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M A R C H 2 0 1 626 POTATO GROWER moulboard plow youll get 40 greater reduction break down faster and release Verticillium faster developing antago- nists faster resulting in breaking down Verticillium faster. Developing a qPCR Assay to Deter- mine Population Densities of Root- Lesion Nematodes Pratylen-chus Penetrans in Soils to be Planted to Potato Dr. Guiping Yan NDSU mentioned that the root-lesion nematode is a com- mon nematode pest of potato. Yield losses vary from 25-73. Pratylenchus penetrans is the more virulent. It is important because plant growth was negatively correlated with densities of P. penetrans The damage threshold is about 100 nematodes250 g soil. In an affected field in Norway the potato yield had been reduced by 50. There is an interaction with Verticillium wilt fungi resulting in the Potato Early Dying Syndrome. In her research Dr. Yan collected 50 samples of which 23 samples contained root lesion nema- todes. 12 samples were identified as P. scribneri and 11 as P. penetrans. Dr. Yan used carrot disk cultures to increase pure populations of P. penetrans. It is challenging to identify P. penetrans using traditional microscopic methods. Morphological differences from other Pratylenchus species are minor and there is a great variability of individual speci- mens within a population. Dr. Guiping Yan developed a qPCR Assay to identify and quantify P. penetrans in the soil. She found that much sequence varia- tion was found in ITS rDNA region. She stated that the consensus sequence will be used to design qPCR primers next year. Potato Improvement for the Northern Plains Dr. Susie Thompson NDSU said that the first objective of the breeding pro- gram was to release varieties to the industry She also has some material available in her breeding program with resistance to golden nematode and PVY. Dr. Thompson mentioned a few clones with positive characteristics such as ND8068-5Russ a russet with good storability and low sugar accumulation. It has an excellent frozen processing quality after 7 months storage. ND6002-1R a red round with smooth bright red tubers smooth eyes and bright white flesh. It is still early in the evaluation process. ND7799c-1 chips from 42oF storage. Soft Rot Bacteria Present in Northern Plains Potatoes Dr. Carol Ishimaru UMN mentioned that potato soft rot blackleg and stem rot affect potato production and storage by causing tuber and stem rots. There may be multiple causal agents varying by location. The disease is favored by wet conditions and water films create anaerobic pockets. Dr. Ishimaru commented that planting infected seed or poorly suberized seed decays after planting and results in The NPPGA Research Reporting Conference was very well attended.