New results are in on an experiment in a commercial orchard near Ardmona, Australia, to test the biological limits of pear production by sustaining exceptionally high yields of good quality, canning-size pears (larger than 65 mm or 2.5 inches).
In an earlier Good Fruit Grower article (“Manage pears for higher yields,” September 2015), we reported how Bartlett trees on Tatura trellis produced 123 tonnes per hectare/bins per acre canning-grade pears in 2014-15 by changing tree management rather than the rootstock.
The following season (2015-2016), the trees produced 114 tonnes per hectare/bins per acre.
Tree management included winter pruning to develop short, horizontal fruiting wood containing spurs and short laterals with terminal fruit buds.
Trees were sprayed twice with the growth regulator paclobutrazol (PP333) in early spring to control tree vigor and improve fruit set and fruit growth.
Other management practices were repeated from the previous season.
Two foliar sprays of paclobutrazol reversed the effects of flower inhibition and increased the proportion of floral buds that set three or more fruit per bud.
Part of the flower promoting phenomena by this compound is attributed to alterations in vegetative shoot growth rates and improved light relations within the canopy, resulting in more competitive sinks for assimilates and nutrients. •
– by Bas Van den Ende and Mick Conti. Van den Ende is a tree fruit consultant in Australia’s Goulburn Valley and Conti is an orchardist in Ardmona.