The effect of vine kill method on vine kill, tuber skinning injury, tuber yield and size distribution, and tuber nutrients and phytonutrients in two potato cultivars grown for early potato production

Authors: Boydston, Rick; Navarre, Duroy - Roy; Collins, Harold; CHAVES-CORDOBA, BERNARDO - Washington State University

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2017
Publication Date: 11/5/2017
Citation: Boydston, R.A., Navarre, D.A., Collins, H.P., Chaves-Cordoba, B. 2017. The effect of vine kill method on vine kill, tuber skinning injury, tuber yield and size distribution, and tuber nutrients and phytonutrients in two potato cultivars grown for early potato production. American Journal of Potato Research. 95:54-70. https://doi.org/10.1007/s12230-017-9614-0.
DOI: https://doi.org/10.1007/s12230-017-9614-0

Interpretive Summary: Baby potatoes are produced by harvesting tubers much earlier (approximately 60 to 85 after planting) than full season potatoes. Killing the top growth of potatoes prevents tubers from becoming oversized, induces tuber maturity, accelerates skin set, improves tuber release from the vine, reduces incidence of fungal and insect infestations, and reduces trash-related harvesting problems. Vine kill at earlier growth stages can be challenging since the vines are still growing rapidly and have not begun to naturally senesce. Obtaining complete vine kill is important for harvest efficiency and tuber skin set as early harvested, immature tubers are highly susceptible to skinning injury. Sixteen vine kill programs were tested on two potato cultivars Bintje and Ciklamen over a three year period. Mechanical, chemical, and physical (flaming) vine kill methods, and sequential combinations of the three were all effective in killing rapidly growing potato vines of Bintje and Ciklamen. Rolling and crimping did not kill vines as completely and more vine regrowth occurred than with most other methods tested. Tuber skinning injury was greatly reduced when harvesting at 4 weeks after initial vine kill than at 2 weeks. Glufosinate, a slower acting desiccant, tended to average less tuber skinning injury when harvested earlier. Total tuber yield and size distribution were similar among most vine kill treatments, with the exception of the earlier applied glufosinate treatments, which tended to reduce total yield, but still yielded a similar mass of desired 25 to 35 mm diameter tubers. Tuber nutrient and phytonutrient content were generally similar among vine kill treatments. Tuber phenolic content tended to be greatest in earlier-applied glufosinate treatments. Nonchemical vine kill methods, chemical vine kill methods, and combinations of methods were identified that killed vines well, allowed for adequate tuber skin set, and yielded similar amounts of 25 to 35 mm diameter tubers.

Technical Abstract: Sixteen vine kill programs were tested on Bintje and Ciklamen potato cultivars grown for early potato production over a three year period near Paterson, Washington. Mechanical (flail chopping, flail chopping and undercutting), chemical (glufosinate, diquat, sulfuric acid, carfentrazone, pyraflufen-ethyl), and physical (flaming) vine kill methods, and sequential combinations of the three were effective in killing rapidly growing potato vines of Bintje and Ciklamen. Rolling and crimping did not kill vines as completely and more vine regrowth occurred than with most other methods tested. Tuber skinning injury was greatly reduced when harvesting at 4 weeks after initial vine kill than at 2 weeks. None of the vine kill programs were able to hasten skin set enough to allow tubers to be harvested at 2 weeks after initial vine kill without significant tuber skinning injury. Glufosinate treatments that were applied several days earlier than other initial vine kill treatments tended to average less skinning injury at the early harvest possibly due to more time elapsing between initial vine kill and harvest. Total tuber yield and size distribution were similar among most vine kill treatments, with the exception of the earlier applied glufosinate treatments, which tended to reduce total yield, but still yielded a similar mass of desired 25 to 35 mm diameter tubers. Tubers from vine-killed plots tended to average greater N, P, K, Fe, and Ca content than tubers from non-killed control plots of both cultivars. Tuber ascorbate levels were also greater in non-killed controls, whereas total phenolic content tended to be greatest in earlier-applied glufosinate treatments. Nonchemical vine kill methods, chemical vine kill methods, and combinations of the two were identified that killed vines well, had low skinning injury at the 4 week harvest, and yielded similar amounts of 25 to 35 mm diameter early potato tubers. Nutrient and phytonutrient content of tubers were similar among vine kill treatments.