Canopy Modification Influences Growth, Yield, Quality, and Powdery Mildew Incidence in Tas-A-Ganesh Grapevine

Abstract

ABSTRACT A field trial was conducted to study effect of different canopy modifications on growth, yield, quality, and disease incidence in Tas-A-Ganesh grapevine grafted onto Dogridge rootstock. Ten-years-old vines trained to extended Y training system with three types of canopy modifications [Single Cordon Horizontal (SCH), Double Cordon Horizontal (DCH), and Four Cordon Horizontal (FCH)] were selected for study. The vines had horizontally placed cordon with vertically positioned shoot on the cordon. Results of different canopy modification demonstrated that, among the vegetative growth parameters studied, pruning weight and shoot length was significantly higher in DCH. Days to bud sprout and cane diameter had no significant influence of any of the canopy modifications studied. Significant differences were observed for leaf area index, photosynthesis rate, stomatal conductance, and transpiration rate. The vines trained to DCH had higher rate of photosynthesis. Yield per vine and number of bunches per vine was higher in FCH. Maximum total soluble solids (TSS) was recorded in SCH. Total acidity was increased with increase in cordons from SCH to FCH. Lower concentration of total acids was recorded in SCH (0.56%). We observed that as bunch load increased, TSS was reduced while total acidity was increased. The disease assessment data from different canopy modifications revealed that powdery mildew incidence was significantly increased from SCH to FCH with increase in canopy density. The results supported with concentration of lower phenols in powdery mildew-infected canopy (FCH). The results revealed that the canopy with DCH canopy modification performed better for growth and yield and reduced disease incidence.