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Photo by Andy Robinson, NDSU/UMN

Potato cultivars or selections included in this report were selected from recently released cultivars, advancing selections with release potential (numbered lines progressing through the trial process), or cultivars that are new to the U.S. Standard potato cultivars used by growers served as checks. For comparison, studies conducted in 2019 evaluated red- and yellow-skinned fresh potatoes (https://z.umn.edu/Potato2019).

In 2020, two trials were conducted to identify traits of red- and yellow-skinned potato cultivars and advanced selections at Hoople, N.D. Nineteen red-skinned cultivars and 30 yellow-skinned cultivars were evaluated. Plots were established in a commercial, nonirrigated potato field utilizing common potato-production practices. The authors acknowledge J.G. Hall and Sons for hosting these trials.

Prior to planting, urea at 120 pounds of nitrogen (N) per acre was broadcast and incorporated. A randomized complete block design with four replicates was utilized. Seed tubers were hand cut to approximately 2-ounce seed pieces prior to planting; an exception was the cultivar Obama, which was planted using whole
seed tubers.

Tubers were planted on May 21, 2020, in a single row with 9-inch within-row spacing. Plots were 3 feet wide and 30 feet long.

A majority of the plants emerged by June 12 in both trials. Stand and stem counts on 10 plants in a row in each plot was taken on July 9. Vine length was measured on three plants from the base of the plant to the vine tip on Aug. 12.

Vigor evaluation was completed on Aug. 12. A rating of 1 indicated least vigor and 5 greatest vigor. Vines were desiccated on Aug. 21 and 28 with diquat. Plots were harvested on Sept. 10 and 11 with a single-row plot harvester.

After harvest, potatoes were stored at 55 F until grading. The tuber size profile distribution was determined by sorting all potatoes harvested into C size (less than 1.875 inches), B size (1.875 to 2.25 inches), A size (2.25 to 3.5 inches) and Chef size (greater than 3.5 inches). Total yield is a summation of C + B + A + Chef.

The agronomic data presented in Tables 1 and 2 were analyzed statistically. These analyses allow the reader to ascertain, at a predetermined level of confidence, if the differences observed among cultivars/selections are reliable or if they might be due to error inherent in the experimental process.

The LSD (least significant difference) values beneath the columns apply only to the numbers in the column in which they appear. If the difference between two cultivars/selections exceeds the LSD value at 0.05 or 0.10, it means that with 95% or 90% confidence, respectively, the higher-yielding cultivar/selection has a significant yield advantage. When the difference between two cultivars/selections is less than the LSD value, no significant difference was found between the two under these growing conditions.

The CV stands for coefficient of variation and is expressed as a percentage. The CV is a measure of variability in the trial. Large CVs mean a large amount of variation that could not be attributed to differences in the cultivars/selections.

The data provided does not indicate endorsement or approval by the authors, or NDSU Extension or University of Minnesota Extension. Reproduction of the tables is permissible if presented with all the same information found in this publication (meaning no portion is deleted and the order of the data is not rearranged).

The authors acknowledge the contribution of cultivars and advanced selections for this work from the breeding programs at North Dakota State University, University of Minnesota, U.S. Department of Agriculture-Agricultural Research Service, Colorado State University, University of Wisconsin, University of Maine, Michigan State University, EBE Farms, Northern Konstar Potatoes, Parkland Seed, Real Potato, Solanum, Southern Potato and SunRain.

Figure 1. Daily rainfall from May 21 to Sept. 11, 2020, from the North Dakota Agricultural Weather Network weather station near Crystal, N.D.

Table 1. Agronomic performance and graded yield of red-skinned potato cultivars/selections near Hoople, N.D., 2020.

¹ Stand count was taken on July 9 (seven weeks after planting) by counting every emerged plant and dividing by the number planted.
² Stems per plant were counted on 10 plants on July 9 (seven weeks after planting) and are shown as the average number of stems per plant.
³ Vine length was measured on three plants from the base of the plant to the vine tip on Aug. 12.
⁴ Vigor evaluation was completed on Aug. 12 (12 weeks after planting). A rating of 1 indicated least vigor and 5 greatest vigor.
⁵ Potatoes were sorted on a Kerian Speed sizer as C = less than 1.875, B = 1.875-2.25, A = 2.25-3.5 and Chef = greater than 3.5 inches.

photo by Andy Robinson, NDSU/UMN

Table 2. Agronomic performance and graded yield of yellow-skinned potato cultivars/selections near Hoople, N.D., 2020.

¹ Stand count was taken on July 9 (seven weeks after planting) by counting every emerged plant and dividing by the number planted.
² Stems per plant were counted on 10 plants on July 9 (seven weeks after planting) and are shown as the average number of stems per plant.
³ Vine length was measured on three plants from the base of the plant to the vine tip on Aug. 12.
⁴ Vigor evaluation was completed on Aug. 12 (12 weeks after planting). A rating of 1 indicated least vigor and 5 greatest vigor.
⁵ Potatoes were sorted on a Kerian Speed sizer as C = less than 1.875, B = 1.875-2.25, A = 2.25-3.5 and Chef = greater than 3.5 inches.

Funding for this publication was made possible by the U.S. Department of Agriculture’s (USDA) Agricultural Marketing Service through grant 19-439. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA.

This work was supported by funds from the U.S. Department of Agriculture, National Institute of Food and Agriculture grant 2019-34141-30284.

NDSU does not endorse commercial products or companies even though reference may be made to tradenames, trademarks or service names.