S16 - Session O1 - Pomological performance of a 2-dimensional planar cordon apple orchard

Authors: Ben van Hooijdonk *, Jess Byrne, Tessa Leitch, Ken Breen, Hassan Saei, Daya Dayatilake, Stuart Tustin, Adam Friend

New Zealand apple orchards are planted with wide inter-rows (3+ m) to facilitate machinery access. Consequently, mature apple orchards achieve a maximum fractional light interception of only 60%, limiting yields annually to ~100 t/ha. Therefore, we tested new prototype apple orchards comprising narrow inter-rows and 2-dimensional tree arrays, purposely designed to increase orchard light interception and yield. In 2014, bi-axis 'Royal Gala' and 'Scifresh' trees on 'Malling 9' rootstock were planted at 3 m between trees within the tree rows, with inter-row spacings of 1.5 m (2222 trees/ha) or 2 m (1667 trees/ha). Each inter-row spacing incorporated 2-dimensional planar cordon trees trained with upright fruiting branches oriented either vertically or in a narrow vee. Using 'Royal Gala' as an example, 7-year-old experimental orchards planted at the 1.5-m and 2-m inter-row spacings achieved a fractional light interception of 92% and 85%, respectively, with corresponding gross yields of 180 t/ha and 139 t/ha. Comparatively, the upper quartile of high-performing commercial New Zealand 'Royal Gala' orchards produce an average gross yield of ~75 t/ha at the same age. In addition to yield improvement, quality and uniformity (colour, size, dry matter concentration) of fruit from the planar cordon orchard systems were often quantitatively superior. We discuss the pomological performance of a planar cordon orchard across eight years of study, and describe mature tree architecture, fruit set behaviour and relationships between within-canopy light flux and fruit dry matter concentration.