Transient heat stress during tuber development alters postharvest carbohydrate composition and decreases processing quality of chipping potatoes

Authors: Busse, James; WIBERKET-BRADFORD, AMY - University Of Wisconsin; Bethke, Paul

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2018
Publication Date: 11/9/2018
Citation: Busse, J.S., Wiberket-Bradford, A.E., Bethke, P.C. 2018. Transient heat stress during tuber development alters postharvest carbohydrate composition and decreases processing quality of chipping potatoes. Journal of the Science of Food and Agriculture. https://doi.org/10.1002/jsfa.9473.
DOI: https://doi.org/10.1002/jsfa.9473

Interpretive Summary: Heat stress limits productivity of cool-weather crops such as potato and may degrade crop quality. Chipping potatoes must pass stringent raw product quality standards in order to produce potato chips that meet consumer expectations for appearance and taste. Potatoes that do not produce high quality chips can be rejected at processing plants, and this possibility introduces a significant financial risk to producers and may lead to supply problems for processors. Stem-end chip defect is a tuber quality defect of chipping potatoes that appears erratically across years and locations. The present study was undertaken to determine if transient heat stress during the period of potato enlargement is sufficient to cause stem-end chip defects. Heat stress for 7 and 14 days increased the severity of chip defects. Heat stress also resulted in undesirable changes in tuber dry matter content and sugar contents at the tuber stem end. Differences in responses to heat stress were observed between four varieties of chipping potatoes. It is suggested that potato growers should select varieties with heat stress tolerance to mitigate detrimental effects of high temperatures on chipping potato quality.

Technical Abstract: Adverse air and soil temperatures are common abiotic stresses that occurs frequently in many parts of the world and vary widely in duration and magnitude. Heat stress limits productivity of cool-weather crops such as potato (Solanum tuberosum) and may degrade crop quality. Chipping potatoes must pass stringent raw product quality standards in order to produce finished products that meet consumer expectations for appearance and taste. Stem-end chip defect is a localized discoloration of chips at a position that corresponds to the vascular and adjacent ground tissue at the tuber basal end. To test the hypothesis that stem-end chip defect is caused by transient heat stress during the growing season, chipping potatoes were grown under controlled environment conditions with 22°C days and 18°C nights. Heat stress periods with 35°C days and 29°C nights were imposed 91-100 days after planting and lasted for 3, 7 or 14 days. Plants were returned to control conditions after a single heat stress period and were allowed to senesce naturally. At harvest and 1, 2 and 3 months after harvest, potato tubers were evaluated for glucose, fructose, sucrose and dry matter content at the basal and apical ends and for defects in fried chips. Heat stress periods of 7 and 14 days increased reducing sugar content in the tuber basal but not apical end, decreased dry matter content, and increased the severity of chip defects. Basal-end reducing sugar contents and stem-end chip defects were greater 1 and 2 months after harvest than at harvest or 3 months after harvest. Differences in responses to heat stress were observed between four varieties of chipping potatoes and it is suggested that planting varieties with tolerance to transient heat stress may be an effective way to mitigate detrimental effects on chipping potato quality.