BUNCH LOAD AS A FACTOR ON THE QUALITY OF THE GRAPEVINE VARIETIES Ã¢â ¬Ë RIBIERâ⠬⠢ AND Ã¢â ¬Ë ITALIAâ⠬⠢

Abstract

The application of ampelotechnical measures in table grape production profoundly affects grape yield and quality. This study aims to assess the influence of the ampelotechnical practice of bunch thinning on the yield and quality of Ribier and Muscat Italia grape varieties. The research was conducted over three consecutive years on production plantations of Ribier and Muscat Italia varieties grown on pergola training system with a planting distance of 2.5 x 2.5 m. The plantations are in full fertility, aged between 12-15 years, located in the Gevgelija-Valandovo vineyard, renowned as one of the most suitable sites for cultivating table grapes in the Republic of Macedonia. Three different bunch thinning variants were applied in both varieties: V1 (thinning to 4 bunches/m2 ), V2 (thinning to 5 bunches/m2 ), and V3 (thinning to 6 bunches/m2 ). These were compared with the standard variant where no bunch thinning was performed. Our research findings demonstrate that the applied ampelotechnical measure significantly impacts the average bunch and berry mass, transportability, must chemical composition, packed grape quantity, and organoleptic evaluation of the grapes. The average bunch mass of the Ribier variety ranges from 381,3 g in the standard (St) variant to 445,7 g in the V1 variant. Similarly, in the Italia variety, the bunch mass fluctuates between 607.3 g (St variant) and 703,0 g in the V1 variant, while the berry mass ranges from 7,5 g (St) to 8,5 g (V1). Moreover, the packed grape quantities range from 1,9 kg/m2 in the standard variant to 2,31 kg/m2 in the V2 variant for the Ribier variety, whereas for the Italia variety, the lowest amount of packed grapes was recorded in the V1 variant (2,65 kg/m2 ), and the highest in the V3 variant (3,27 kg/m2 ). Notably, the organoleptic evaluation of the grapes was influenced by bunch thinning. The V1 and V2 variants in both varieties received better ratings compared to the other variants, with the Ribier variety rated as excellent quality and the Italia variety as extra quality.