Location: Vegetable Crops Research Unit
Title: Stem-end chip defect in response to high temperature stress Authors
Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 28, 2012
Publication Date: August 13, 2012
Citation: Bethke, P.C., Wang, Y., Busse, J.S., Bussan, A.J. 2012. Stem-end chip defect in response to high temperature stress [abstract]. Potato Association of America Proceedings. Paper No. 020. Technical Abstract: Stem-end chip defect is a serious quality concern for the potato chip industry. Chips with stem-end chip defect are unacceptably dark along the vasculature at the tuber stem end and in adjacent tissues. Tubers that produce stem-end defect chips are undesirable to processors and increase financial risk to growers. The causes of stem-end chip defects are not known. Defects occur erratically, with a high incidence of defects in some years and low incidence in others. Predicting which fields will have stem-end defect tubers has proven to be difficult, and often the presence of defect tubers is not apparent until after harvest. Determining the cause or causes of stem-end chip defect will facilitate the development of predictive tools that will help growers and processors assess the likelihood that stem-end chip defects will impact the quality of the crop. Potato plants were grown in temperature-controlled greenhouses to assess the affect that transient periods of heat stress has on stem-end chip defect incidence and severity. Two-week long periods of warm days (30°C) increased the incidence of severe stem-end chip defect in one of two years. Two-week periods of hot days (35°C) and warm (30°C) or cool nights (18°C) increased the incidence of severe stem-end chip defects in both years treatments were implemented. Severe stem-end chip defect tubers were observed with low frequency at harvest regardless of stress treatment. Tuber defect incidence increased to 33% or more after three months of storage at 13°C for 35°C daytime heat stress treatments, but not for the control treatment. These data indicate that high temperatures may be contributing to stem-end chip defect formation.