RT Journal Article SR Electronic T1 Fruitfulness and Yield Characteristics of Primary and Lateral Canes of Thompson Seedless Grapevines JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP 39 OP 43 DO 10.5344/ajev.1986.37.1.39 VO 37 IS 1 A1 L. Peter Christensen YR 1986 UL http://www.ajevonline.org/content/37/1/39.abstract AB Mature fruiting canes derived from primary or lateral shoots of Thompson Seedless grapevines were compared over three years for bud emergence and fruitfulness characteristics, and over two years for cluster development and maturation differences. The primary canes produced fewer shoots and clusters than the lateral canes, with their basal portion being the least productive. In contast, lateral canes were more fruitful near their bases. A comparison of lateral canes of first year fruiting vines with lateral canes of mature vines showed them to have similar bud emergence and fruitfulness characteristics. This explains the high fruitfulness of first year fruiting Thompson Seedless vines as the canes retained on vines of that age are derived from lateral shoots as compared to the primary canes typically retained in mature vines (2nd year of fruiting and older). Clusters on primary canes increased in size and decreased in °Brix along the canes[unknown] length. In contrast, lateral canes produced the largest and most mature clusters at both ends, proximal and distal. In spite of these cluster distribution differences between cane types, the overall means of various cluster characteristics were not different except for lower cluster °Brix in the lateral canes. Possible explanations for the cane performance differences and vineyard management implications are discussed.