Evaluation of the Carry-Over Effect of the "Crop-Forcing" Technique and Water Deficit in Grapevine 'Tempranillo'

"Crop-forcing" is an effective technique to delay grape maturation to a period of lower temperatures, and in this way, improve grape quality. Because of the aggressiveness of this technique (removal of leaves and fruit to reinitiate a second vegetative cycle), it may affect the level of reserves and could provoke progressive vine exhaustion. The aim of the present work is to evaluate the short- and medium-term evolution of carbohydrate reserves in different plant organs and the effect of "crop-forcing" under different irrigation regimes on seasonal biomass production and its distribution. The study was carried out over a four years period (2017-2020), applying "crop-forcing" in three consecutive years (2017-2019) to the same vines on two different dates and using two irrigation strategies. The application of "crop-forcing" did not decrease root reserve levels in either the year of application or the following year, but did modify starch and soluble sugar levels in shoots and leaves in some moments of the vegetative cycle during the years of "crop-forcing" application. Total biomass production in terms of grams per vine was lower in the "crop-forcing" treatments and continued to be so when "crop-forcing" was no longer applied. The percentage of biomass in vegetative organs increased at the expense of productive organs.