Effect of Pruning Severity and Bud Number Per Bearing Unit on Yield and Yield Components of Rainfed Grape cv. Shirazi

Suitable pruning method for grape cv. Shirazi and its response to two levels of pruning severity and bud number per bearing unit (3, 6, and 9 buds) was investigated in three years-using a factorial experiment in randomized complete block design. Analysis of variance showed that effect of pruning severity on yield, bunch weight and the number of bunch/vine was not significant, but its effect on acid content, pH, TSS%, bud productivity, berry weight and the number of berry/bunch was significant. Effect of buds number per cane on yield, bunch weight, the number of bunch/vine, acid content, pH, TSS%, bud productivity and berry weight was significant, but its effect on the number of berry/bunch was not significant. Effect of Pruning severity × bud number per bearing unit on yield, bunch weight, the number of bunch/vine, acid content and pH was significant, but its effect on TSS%, bud productivity, berry weight and the number of berry/bunch was not significant. It is concluded that cane pruning with at least 9 buds/cane and a mixed pruning method with a 6 bud cane and a two bud-spur as renewal per bearing unit is recommended to trellis and traditional training systems, respectively.