Influence of defoliation on carbohydrate reserves of young grapevines in the nursery

Abstract

Summary The influence of partial and total defoliation of grafted vines, performed during the period of intensive growth (July, August, September), on the accumulation of carbohydrates in roots, canes and rootstock was studied in Vitis vinifera L. ssp. sativa cv. 'Riesling', clone 239 grafted on the rootstock 'SO4', clone 31. Total defoliation in July resulted in the lowest percentage yield of grafted vines and the lowest weight of roots. In canes, total defoliation caused the lowest total carbohydrate content (TCC) in September, whereas in roots, the lowest TCC was established in August and September, in particular, owing to the reduced starch content. The most significant difference in the TCC between partial and total defoliation was observed in August.