Sultana fruitfulness and yield as influenced by season, rootstock and trellis type

• Autores: Karl J. Sommer, Peter R. Clingeleffer, Muhammad T. Islam
• Localización: Australian journal of grape and wine research, ISSN 1322-7130, Vol. 7, Nº 1, 2001, págs. 19-26
• Idioma: inglés
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• Resumen

  • Field-grown vines (Vitis vinifera L. cv. Sultana) were examined for their fruitfulness and yield performance over four growing seasons. Vines were either grafted to Ramsey rootstock (Vitis champini) or were grown on their own roots. Four commercially applied trellising systems were investigated, namely, a T-trellis, a Shaw trellis with a double cordon, a Shaw trellis with a single cordon and a Shaw swing-arm trellis. Fruiting potential was assessed shortly after budburst using the Merbein bunch count method. Bunches on vines that had been counted in springtime were again counted at harvest, and vine yield recorded. During the four years of the experiment fruitfulness was strongly influenced by growing season. Fruitfulness per node along the cane followed a well-established trend. Bud fruitfulness was close to zero in basal nodes but increased steeply thereafter reaching a maximum between nodes 8 and 10. Fruitfulness then decreased steadily. Grafted vines were always less fruitful than own-rooted vines, and this difference was amplified for all trellis designs in years when fruitfulness was low. At the time of pruning, more canes were retained on grafted than own-rooted vines in accordance with the greater vigour of grafted vines. This pruning strategy resulted in a larger number of bunches on grafted relative to ungrafted vines.