A P R I L 2 0 1 7 POTATO GROWER 11 western Minnesota. In 2016, seed maintenance and production, and field research trials were grown at nine locations. Five sites were irri- gated (Larimore, Inkster, Oakes, Park Rapids and Williston) and four were non-irrigated (Baker, Hoople, Crystal and Grand Forks). The research trials are important in identifying selections with high yield potential, disease and pest resistance, stress tolerance, and quality attributes. This summary reports the results from the 2016 Larimore Processing Trial. Thirty-six advancing dual-purpose russet selections and commercially acceptable cultivars were included in the trial planted on June 5 and 6. The field plot design was a random- ized complete block with four repli- cates; cultural practices typical of the growing area for Russet Burbank, including sprinkler irriga- tion, were used during the growing season. Rows were 36 inches apart, with a 12-inch within-row spacing. Vines were flailed on October 3 and the trial harvested from October 5- 12, with delays primarily due to rains and equipment breakdowns. Days to vinekill were about 120 (24 days fewer than in 2015), while days to harvest ranged from 120- 127. We typically flail within a day or two of harvest to mimic what many process growers are doing in terms of green digging; however, implications of green digging may be to increase the amount of Verticillium inoculum over time, and also increases the amount of storage management required immediately following harvest. Agronomic and tuber quality evalu- ations, yield and grade, and French fry quality are summarized in Tables 1, 2 and 3, respectively. Percentage stand ranged from 79 to 99%, with a mean of 92% (Table 1). Potato Virus Y (PVY) infected seed resulted in reduced stands for some entries., and several entries have strong dor- mancy. Vine sizes significantly dif- fered, as expected, and ranged from very small (scale of 1 to 5 with 1 being very small, to 5 being very large) for ND8068-5Russ, ND 113330-1Russ, ND092019C-4Russ, and ND070927-2Russ, to very large for ND091938BR-2Russ, ND1027 19B-1Russ, ND113100-1Russ, ND 113174B-2Russ, Bannock Russet, Dakota Trailblazer, and Russet Burbank. Early maturation is important for northern plains pro- ducers and vine maturities ranged from 1.0 (very early) to 4.0 (medi- um late), with a mean of 2.4. Stem numbers per plant is indicative of seed quality (physiological age and seed size), tuber eye number, and length of dormancy. Stem numbers ranged from 1.2 for ND081764B- 4Russ, to 2.5 for ND091933ABCR- 2Russ and ND113100-1Russ; the mean was 2.0. Optimum stem numbers for peak production of specific cultivars will generally be in the range of 1.5 to 3.0. Total yields were significantly dif- ferent, ranging from 157 cwt./acre for WND8624-2Russ to 480 cwt./acre for Russet Burbank (Table 2); the mean was 278 cwt./acre across the 36 entries. Yields were lower than in 2015, and can be explained by the short growing sea- son due to late planting for this site. Similarly, production of US No. 1s was less than in previous years. Yield of US No. 1s ranged from 99 cwt./acre for Umatilla Russet to 275 cwt./acre for Dakota Russet, while percentage US No. 1s ranged from 39% for Umatilla Russet to 86% for ND113065-2Russ, with means of 194 cwt./acre and 69%, respectively. The percentage of 6 to 10 ounce size tubers for clones was in the range of 7 to 22%, compared to 2015 when it was the upper 40 to mid-50 per- centage range. In 2016, the majori- ty of tubers were in the 4-6 ounce range, intimating that having a couple more weeks of growth could have shifted the majority into the 6-10 ounce grade. Early maturing selections, such as ND113065-1Russ and ND113065-2Russ had a high percentage of oversized tubers. Russet Burbank had 41% culls, which included misshapen tubers, ND050032-4Russ is the result of a cross between Dakota Russet and Dakota Trailblazer, combining attributes of both.