Influence of spur quality/density on productivity and fruit quality in muscadine grapes

• Author(s): Lu, Jiang; Ren, Zhongbo;
• Abstract: To understand the influence of spur quality to subsequent fruiting, 9-year old muscadine vines of Alachua, Carlos, Nesbitt and Noble, growing in the Viticulture Center, Florida A&M Univ., were used for this investigation. Each cultivar consisted of five vines and twenty spurs from each vine were randomly selected. Spur diameters were variable among these cultivars, with an average of 38.3 mm, 46.2 mm, 41.2 mm, and 43.4 mm for Alachua, Carlos, Nesbitt and Noble, respectively. Spur diameters were highly correlated with yield among all the cultivars investigated (R2 = 0.07**-0.28***). For example, when spur diameter increased from 20 mm to 60 mm, production increased to 134.5%, 137.2%, 56.0% and 173.4% for Alachua, Carlos, Nesbitt and Noble, respectively. Correlation between spur diameter and shoot/spur (0.01ns-0.2***), cluster/shoot (0.01-0.25***), fruit number/cluster (0.02ns-0.32***) and fruit size (0.01ns-0.33***) differed among the cultivars. No significant influence was found of spur diameter to fruit soluble solids content (SSC, R2 = 0.01ns - 0.04ns). Correlation between spur density and yield/fruit quality was also estimated for the same four muscadine cultivars. Results from this study indicated that total fruit clusters per vine were linear to the total number of spurs. Yields were proportionally correlated to spur density, and correlation between yield and spur density was also cultivar dependent. Total titration acid content varied with cultivars, but not with the density of spurs. These data indicated that a large number of spurs or clusters are critical for high yield, but higher spur density may jeopardize the fruit qualities.
• Publication Date: Jun 2001
• Journal: Hortscience