A new form of low-temperature injury in potatoes

Summary

A so-called “mahogany rot”, for which the name “internal mahogany browning” is proposed, is caused by long exposure to medium low temperature. Chippewas and Katahdins stored at 32° F. through the winter exhibited the reddish-brown discoloration by March. No injury was shown by the same varieties stored at 38° F., or by Green Mountains stored at 32° F. Leaf roll aggravated the injury in Chippewas.

Exposure to lower temperatures for short periods produced the usual freezing injury in all varieties. This injury occasionally exhibited a fluorescence, and this fluorescence was more bluish than the greenish fluorescence of internal mahogany browning. Leaf roll accentuated the greenish fluorescence, so that it was indistinguishable from the fluorescence of tubers infected by bacterial ring rot.

Internal mahogany browning may reduce the stand and yield rate of a field planted with seed showing the injury.