Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32J U L Y / A U G U S T 2 0 1 6 POTATO GROWER 13 n North Dakota and Minnesota acid and protein concentrations in potato tubers. N fertilization influence chip color and reducing sugars (RS) con- centrations by interfering with tuber chemical maturation. The aim of the study is to explore the effect of N uptake and utilization, on expression of several enzymes related to reducing sugar accu- mulation like acid invertase and UGPase. The effect of N fertilization on expression of various cellular enzymes will be investigated. The main empha- sis will be on the enzymes related to ini- tial N uptake and reducing sugar accu mulation. Preliminary results on three contrasting cultivars namely Russet Burbank, Dakota Russet and Easton grown at 120, 240, and 360 lb/ac nitrogen fertilizer regimes showed significant differences in terms of total soluble protein content in the cells. Samples will be analyzed for total reducing sugars and key enzymes to better understand the chemical maturity and long term stora- bility. Varieties that are more efficient at cap- turing soil N during the entire growing season can decrease N leaching and denitrification losses. It is imperative to identify potato varieties with high NUE, which required low N fertilization but efficiently utilize available N. Increasing plant N use efficiency (NUE) is essential for the development of sustainable agri- culture. 2. Study the predictive markers related to abiotic stresses and reducing sugar accumulation in potato tubers grown at different geographical location. Predictive biomarkers have been devel- oped for abiotic stresses (mainly A-I and A-II protein of UGPase) and reducing sugar accumulation potential (mainly UGPase and Acid Invertase enzymes). Predictive biomarkers for reducing sugar accumulation potential during long term cold storage have been used for several years to help various potato breeding programs. Initial results on distribution of A-I and A-II isozymes of UGPase have shown close association with the abiotic stress tolerance in sev- eral potato cultivars. The current study is designed to first study the levels of reducing sugars and key enzymes in potato tubers grown at three geographically different locations. Further study will be focused on the expression of A-I and A-II isozymes of UGPase to develop predictive biomark- ers for abiotic stresses which causes sugar end development in tuber. Russet Burbank has been grown at three geo- graphical locations (central North Dakota, Central Minnesota and south- ern Minnesota). Tuber samples have been collected in replicates to represent 40 acres from each site.