Effects of shoot girdling on carbon partitioning and bud fertility in Vitis vinifera cv. Malbec

CARRILLO N.; PICCOLI P.; GUARDABRAZO M.S.; BERLI

Santa Fé

Congreso; XXXIII Reunión Argentina de Fisiología Vegetal (RAFV); 2021

Sociedad Argentina de Fisiología Vegetal (SAFV)

Malbec is the most cultivated vine variety in Argentina. Although different selection processes have been carried out for many years and there are currently improved clones, many commercial Malbec vineyards present a marked instability of their productive potential. This is due to shatter, inflorescence necrosis, abscission of fruits and low fertility. It is known that carbohydrates are the major determinant of fruit set in grapes. Also, inflorescence or bunchstem necrosis is associated with a low supply of carbohydrates. Previous studies have demonstrated that redistribution of carbohydrates within the shoot could be performed by removing a portion of phloem tissue through an annular incision. The objective of this research was to evaluate the effect of girdling shoots in carbon partitioning and bud fertility. Three girdling treatments were applied to shoots at the beginning of bloom: a control without girdling; a girdle at the base of the shoot; and a girdle above the last cluster. The results showed that the girdling treatments increased node diameter, shoot fruitfulness and inflorescence dry weight. Total dry matter was similar for control and base girdled shoots, however, top girdled shoots reduced total dry matter significantly. A girdled at the base of the shoots altered the partitioning of carbon within the shoot, favoring the accumulation of carbohydrates towards clusters at expense of lateral shoots.