Standardization of canopy management practices for table grape production under subtropical climate

Abstract:

Grape growers in the Western Cape of South Africa have trained vines on the head system since the early Cape viticulture trials of the 1920s, a choice that suited small plots but no longer matches modern commercial table-grape production. This research compared five canopy training systems—head training (local standard), four-arm Kniffin, single curtain, Geneva Double Curtain (GDC), and Y-trellis—on Thompson Seedless grape at the Stellenbosch research vineyard across three consecutive seasons (2020-21 to 2022-23). Vegetative parameters, light interception, yield, berry quality, and labour hours were tracked season-wise. GDC recorded the highest cumulative yield at 63.1 t ha⁻¹ over three seasons, followed by Y-trellis (54.7), single curtain (50.7), Kniffin (38.7), and head training (27.1). Photosynthetically active radiation interception peaked at 82.4% under GDC and dropped to 47.6% under head training. Berry TSS varied narrowly across systems (18.4-19.8 °Brix). Labour hours per hectare per season were highest in GDC (348 h) and lowest in head training (214 h), but per-tonne labour cost was lowest in GDC at R 1,580. GDC is recommended for commercial orchards where trellis investment can be justified, while Y-trellis suits medium holdings looking for a balance between productivity and simplicity.