Seed potato physiological age and crop establishment

Abstract

Seed potato physiological age progressively advances with time (chronological age), but is also influenced by temperature during storage. In this work, different combinations of constant temperatures (2, 8 and 20°C) were applied to 'Bondi' and 'Fraser' seed potatoes at different times during the storage period. By the end of storage, potatoes differed in the temperature sum they had been exposed to or the timing and duration of warmer periods. The range of accumulated temperature was 180 to 3,600 °Cd. Any sprouts produced during storage were removed before being planted at 20°C at one month intervals from 4-10 months after storage. In most cases delaying planting (chronologically older seed) resulted in earlier emergence and an increase in the number of stems emerged. Increased storage temperature from 2-8°C (thermally older seed) had no effect. Prolonged storage of seed potatoes at 20°C gave a significant reduction in the fraction of plants that emerged and produced a decline in the number, growth and stage of development of the stems emerged, but only when the seed potato had accumulated over 3,060 °Cd for both cultivars. It seems that using expensive cool storage in winter in Canterbury, with cool winter ambient temperatures, is unnecessary for crop establishment and by inference subsequent crop production.