M A Y / J U N E 2 0 1 7 10 POTATO GROWER 2016 Chip Processing Trial Results Hoople, North Dakota by Dr. Asunta (Susie) Thompson, NDSU Potato Breeder A major goal of the North Dakota State University (NDSU) potato breeding program is the breeding, selection, evaluation, development, and release of chipping potato culti- vars with high yield potential, resistance to abiotic and biotic stres- sors, improved chip processing quality attributes, and possessing cold-sweetening resistance. Improved chip processing cultivars provide opportunities for enhanced economic and environmental sus- tainability for potato producers and the chip industry, and the potential for superior quality products for consumers. This report summarizes the NDSU Chip Processing Trial, hosted by Lloyd, Steve and Jamie Oberg, north of Hoople, North Dakota. The replicated (4) trial was planted on May 18, 2016, using an assist-feed planter. Cultivar specific manage- ment practices typical of chip pro- cessing production fields in the northern Red River Valley were used. The Hoople trial is non-irri- gated, and an irrigated chip trial was grown at Hoverson Farms. The summer was marked by extremely high rainfall, with that field receiv- ing between 36 and 42 inches, high winds, and damaging hail. Vines were desiccated on about September 1, and the trial was harvested on September 28 with a single-row Grimme harvester. Days to dessica- tion were about 104, while days to harvest were 132. Agronomic characteristics, yield and grade, and chip processing quality traits are summarized in Tables 1-3. We will be processing the long-term storage samples of this material on about June 7. Our most advanced chip- ping genotypes are pictured and described at the end of the article. We hope this summary will serve as a reference for potato producers, research and extension personnel, industry representatives, and con- sumers. Fifteen advancing selections were compared to nine commercially acceptable chip processing cultivars. The selections represent a diverse set of germplasm, with several wild Solanum species including S. phureja, chacoense, etubersum, and berthaultii, represented in the pedigree of many. In addition to attributes such as cold sweetening resistance, high specific gravity, Colorado pota- to beetle and insect resistance, resistance to viruses, late blight and water rots, this diverse material may result in selections with a smaller tuber size profile, some tubers may be flattened, have deeper eyes or ends (both stolon and apical), and generally be a bit rougher or lower yielding; often there is an increase in tubers set per plant. Percentage stand ranged from 69 to 100 (Table 1). ND113060-1 had the poorest emergence; however, PVY presence was only noted in one plot. Parents are Ivory Crisp x ND7519-1, so seed piece decay and/or long dormancy would not be expected. Vine size ranged from small (2.3 for ND102922C-3) to large (5.0 for Dakota Diamond). The mean vine maturity was 3.3, with a range of 1.1 (very early) for ND7818-1Y and ND102631AB-1, to 4.0 for many. All of the industry standards had a maturity rating of 3.5 or greater, while the mean rating for the advancing selections was 2.9, a reflection of the breeding programs effort to identify high yielding early maturing genotypes suited for our short growing season. Stems per plant ranged from 1.0 for Waneta to 2.8 for ND8305-1, with a mean of 2.0. Tuber numbers per plant aver- aged 7.2, with a range of 5.0 for Waneta to 10.8 for ND102922C-3. Yield and grade for all entries is summarized in Table 2. Mean yield was 214 cwt./acre, with a range of 103 cwt./acre for ND113060-1, to 298 cwt./acre for Atlantic. Reduced yield and a smaller tuber size profile can be attributed to the heavy rains and hail damage to the plants. The mean percentage A-sized tubers (4- 10 ounce) was 71%, with a range of 8% for ND102922C-3, to 71% for Waneta (ND7799c-1 followed at 70%). Percentage undersized tubers (0-4 ounces) ranged from 15% for Ivory Crisp to 91% for ND102922C- 3, with a mean of 47%. There were few selections with many oversized