Morphological analysis to identify the pollen parent of an ornamental interspecific hybrid eucalyptus

Eucalyptus 'Urrbrae Gem' is an attractive amenity tree which is believed to be a spontaneous F-1 hybrid with Eucalyptus erythronema var. erythronema t he known female parent. Previous observations based on adult morphology led to suggestions that either E. gomphocephala or E. stricklandii could be th e male parent. Multivariate analysis of 54 adult morphological characters p laced E. 'Urrbrae Gem' between E. erythronema var. erythronema and E. stric klandii, with minimum spanning tree values of 0.21 and 0.27, respectively. Controlled hybridisation between E. erythronema var. erythronema and both E . stricklandii and E. gomphocephala were undertaken, and the resulting seed lings were compared to each other, and to open pollinated seedlings of the putative parent species and of the F-1 and second generation E. 'Urrbrae Ge m' trees. Based on 14 morphological characters, seedlings clustered into ei ght groups, with E, erythronema var. erythronema x E. stricklandii seedling s most similar to open pollinated seedlings of the Fl and second generation E. 'Urrbrae Gem' trees. In contrast, E. erythronema var. erythronema x E. gomphocephala seedlings clustered into a number of groups, with the majorit y close to E. gomphocephala open pollinated seedlings. The results indicate d that E. stricklandii is the male parent of E. 'Urrbrae Gem'. (C) 2001 Els evier Science B.V. All rights reserved.