Provenance and seed mass determines the seed germination success of Eucalyptus ovata (Myrtaceae)

Abstract

Eucalyptus ovata is a medium size tree which grows from near sea level to sub-alpine regions in the south-east of Australia and is increasingly being used for woodland restoration in Tasmania. Given the wide altitudinal range of the species, we investigated whether a wet, cold stratification treatment enhanced seed germination of high altitude provenances. Open-pollinated seeds were harvested from five trees from a high and low altitude provenance within each of the five geographic regions from across E. ovata 's distribution in Tasmania. Chilling imbibed seeds at 5°C for three weeks had no effect on the overall proportion of viable seeds which germinated. There were, however, significant provenance differences in seed weight and the germination traits (i.e. proportion of viable seeds, germination rate and overall proportion germinated) which were variably linked to differences in altitude. Seed viability tended to increase with seed mass and provenance-level correlations amongst germination traits suggested that seeds from different provenances differed in germination vigour. These results indicate that provenance rather than a pre-treatment determines germination success of E. ovata seed, but these provenance differences are not predictable and that selection of heavier seeds may increase germination success in the nursery and in direct seeding applications.