Training System Effects on Sunlight Penetration, Canopy Structure, Yield, and Fruit Characteristics of ‘Frontenac’ Grapevine (<i>Vitis</i>spp.)

Abstract

Trellis or training systems influence many aspects of grapevine growth and production. This study investigated the effects of four trellis styles (Geneva double curtain, high cordon, Smart-Dyson, and vertical shoot positioned) on the fruit-zone light environment, fruit chemical composition, and yield of 'Frontenac' grapevines (Vitis spp.) grown on a fertile site near Crete, Nebraska over two growing seasons. Photosynthetically active radiation was measured above the canopy and within the fruiting zone at berry set, veraison, and harvest. At all sampling dates in 2008, vines grown on Geneva double curtain and high cordon had higher mid-day transmittances than vines grown on Smart-Dyson and vertical shoot positioned. In 2009, transmittance relationships among training systems were similar. In both years, leaf layer number was lower for Geneva double curtain and high cordon than for Smart-Dyson and vertical shoot positioned. In 2008, Geneva double curtain vines had higher fruit yield than vertical shoot positioned, Smart-Dyson, and high cordon. In 2009, Geneva double curtain yielded more than vertical shoot positioned and high cordon. In 2008, Geneva double curtain had higher pH and °Brix than other trellises; titratable acidity was lower in Geneva double curtain and high cordon than in Smart-Dyson and vertical shoot positioned. In 2009, fruit composition results were not related to transmittance. We propose Geneva double curtain training as a viable choice for Midwestern growers.