Canopy architecture impact on peach tree physiology, vigor diffusion, productivity and fruit quality

• Training systems horticulturally manipulate tree vigor. • Planting density strongly dictates orchard productivity potentials. • Multi-leader architectures diffuse vigor and enhance fruit quality. • Single leader systems prioritize uniform light distribution, but retain high vigor. • MDP systems balance fruit quality and establishment costs with higher labor needs. Horticultural manipulation of canopy architecture and orchard design helps enhance peach orchard productivity and fruit quality potentials. Training systems horticulturally manipulate vigor and the canopy architecture to optimize light interception, distribution and penetration for improved yields and fruit quality. The ideal selection of training system and planting density varies based on land availability, upfront costs, pedoclimatic conditions, rootstocks and grower goals. This long-term study sought to evaluate six different training systems, ranging from low- to high-density plantings (HDP), in cultivar ‘Redhaven,’ for their influence on tree physiology, vigor diffusion, productivity and fruit quality development. The six training systems assessed were of (a) high density: Tall Spindle Axis (TSA, one leader), Bi-Axis (BA, two leaders in-row) and KAC-V (Kearney Agricultural Center -V, two leaders perpendicular); (b) medium density: Quad-V (four leaders) and Hex-V (six leaders); and (c) low density: Open Vase (three leaders and 6 sub-leaders). Crop load and fruit maturity were adjusted for uniformity across cropping seasons to eliminate confounding variables in assessments. Tree size and yield per tree were closely related to planting density, with lower-density plantings generating bigger canopies and fruiting potentials, although there is a delay in production due to scaffold development. Production on a per unit land area increased with planting density and reached commercial yields earlier. Light was more uniformly distributed in planar canopies, while complex canopies with multiple upright scaffolds had reduced leader cross-sectional area to trunk cross-sectional area ratios (i.e., vigor diffusion), which related to increased fruit weight and dry matter content in these systems. In this study, HDP systems created uniform canopies that were simpler to manage and increased per hectare production, while MDP systems had increased vigor diffusion, which increased fruit size and dry matter content.