American Potato Journal

The Allagash Russet potato is an early to mid-season variety with oblong, attractive, uniformly-russeted tubers. Resistance of tubers to skinning and bruising during handling, and slow sugar build-up in cold storage are two advantages of this all-purpose potato. Tubers do not show the net necrosis associated with leafroll virus infection, and are moderately resistant to common scab.

Significant differences in tuber glycoalkaloid (TGA) content were found among parents and among family means in a two year study of 10 tetraploid crosses. TGA contents of the parents ranged from 3.6–36 mg/100 g, with an average content of 10 mg/100 g. Offspring variations within families were generally continuous, indicating polygenic inheritance. Heritability (1-year—1-replicate base) ranged from 86–89% in the broad sense and from 66–84% in the narrow sense. It was concluded that TGA content is highly heritable. The use of parents with high TGA contents in a breeding program is discussed.

Samples of Irish potato (Solanum tuberosum) from untreated and Imidan 50-WP—treated plots (four applications, 2.24 kg 50-WP/ha) were evaluated for flavor by a sensory panel of 16 judges. Although the sample means were statistically different (P = 0.05), no off-flavor was associated with the Imidan-treated baked potatoes.

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.

Red Pontiac tubers from 40 different midwestern sources were indexed to determine what strain or strains of virus X were present. A moderate strain of the virus was found to be commonly present. No distinct X-virus symptoms were observed in greenhouse-grown plants except for the periodic appearance of a faint leaf mottle, most easily detected on cloudy days. When grown outdoors, the leaves of Red Pontiac plants infected with the moderate strain had a slight upward, lateral roll and were slightly wrinkled. The infected leaves were not as dark green in color as virus-free leaves. The mean replicate weight of the X-free vines was 25.43 pounds compared to 17.41 for the infected plants; a highly significant difference of 31.54%. The mean replicate weight of the X-free tubers was 37.02 pounds compared to 28.93 for those infected with the virus. The difference of 8.09 pounds was highly significant and represented a 21.85% reduction in total yield.