E. deglupta progeny trial two years old, Kunjingini

1976

E. deglupta progeny trial two years old, Kunjingini

A half-sib progeny trial/seed orchard was established at Kunjingini west of Wewak in the East Sepik District in 1974. The progeny were raised in Bulolo and were part of the half-sib seedlings raised for the seedling seed orchard in Bulolo. The design at Kunjingini was meant to be random single tree plots, each surrounded by a buffer of routine planting stock. That is consecutive half-sib rows would have a row of routine stock in between and each half-sib within a row would have routine stock either side of it within the row. However no routine stock was available from Wewak or Maprik nurseries, so the buffers were not established. This would be an issue later as the first thinning was for the planned removal of only the buffer trees thus retaining all of the half-sibs for continued measurement and seed collection.

Actual thinning was carried out by removal of the poorest stems on an individual basis. Ideally, thinning should have been carried on a family basis, removing only the individuals comprising the families with the poorest average family performance across the trial.

Above and left: E. deglupta half-sib progeny trial/half-sib seedling seed orchard at Kunjingini, age two years in 1976 just prior to thinning. Neville Howcroft is in the top right photograph. Design was singletree plots randomly arranged. There were marked improvements in straightness and bole cylindricity in the progeny. At this location and age, the bark was not showing the typical smooth multi-coloured appearance that would be seen in New Britain. Narrow sense heritability for wood density using parent offspring regression (n=74) = 0.54, using half-sib families (n=28 families) = 0.35. Narrow sense heritability for diameter growth (n = 38 families) = 0.64.