considerably greater than for BelRus. Tubers are well-shaped, have shallow eyes, and are attractive in appearance. Tuber appearance and size make this cultivar very well suited for the tablestock market. It is not suitable for processing. Coastal Russet is highly resistant to tuber net necrosis caused by late current season infection with leafroll and is tolerant to common scab.

PERFORMANCE EVALUATIONS OF VARIETIES AND SELECTIONS IN THE NORTHEASTERN REGION OF NORTH AMERICA

Marketable yield data were extracted from a regional trial system in the Northeastern United States and Canada. Three data bases were formulated containing data from selections (i.e. varieties and breeding lines) evaluated in trials in two consecutive years (1986–87, 1987–88 and 1988–89). Each data base was in the form of an incomplete two-way table as not all selections were tested at all trial locations. The analytic procedure was based on a linear model such that each selection was described by mean marketable yield and a sensitivity measure to environments, and each trial location was described by an environmental effect. An iteration process was used to estimate all parameters. A group of selections was evaluated in all three data bases. Mean marketable yields and sensitivity measures showed fairly good correspondence between data bases. The results provided useful information on selections with regard to their performance and adaptability in the region. A positive association was detected between mean marketable yield and the sensitivity measure, suggesting that a high yielding selection was more sensitive to environmental changes than was a low yielding one. Environmental effects were useful identifying high and low yielding areas. Correlation analyses between observed and fitted yields in individual trials showed that the linear model did not fit well for some trial locations. It is suggested that further research is needed for the investigation of data obtained from a network of trial systems.CompendioSe extrajo información de rendimiento comerciable de un sistema de ensayos regionales en el noroeste de los Estados Unidos y el Canadá. Se formulares tres bases de datos conteniendo información sobre selecciones (variedades y líneas de mejoramiento) evaluadas en ensayos realizados en tres años consecutivos (1986–87, 1987–88 y 1988–89). Cada base de datos se preparó en forma de una tabla incompleta de dos vías desde que no todas las selecciones fueron probadas en todas las localidades donde se ensayaron. El procedimiento analítico estuvo basado en un modelo lineal tal que cada selección fue descrita por la media del rendimiento comerciable y una medida de sensibilidad al ambiente, y cada lugar de ensayo fue descrita por un efecto del ambiente. Un proceso repetitivo fue utilizado para estimar todos los parámetros. Un grupo de selecciones fue evaluado en todas las tres bases de datos. La media de los rendimientos comerciables y las medidas de sensibilidad mostraron bastante bien la correspondencia entre las bases de datos. Los resultados proveyeron información util sobre las selecciones con respecte a su comportamiento y adaptabilidad en la región. Una asociación positiva fue detectada entre el rendimiento medio comerciable y la medida de la sensibilidad, sugiriendo que una selección de alto rendimiento era más sensible a los cambios ambientales que la de bajo rendimiento. Los efectos del ambiente fueron utiles para identificar zonas de alto y bajo rendimiento. El análisis de correlación entre los rendimientos observados y los deseables en ensayos individuales mostraron que el modelo lineal no se es conveniente para ciertos lugares de ensayo. Se sugiere que es necesario experimentar aún más para la investigación de la información obtenida de una red de sistemas de ensayos.