Scoring increases carbohydrate availability and berry size in seedless grape ‘Emperatriz’

In grapes, seedlessness is an important quality attribute for fresh consumption. There are seedless cultivars but their berries are often very small. A cane-scoring technique proved effective in increasing average berry size of ‘Emperatriz’ seedless grape by 16% in a 4-year experiment, and increased bunch weight by 8.2–28.6%, compared with unscored bunches, depending on the year, but had no effect in ‘Aledo’ seeded grape. This effect was due to: (1) a significantly higher daily berry growth rate in scored vines at 30–50 d after scoring; (2) an advance in time of accumulation of reducing sugars, particularly glucose; (3) a reduction of berry water potential of seedless ‘Emperatriz’ of similar values to those of seeded ‘Aledo’. Cane scoring showed no negative effect on the number of harvested bunches per vine the year following the scoring year, both in ‘Emperatriz’ and ‘Aledo’ cultivars.