Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 7, 2013
Publication Date: June 15, 2013
Citation: Thornton, M.K., Lee, J., John, R., Olsen, N., Navarre, D.A. 2013. Influence of growth regulators on plant growth, yield, and skin color of specialty potatoes. American Journal of Potato Research. 90:271-283. Interpretive Summary: We report how three growth regulators influenced six specialty potato cultivars qualities (plant height, incidence of foliar injury, tuber surface color, tuber appearance, etc.) at harvest and after controlled post-harvest storage. 2,4-D (2,4-dichlorophenoxyacetic acid) treated ‘Red LaSoda’ and ‘TerraRosa’ tubers had improved surface color compared to control tubers after harvest and post-harvest storage. Additional work is needed to understand how some growth regulators improve potato surface color and how minor color differences influence consumer-purchasing decisions.
Technical Abstract: 2,4-D has been used since the 1950’s to enhance color in red-skinned potatoes, but there is little research on the potential use of other plant growth regulators to improve tuber skin color in the wide range of specialty potatoes now available on the market. Field trials conducted at Parma, ID in 2009 and 2010 evaluated the effect of foliar applications of 2,4-D, NAA, and LPE on plant height, foliar injury, tuber yield, size distribution, and skin color of six specialty potato cultivars. Skin color was rated visually and via HunterLab colorimeter at harvest, and again after storage (130 days in 2009 and 90 days in 2010) at 4°C and 95% R.H. 2,4-D caused slight foliar injury and reduced tuber size in all cultivars. It also increased visual skin color rating in the red-skinned cultivars ‘Red LaSoda’ and ‘TerraRosa’ at harvest and after storage, and influenced incidence of pink coloration around the eyes of ‘Yukon Gem’ tubers, but did not affect color of blue/purple-skinned cultivars. NAA and LPE did not consistently influence plant growth, yield, tuber size or visual skin color in any cultivar. Colorimetric evaluations mostly agreed with the visual ratings, and indicated that storage significantly altered skin color in all cultivars, regardless of growth regulator treatment.