Vine-Kill Treatment and Harvest Date have Persistent Effects on Tuber Physiology

The quality of potato (Solanum tuberosum) tubers coming out of storage depends on the state of the tubers going into storage. Experiments determined the effects of vine-kill treatment and harvest date on the post-harvest physiology of potato tubers stored for up to 12 weeks. Potato cultivar Russet Burbank grown in central Wisconsin was harvested in late July when tubers were immature, in late August, and in early September after complete natural senescence of vines. Prior to the first two harvests, vines were either desiccated with diquat dibromide or were untreated. Data were collected at harvest and in storage for skin set, tuber respiration rate, and tuber sucrose, glucose, and fructose contents. Skin set at harvest was increased by use of the desiccant at the early harvest date, but not at the middle harvest date. Early harvest without vine kill resulted in elevated tuber bud-end glucose contents in storage. Early harvest with vine kill treatment resulted in increased rates of respiration in storage that persisted through December. Neither tuber sucrose nor glucose content 6 weeks after harvest was a good predictor of tuber glucose content 12 weeks after harvest. These data demonstrate that vine-kill treatment and tuber maturity at harvest have long-term effects on tuber quality.