The Effect of Storage Time, Temperature and Container on the Viability of the Seed of Four Pine Species

Abstract

SYNOPSIS Seeds of four pines, Pinus elliottii, P. patula, P. radiata and P. taeda, each represented by three stock numbers, were stored in linen bags and PVC containers at room temperature, 2 to 3°C and −16°C for 25 years. Germination capacity and dormancy per cent were measured periodically by actual germination and tetrazolium testing. Room temperature cannot be recommended for storing the seed beyond two years, although the seed of P. radiata deteriorates much more slowly than that of the other three species and still averaged 65 % germination capacity after 10 years. Refrigeration temperature or cold storage will maintain a high viability in all species for 20 years, but cold storage is essential if seed is to be stored for periods in excess of that time. A PVC container is more efficient than a linen bag, particularly at low temperatures for long periods of storage. as it maintains a more uniform moisture content in the seedlot. However, container made little difference to the viability of room-temperature stored seed for short-term storage. Tetrazolium testing became increasingly unreliable as the seed stored at room temperature and in a refrigerator aged. It was still effective after 25 years for seed stored at −16 °C in PVC containers. Seeds of all four species stored at −16 °C in PVC containers for 25 years gave rise to perfectly normal seedlings upon germination and raising in the nursery for field planting.