Risk factors

Incubation, cultivar and storage

The tuber’s physiological ageing speed, or incubation speed, differs with each cultivar. It is rated in the French catalogue of potato cultivars from 1: very rapid (highly susceptible to incubation) to 9: very slow.

The age of a tuber of a given cultivar at a given time increases in proportion to the length of time since its initiation (chronological age), and to the temperature at which it was stored after being harvested. Cultivars characterised by slow physiological development tolerate basic storage conditions.

The knowledge acquired concerning the physiological age of seed potatoes has found a practical application in low-temperature storage and the use of cold rooms (2 to 4°C). This provides high-quality seed potato tubers that are physiologically suitable for conventional planting.

Apart from physiological ageing, seed potatoes of some cultivars, stored at too low a temperature or air moisture, may suffer dehydration of the eyes which may totally or partially inhibit sprouting.