Early canopy development and production precocity in new orchard system designs for cherry

Existing sweet cherry orchard layouts intercept approximately 60 to 65% of incoming solar radiation, and yields ha^-1 are lower than in many other tree crops. Light penetration into the centre of these canopies can be less than 5%, reducing fruit and bud quality. New orchard system designs are being developed that aim to increase productivity by increasing light interception to ~85%, and by improving precocity, harvest index, light distribution and associated fruit quality within the canopies. Bi-axis nursery trees of three cultivars of cherry were planted in a replicated trial in spring 2014 at a spacing of 3 m between trees in rows spaced either 1.5 or 2 m apart. Each axis was trained in opposing directions along the row as an inclined cordon, from which up to six upright shoots per cordon were encouraged to develop, and shoots were trained either vertically or as a narrow vee. By the end of the second season of growth in the orchard, the upright shoot position closest to the cordon base had a higher frequency of development of upright shoots than any of the other five positions. Frequency of upright shoots in this proximal position were 56, 82 and 87% for ‘Lapins’, ‘Sweetheart’ and ‘Staccato’, respectively. Upright shoots in this position were also the longest, with means ranging from 128 cm for ‘Lapins’ to 173 cm for ‘Staccato’. For ‘Lapins’, 23% of the trees developed upright shoots in the most distal position on the cordons in the first season, whereas almost no shoots developed in this position for ‘Sweetheart’ and ‘Staccato’ trees. However, by the end of the second season, more trees of ‘Sweetheart’ and ‘Staccato’ had developed upright shoots in the distal position than ‘Lapins’. Estimated yields in the second season after planting were between 0.3 and 0.8 t ha^-1, depending on cultivar and between-row spacing. Yield estimates increased to between 1.1 and 2.1 t ha^-1 when losses to bird damage were accounted for.