Oakes Irrigation Research Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Phone: (701) 742-2744, FAX: (701) 742-2700,

E-mail: Blaine.Schatz@ndsu.edu

Processing Potato Trial Oakes, North Dakota 2014

Asunta (Susie) Thompson

Yield and evaluation trials were grown at eight locations in North Dakota and Minnesota in 2014, five irrigated (Larimore, Oakes, Inkster, Williston, and Park Rapids) and three non-irrigated (Hoople, Crystal and Grand Forks) locations. This summary reports the results from the Oakes processing trial. Twenty-two advancing dual-purpose russet selections and commercially acceptable cultivars were included in the trial planted on May15. The field plot design was a randomized complete block, with four replicates; cultural practices typical of the growing area were used during the growing season, including sprinkler irrigation. Rows were 36 inches apart, and the within-row spacing was 12 inches. The plot was flailed on September 18 and harvested on September 19. Days to vine kill were 126 and to 127 days to harvest.

Agronomic and quality evaluations, yield and grade, and French fry quality are summarized Tables 1 (agronomic information), 2 (yield and grade information), and 3 (fry quality attributes), respectively. Percentage stand ranged from 81%, for ND071302B-5Russ, to 100% for several clones including Russet Burbank. Vine size ranged from 1.0 (very small) for ND8068-5Russ and ND071302B-5Russ) to 4.8 (large) for Dakota Trailblazer. Similarly, vine maturity ranged from 1.0 (very early) for ND8068-5Russ, ND071302B-5Russ, and Russet Norkotah, to 4.0 (medium late) for Dakota Trailblazer. The NDSU potato breeding program attempts to focus on high yielding, earlier maturing clones because of our often short growing season. Stems per plant are indicative of seed quality (physiological age), tuber eye number, and length of dormancy (genetic). Mean stem numbers per plant ranged from 1.2 to 2.8, with a mean of 2.1. Seed of ND8068-5Russ had been physiologically aged, and Teton Russet may also have been, based on stem number data. Tuber number per plant seemed low for all clones in 2014 from the Oakes site, with the exception of Umatilla Russet. Tuber number per plant ranged from 4.5 for ND071127-1Russ to 9.3 for Umatilla Russet. Umatilla Russet was small and somewhat spindly in all of our trials in 2014. Mean specific gravity was 1.0948, with a range of 1.0762 to 1.1140, for Teton Russet and Dakota Trailblazer, respectively. Specific gravity levels for many selections and cultivars were very high and out of processor specifications for this quality attribute. Percentage hollow heart and brown center ranged from 0 to 29, with a mean of 10. Several entries had high percentages, including clones that typically do not exhibit this physiological disorder. Some large rains and/or irrigation management may have contributed.

Total yield ranged from 270 cwt/acre for ND8068-5Russ, to 559 cwt/acre for Russet Burbank (Table 2). The mean was 442 cwt/acre. Percentage US No. 1 yield varied from 65 to 94. ND8068-5Russ, the very early dual-purpose russet, had 20% undersized tubers; others with many tubers 0-4 ounces included Umatilla Russet. The majority of entries had percentage yield of 6-12 ounce tubers in the 40-60% range. ND071127-1Russ had a propensity of over-sized tubers, and was the clone with low tuber numbers per plant. Manipulation of stem numbers via precutting or other means to increase stem and subsequently tuber numbers, and/or tighter within-row spacing would be appropriate management strategies to minimize tubers over 12 ounces for this selection and several others. ND092358ABC-6Russ, Teton Russet, Shepody and Russet Burbank had high percentages of culls. ND092358ABC-6Russ had shape issues including flat and points as reasons for culling tubers. Shepody and Russet Burbank had high numbers of jelly end tubers, curved tubers, and in the case of Russet Burbank many tubers were spindly shaped (too long for diameter). Teton Russet tubers had many large growth cracks.

All trial entries were evaluated for blackspot and shatter bruise potential. Blackspot bruise potential is assessed using the abrasive peel method of Pavek and Corsini. On a scale of 1 (none) to 5 (severe), clones ranged from 2.5 for Dakota Trailblazer to 4.4 for Ranger Russet and ND8068-5Russ (Table 1). ND8068-5Russ was possibly over mature, since it had been dead for more than a month. Shatter bruise potential is assessed using a bruising chamber with digger chain link baffles, and rated on a scale of 1 (none) to 5 (many and severe). The mean across trial entries was 1.9, with a range of 1.4 to 2.5 (Table 3). Our research is designed to identify processing (both chip and frozen) germplasm that will reliably and consistently process from long-term cold (38° F and/or 42° F, 3.3° C and/or 5.5° C, respectively) storage. A field (zero time) sample was collected during grading for immediate French fry processing, and after eight weeks storage from 45° F (7.2° C) for fry color, stem end fry color, sugar ends, and other defects. Several advancing selections and industry standards had outstanding French fry color when fried at harvest and after storage at 45° F for 8 weeks. All clones had acceptable French fry color and had leachable sugar ends with the exception of Teton Russet, Russet Norkotah, Russet Burbank and Shepody. Many selections demonstrate sugar end resistance. Our program assesses a sugar end as any color deviation from the main fry. This is more stringent than the processing industry that requires a score of a 3 or 4 on the color chart to be called a sugar end. Clones with stem end colors 2 or less can generally be managed during processing/manufacturing. Following 8 weeks of storage at 45° F, Russet Norkotah (used as a poor processing control) produced the darkest French fry colors. Russet Burbank and Teton Russet exhibited classic sugar ends from storage. French fry/frozen processing selections will also evaluated from 45° F storage in June 2015.

The most promising advancing dual-purpose (frozen processing and tablestock) russet selection is ND8068-5Russ, despite its performance in this trial. ND8068-5Russ has early maturity, seven to ten days earlier than Russet Norkotah. Unlike Russet Norkotah, it processes from the field and 45° F storage. Dakota Russet and Dakota Trailblazer continue to be top performers, although yield potential was reduced for Dakota Russet and Dakota Trailblazer had high levels of hollow heart/brown center. The trial was managed for Russet Norkotah and both of these clones require less nitrogen fertilizer to maximize yield and quality. We are in the early stages of developing a cultivar specific management profile for Dakota Russet. Several selections including ND102677B-1Russ and ND102707-2Russ show great potential and have excellent processing quality. They will be increased and further evaluated.

The potato breeding program is grateful for the opportunity to conduct cooperative and interdisciplinary research with members of the NDSU potato improvement team, the USDA-ARS programs in Fargo and East Grand Forks, the North Central research group and others across the globe. A sincere thank you, to our many grower, industry, and research cooperators in North Dakota, Minnesota, and beyond. I wish to express gratitude to Leonard Besemann and Heidi Eslinger for hosting and conducting the day to day care of this research trial, the North Dakota Agricultural Experiment Station, the Northern Plains Potato Growers Association and MN Area II Potato Research and Promotion Council, R.D. Offutt Co., Hoverson Farms, Enander Seed and Jorde Certified Seed for research funding and certified seed potatoes in support of processing research. Additionally, I am grateful for the assistance of Richard Nilles, Dr. Jose Rodriguez, and our hourly and graduate students, for help planting, maintaining, harvesting, and grading the trial.