TY - JOUR T1 - Effect of Minimal Pruning and Virus Inoculation on the Carbohydrate and Nitrogen Accumulation in Cabernet franc Vines JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 81 LP - 85 DO - 10.5344/ajev.1993.44.1.81 VL - 44 IS - 1 AU - E. H. Rühl AU - P. R. Clingeleffer Y1 - 1993/01/01 UR - http://www.ajevonline.org/content/44/1/81.abstract N2 - The effect on carbohydrate and nitrogen accumulation of three pruning systems and virus inoculation were studied in a split-plot experimental design. The pruning systems were spur pruning, minimal pruning of cordon trained vines (MPCT) converted from spur-pruned vines (MPCT-spur) or from cane-pruned vines (MPCT-cane). Virus treatments were uninoculated control and two sources of mild leafroll and yellow speckle from Sultana clones H4 and H5. Total carbohydrate accumulation in perennial parts and sugar accumulation in berries were identical for vines of similar size irrespective of pruning treatment, indicating that MPCT did not deplete carbohydrate reserves in roots and wood and that carbohydrate accumulation depended more on the vine size than on the pruning system. Pruning treatments, however, affected carbohydrate partitioning in the different plant parts. Spur-pruned vines accumulated less carbohydrates in old wood but more in their canes and roots than MPCT vines. Roots of spur-pruned vines were higher in starch concentrations compared to MPCT vines, which had higher levels of sugar in both old wood and roots. Amounts of nitrogen accumulated in perennial plant parts were 139 kg N/ha for spur-pruned vines and 111 and 88 kg N/ha for MPCT-spur and MPCT-cane vines, respectively. Both the inocula treatments, H4 and H5, reduced carbohydrate accumulation compared to the control. Differences between inocula indicate that the virus, graft transmitted from Sultana clone H5 is a more serious disease than that of the H4 clone. ER -