Influence of low growth temperatures on physiological age of seed potatoes

In a controlled climate study including two Norwegian potato cultivars, the effect of low propagation temperatures on the physiological age of seed tubers was measured by adopting a newly developed physiological age index (PAI). The growth vigour and yielding potential of the tubers were also studied. Cv. Beate was physiologically older than cv. Troll at three and nine months after haulm killing. In both cultivars, physiologically oldest tubers originated from the lowest propagation temperatures, even though these tubers were the least mature at harvest. The observed age differences, however, were small and did not affect the growth vigour and production capacity.