Heterosis test for Eucalyptus hybrid families including Eucalyptus urophylla×Eucalyptus grandis

ObjectiveIn order to selected elite Eucalyptus hybrid,comparisons on growth and resistance to Lepto-cybe invasa Fisher&La Salle of hybrid families with E. urophylla as female parent and E. grandis,E. camaldulensi,E. vaetarensis and E. tereticornis as parents.MethodHybrid families experimental forests were constructed with E. urophylla as female parent and crossing with E. grandis,E. camaldulensi,E. vaetarensis and E. tereticornis. Growth traits and re-sistance to L. invasa were tested.Result75.0%-100.0%hybrid families of E. grandis(male parent)crossed with E. uro-phylla showed heterosis. While only 50.0%hybrid families of E. urophylla by E. camaldulensis(male parent),E. vaetaren-sis(male parent)and E. tereticornis(male parent)showed heterosis. The growth of family X807(E. camaldulensis crossed with E. urophylla)was the biggest,and its volume was 56.81% bigger than open-pollinated families from female. But 50.0% of hybrid families were damaged by L. invasa. In addition ,the growth of X420(E. grandis crossed with E. uro-phylla)ranked the second,and its volume was 35.48%bigger than female open pollinated family(X814). Based on indi-vidual volume and resistance to L. invasa ,five hybrid families that were better than open-pollinated families from female(X814)were selected. Their volume growth were 11.11%-35.48%higher than open-pollinated families from female at the age of 3.4 years old,and suffered no damage from L. invasa.ConclusionThe hybrid families with E. grandis, E. camaldulensis,E. wetarensis and E. tereticornis as male parent and E. urophyllas as female parent have heterosis. The heterosis of hybrid family with E. grandis as male parent is the highest. Elite individual from families can be transformed clonally,tested and utilized.