Genetic parameters of essential-oil traits for Eucalyptus bosistoana

A Eucalyptus bosistoana breeding trial established in New Zealand to select plants with improved growth and wood properties was assessed for essential-oil traits. Mature leaves of 8-year-old E. bosistoana were collected from 1901 trees representing 85 families. Twenty compounds were quantified in these samples. Heritability estimates (h2) of the quantified essential-oil compounds ranged from 0.06 to 1.14, with the most abundant compounds 1,8-cineole, aromadendrene and the unidentified compound 8 showing the highest h2 of 0.78, 1.14 and 0.59, respectively. Total oil content of the leaves had moderate (0.25) heritability. The estimated negative correlation between total oil content and 1,8-cineole concentration at the phenotypic and genetic levels (rp = –0.44 and rg = –0.70, respectively) implies that families with higher-quality oil had less oil in the leaves. 1,8-cineole was genetically negatively correlated with myrcene (rg = –0.74), α-pinene (rg = –0.71), linalool (rg = –0.90), aromadendrene (rg = –0.94), trans-pinocarveol (rg = –0.75) and the unknown compounds 3 (rg = –0.91), 6 (rg = –0.83), 8 (rg = –0.88) and 9 (rg = –0.75). Seven of the 85 families had breeding values consistent with the standard commercial oil-quality requirement of over 70% 1,8-cineole. The results indicate that a breeding program could aid essential-oil production from E. bosistoana.