Testing tree seeds for vigor: a review

Abstract

This review examines the use of vigor tests for tree seeds. It suggests that precise evaluations of these tests and their application with seeds of woody plants is not yet possible. This is due to the wide genetic variation, primarily manifested in variable maturity and dormancy, that exists in most tree seed lots. Sensitive measurements of germination rate during standard germination tests have proved to be just as good, if not better, than any vigor test in judging the quality of seed lots. Accelerated aging, leachate conductivity, and germination rate all show promise, but extensive tests of field emergence are needed to validate the laboratory test procedures and interpretation. The evolution of vigor testing in agricultural seeds has been a slow, arduous, and still unfinished process. Reaching agreement on a definition for "seed vigor" and which tests are suitable for each species has been difficult. The process still continues, however, as new methods are devised and old ones are improved. Users of tree seeds (foresters, nursery managers, horticulturists, etc.) perceive a need for vigor testing of tree seeds and have encouraged tree seed researchers to pursue that goal. This review presents the published research on vigor testing of tree seeds, some unpublished data, and suggests which vigor tests show promise for operational use with tree seeds.

Citation

Bonner, F.T. 1998. Testing tree seeds for vigor: a review. Seed Technology. 20(1): 5-17.