Reliability of germination testing procedures and germination performance of stored Eucalyptus camaldulensis seed of different ages

Abstract

Eucalyptus camaldulensis Dehnh. is an important species for environmental and commercial forestry and there is a strong demand for seed. Stored seed must be tested in order to monitor losses in germination rate and vigour over time, which might adversely affect nursery recovery rates. Typically, seed storage facilities undertake germination testing in growth cabinets in which temperature and light are controlled. It is important to ensure that testing procedures are reliable; for example, the use of different germination cabinets should not affect the results. Here, we have assessed the germination performance of E. camaldulensis seedlots that have been stored for periods of 1, 6, 12 and 17 years, employing two germination cabinets routinely used for testing seed. A detailed experimental design was developed to determine the consistency of germination within and between germination cabinets. The normal practice of undertaking laboratory germination studies of limited size in a single germination cabinet does not appear to compromise the results. It is, however, important if multiple shelves are to be used within a cabinet, that an experimental design is employed so that adjustments can be made in across-shelf comparisons of germination capacity. Seed collected in 1985 and stored for 17 years had a significantly lower germination rate than younger seedlots.