Influence of Canopy Management Practices on Canopy Architecture and Reproductive Performance of Semillon and Shiraz Grapevines in a Hot Climate

Canopy management techniques can be beneficial to grapevine reproduction because they improve canopy structure and microclimate. In this study, the influence of different canopy management practices-cluster thinning, leaf removal, shoot-thinning, and light pruning-on reproductive performance was studied for the varieties Semillon and Shiraz grown under field conditions in a hot climate in South Australia. Canopy architecture, canopy light interception, and reproductive parameters for different management practices were measured. Results showed that the applied practices modified canopy architecture and influenced reproductive performance and the berry ripening process. Specifically, shoot-thinning and leaf removal decreased leaf area index and increased canopy porosity and light interception. Berry ripening was positively affected by cluster thinning and shoot-thinning, while leaf removal and light pruning delayed the process. For reproductive parameters, leaf removal had a relatively minor effect; shoot-thinning and cluster thinning reduced cluster number but showed compensation effects in other yield components, and light pruning decreased berry weight. In addition, cluster compactness was found to be significantly correlated with bunch rot (Botrytis cinerea) incidence for Semillon.