Location: Vegetable Crops ResearchTitle: Stem-end chip defect: trial summary from 2009-2012 Author
Submitted to: American Journal of Potato Research
Publication Type: Proceedings
Publication Acceptance Date: 3/29/2013
Publication Date: 2/1/2014
Citation: Bethke, P.C., Dickman, L., Wang, Y., Bussan, A. 2014. Stem-end chip defect: trial summary from 2009-2012. American Journal of Potato Research. 91(1):32-74. Interpretive Summary:
Technical Abstract: Stem-end chip defect is characterized by dark fried color along the vascular and adjacent tissues at the basal (stem) end of potato chips. Stem-end defect chips are unacceptable to chip processors and stem-end defect tubers may be rejected at processing plants. Stem-end chip defect occurs erratically over years and locations. Several trials have been conducted with the objectives of evaluating the environmental causes of stem-end chip defect, investigating resistance of cultivars to defect development, and assessing defect incidence and severity of cultivars at multiple locations. These trials include: a national survey from 2009 to 2011 on commercial farms in three states, a three-year study in the climate-controlled UW Biotron from 2010 to 2012, as well as an additional field study in 2012 across seven US states. The results acquired so far are summarized as follows: stem-end chip defect severity and incidence were closely and linearly related (Pearson's correlation coefficient of 0.93, p-value <0.01); defect severity at harvest indicated how likely it was that preconditioning in storage would reduce defect incidence; heat stress for 14 days, with daytime temperature at 35°C, resulted in severe defect development during storage at 13°C; some cultivars are more susceptible to stem-end chip defect development than others and accumulate higher amounts of glucose on the stem end of stored tubers.