Other cultivars in this study had little difference in skin color among growth regulator treatments at harvest and after storage. In ‘All Blue’ and ‘Purple Pelisse’, even though there were a few significant timing by growth regulator treatment interactions in the colorimetric evaluations, results were not evident in the visual color ratings. This may have been due to their dark (deep blue/purple) skin color, making it difficult to visually compare the results among the growth regulator
treatments and the control. Foliar application of 2,4-D increased the incidence and intensity of pink coloration around the eyes on tubers of ‘Yukon Gem’ compared to the control
tubers. These observations point to the fact that 2,4-D may stimulate pigment production in cells that normally do not
express this characteristic. However, it is unlikely that consumers would notice the slight increase in incidence or intensity of pink coloration reported here, and the use of 2,4-D for
that purpose would not be recommended.