Abstract
To understand the influence of spur quality on subsequent fruiting, 9-year old 'Alachua', 'Carlos', 'Nesbitt', and 'Noble', muscadine grapevines growing at the Viticulture Center, Florida A&M University, were used for this investigation. For each cultivar, 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 by 134.5%, 137.2%, 56.0% and 173.4% for 'Alachua', 'Carlos', 'Nesbitt', and 'Noble', respectively. Correlation between spur diameter and shoot/spur (0.01 ns-0.2***), cluster/ shoot (0.01-0.25***), fruit number/cluster (0.02ns-0.32***), and fruit size (0.01 ns-0.33***) differed among the cultivars. There was no significant influence of spur diameter on fruit soluble solids content (R2 = 0.01 ns-0.04 ns).
