The seedling seed orchards of Eucalyptus benthamii located in Deniliquin, New South Wales and Kowen, ACT produce improved seed, utilising selected families from natural populations. They also serve as part of a base population for breeding.
Establishment of the Eucalyptus benthamii seed orchards
Three seedling seed orchards of E. benthamii were established in 1995. Two sites near sites near Deniliquin, New South Wales and one site in Kowen, near Canberra in the Australian Capital Territory (ACT).
Originally established as trials to test for superior provenances, families and individuals, they were measured and selectively thinned in 2000, 2001 and 2002, converting them into seedling seed orchards. Selection was based on stem volume, straightness and branch characteristics, leaving only the best trees for seed production.
High quality E. benthamii seed is now being produced from these orchards for sale to plantation growers within Australia and overseas.
Deniliquin orchards site details
The Deniliquin seedling seed orchards incorporate between 50 and 55 families of E. benthamii sourced from the species’ limited and disjunct natural distribution west of Sydney, New South Wales. These populations are both isolated from each other and fragmented at the stand level due to urban development, therefore out crossing rates are expected to be much higher in the orchards compared with wild seed.
Deniliquin has an altitude between 90-100 metres above sea level with an average annual precipitation is 410 mm plus irrigation as required, equivalent to about 300-400 mm annually. The mean daily minimum temperate of the coldest month (July) is 3.4oC and the absolute minimum temperature is around -5.1oC.
Each orchard located in Deniliquin was originally established as a randomised complete block design withfour replicates per orchard. The family plot size was originally five trees, progressively thinned to one tree per plot by 2002, with plots of some of the poorest families removed completely.
Kowen orchard site details
The Kowen seedling seed orchard incorporates 48 families of E. benthamii sourced from the species’ largest natural population, the Kedumba Valley, west of Sydney, New South Wales. This population is both isolated from the few other natural stands of the species and limited in numbers. Outcrossing rates are expected to be much higher in the orchard compared with wild seed.
Kowen is situated around 600 metres above sea level with an average annual precipitation around 620 mm. The mean daily minimum temperate of the coldest month (July) is -0.2oC and the absolute minimum temperature is around -10oC. The orchard was originally established as a randomised complete block design with five replicates. The family plot size was originally five trees, progressively thinned to one tree per plot by 2001.
Seed from the Eucalyptus benthamii seedling seed orchards is available to be purchased by customers in Australia and overseas.