Pacific Russet: An Early Maturing, Attractive Russet Cultivar with Excellent Culinary Quality

American Journal of Potato Research, Jul/Aug 2004 by Lynch, D R, Kawchuk, L M, Chen, Q, Wahab, J, Et al

YIELD AND QUALITY CHARACTERISTICS

The marketable tuber yield of Pacific Russet in the regional yield trials of the western Canadian Potato Breeding Program are included in Tables 1, 3a, and 3b. Similarly yield information from the U.S. North Central Trial, a multi-harvest date trial, and Ontario (Canada) trials are provided in Tables 5, 6, and 9, respectively. Marketable yield of Pacific Russet generally exceeds that of Russet Burbank when harvested for maincrop and Atlantic when harvested 80 or 90 days after planting. In 2000 in the U.S. North Central Trials, Pacific Russet exceeded the yield of Russet Norkotah at the Alberta, Michigan, and Minnesota sites and in 2001 at the Michigan and Ontario sites. In the multi-harvest date trial conducted at Vauxhall (Alberta, Canada) the yield of Pacific Russet exceeded that of Ranger Russet (Amisk) and Russet Burbank at 80, 90, and 110 days after planting. Ontario trials suggest that the yield of the new cultivar generally exceeds that of Russet Burbank and Goldrush. The specific gravity of Pacific Russet is moderate (Tables 1, 3a, 3b, and 7) and lower than that of Russet Burbank, Ranger Russet (Amisk), and Atlantic.

The tuber appearance of Pacific Russet is far superior to that of Russet Burbank and Atlantic (Tables 2, 4a, and 4b). Pacific Russet tubers show very low levels of internal and external defects (Tables 2, 4a, 4b, and 8).

In organoleptic tests conducted in western Canada (1996-1997) the texture of Pacific Russet was rated as mealy while Russet Burbank was rated as very mealy, and off-flavors were not; detected in the cooked product of Pacific Russet. In these tests the cultivar was also rated as resistant to after-cooking discoloration and sloughing. In 1999 the culinary quality of Pacific Russet was assessed after storage (Crop Diversification Centre - South, Brooks, Alberta, Canada) for a two- and four-month period at three temperatures (6, 8, and 10 C). At all temperatures and after both storage periods the texture was rated as mealy, the flesh color white, the flavor good (potato flavor), and the cooked product did not discolor.

DISEASE RESISTANCE

Pacific Russet is resistant to common scab and moderately resistant to Verticillium wilt and Fusarium wilt. The new cultivar is moderately susceptible to early blight and susceptible to Fusarium dry rot and late blight. Pacific Russet shows good visual foliar symptoms but only moderate tuber symptoms when infected with bacterial ring rot (Table 10). Disease reaction ratings for early blight, common scab, Verticillium wilt (inoculated), Fusarium wilt (inoculated), and bacterial ring rot (inoculated) were determined in replicated field plots using appropriate check cultivars. Fusarium dry rot (inoculated) and late blight (inoculated) reactions were determined under laboratory conditions. Rating categories were determined using Wards Minimum Variance Cluster procedure.

AGRONOMIC MANAGEMENT

Results of irrigated agronomy trials conducted in Alberta (Canada) suggest an optimum spacing of 30 cm within row (100 cm between rows) and that nitrogen rates as low as 90 kg/ha optimize marketable yield.