Submitted to: Red River Valley Potato Growers Association Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/12/2003
Publication Date: 2/14/2003
Citation: Glynn, M.T., Sowokinos, J.R., Preston, D., Suttle, J.C., Hatterman-Valenti, H. 2003. The effect of moisture deficit on the development of "sugar-end defect" in russ burbank potatoes and subsequent reconditioning in storage. Proceedings Minnesota Area II Potato Research and Promotion Council and the Red River Valley Potato Growers Association Conference. p. 275-281.
Technical Abstract: Postharvest storage losses cost the potato industry hundreds of millions of dollars annually. One of the more serious physiological disorders affecting potato market quality is sugar-end defect. Sugar-end defect is a result of pre-harvest field stress that predisposes potatoes to accumulate excessive levels of reducing sugars during storage which in turn leads to chip darkening during processing. Because of its uncertain origin and unpredictable occurrence, little was known about the causes and management of this disorder. A collaborative research effort by scientists from the ARS East Grand Forks Potato Research Worksite, University of Minnesota, North Dakota State University, and the University of Minnesota Extension has been initiated to determine the preharvest causes of sugar-end defect and identify postharvest management strategies to minimize the severity and economic impact of this disorder. In this study, the effects of pre-harvest field moisture deficit (water stress) on postharvest development of sugar-end disorder were examined. Studies determined that, depending on the timing of water stress, two types of sugar-end disorder could be induced. Early moisture deficit during tuber formation resulted in the accumulation of sugars in the stem end of the tuber. This type of sugar-end was not reversible by any postharvest treatment tested. Mid-season moisture deficit resulted in a more dramatic accumulation of reducing sugars that also was more pronounced in the stem end of the tuber. Unlike early season stress, the mid-season induced sugar-end was readily reversed by postharvest reconditioning treatments. These results suggest that the severity of sugar-end defect in field-stressed tubers can be minimized and the financial loss to producers and processors reduced. The results also demonstrate a need to develop methods to differentiate the type of sugar-end present in harvested tubers in order to optimize storage management.