Applied GA5, GA4 and GA4/7 increase berry number per bunch, yield and grape quality for winemaking in Vitis vinifera L. cv. Malbec

BERLI F.; ALONSO R.; PHARIS R.P.; BOTTINI R.

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2022 vol. 102 p. 2950 - 2959

0022-5142

BACKGROUND: The gibberellins (GAs) GA5 (inhibitor of GA3-oxidase), GA4 (biologically active), GA4/7 (commercially available mixture) Prohexadione-Ca (ProCa, inhibitor of dioxygenases that render GAs bioactive, negative control) and GA3 (positive control), were applied to bunches of Vitis vinifera cv. Malbec. Different techniques, doses and timings were used in a three-years field experiments. In year 1, GA5, ProCa and GA3 were applied at 35, 20 and 0 days before veraison (DBV) by dipping bunches three times. In year 2, single applications of GA5 and GA3, also by immersion, were tested at 60, 45 and 30 DBV. In year 3, applications at 60 and 30 DBV of GA5, GA4 and a mixture of GA4/7 were evaluated, by dipping or spraying the bunches.RESULTS: Vegetative growth, berry weight and sugar content were unaffected by treatments. ProCa did not affect the yield respect to water control, although reduced the levels of phenolics in berry skins, an undesirable effect for winemaking. GA5 in a dose range of 5 to 50 mg/L, raised berries number thereby augmenting bunch weight and skin phenolics at harvest, so increasing berries quality for winemaking. GA4 and GA4/7 produced similar benefits to GA5, with similar doses.CONCLUSION: The applications of GA5, GA4 and GA4/7 to developing grape berry bunches, in a range of concentrations and by dipping or spraying, increased berry numbers per bunch at harvest. The method can be a viticultural practice to improve the production and quality of wine grapes.