EFFECT OF GIRDLING THE CANES OF THE 'KHUSAYNE BELIY' GRAPE CULTIVAR (Vitis vinifera L.) AT DIFFERENT TIMES ON THE STRUCTURE AND QUALITY OF GRAPE BERRIES

ISSN: 2582-4686 SJIF 2021-3.261,SJIF 2022-2.889, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-4 1284 EFFECT OF GIRDLING THE CANES OF THE ‘KHUSAYNE BELIY’ GRAPE CULTIVAR (Vitis vinifera L.) AT DIFFERENT TIMES ON THE STRUCTURE AND QUALITY OF GRAPE BERRIES F.A. Boyto‘rayeva PhD student of Tashkent State Agrarian University Abstract: This study investigated the effects of girdling at different growth stages on the cluster structure and fruit quality of the “Khusayne beliy” grape variety. Girdling before flowering increased cluster weight, berry size, and diameter, while girdling after flowering resulted in slightly higher sugar content and lower acidity. Overall, girdling before flowering had the most positive impact on yield quality and accelerated ripening by 2–3 days. Keywords: Girdling, grape quality, Khusayne beliy, berry size, sugar content, ripening Introduction. Removing a ring-shaped portion, approximately 3–5 mm wide, of bark and part of the phloem from the cane or trunk is called girdling. This method has been widely used for many years to increase bunch size, sugar accumulation, and color intensity of grape clusters [4]. Girdling stops the downward movement of organic nutrients and improves the nourishment of flowers and berries. It reduces flower drop, enhances cluster growth, increases berry weight, and accelerates ripening. The timing of girdling may correspond to several phenological phases: before flowering, during berries growth, or at the beginning of berry ripening. Girdling has the greatest effect on seedless and raisin-type cultivars, which naturally produce loose clusters. However, continuous girdling reduces the amount of plastic substances reaching the roots, weakens the vines, and shortens their lifespan [7]. Studies on the effect of girdling on grape aroma composition are limited. A recent study on the “Riesling” variety reported that girdling arms after the beginning of ripening significantly increased monoterpenoid accumulation while reducing esters and higher alcohols in the berries [3]. Consequently, wines produced from such grapes showed notable alterations in the levels and profiles of several compound classes, potentially causing significant changes in wine aroma and taste. However, when grapes total soluble solid reached 18 °Brix, girdling caused minimal changes in amino acid concentrations and volatile wine constituents. These findings indicate that once berries reach typical sugar concentration, further sugar import is prevented even under invasive treatments like girdling, resulting in minimal influence on wine volatile composition [2]. Materials and Methods. The experiments were carried out in the vineyard fields of “Gulbog Burkhon” farm, located in the Parkent district of Tashkent region. The experiments are conducted in accordance with the requirements of the methodological manual authored by X.Ch. Boriyev et al. “Mevali va rezavor mevali o‘simliklar bilan tajribalar o‘tkazishda hisoblar va fenologik kuzatuvlar metodikasi” (2014) [1], V.F. Moiseychenko “Методика учетов и наблюдений в опытах с плодовыми и ягодными культурами” (1987) [8], and A.J. Winkler’s “General Viticulture” [6]. Girdling was performed on the canes below the inflorescence. A grafting knife or a special girdling tool was used to girdling. 3–5 mm wide of bark of every cane was removed 7-10 days before and after flowering period. The harvest was collected in the second decade of August, when the grapes reached technical ripeness. ISSN: 2582-4686 SJIF 2021-3.261,SJIF 2022-2.889, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-4 1285 Results and Discussion. The timing of girdling varied depending on the research purpose: at the beginning of flowering – to improve fruit set; during berry growth – to increase cluster size; at the beginning of ripening – to accelerate ripening. In small-berried cultivars, girdling is usually carried out before flowering. Table 1 presents the effects of girdling before and after flowering on the structure and composition of grape clusters of the cv. “Kusayne beliy”. Table 1. Effect of Girdling Before and After Flowering on the Structure and Composition of Grape Clusters of the 'Khusayne Beliy' Variety Types of Girdling treatment Total cluster weight, g Total number of berries a cluster, piece Total berry weight a cluster, g Weight berry, g Berry diameter mm Sugar content, % Total acidity, g/l Control (nongirdled) 450,10 67,27 434,94 6,52 15,72 17,74 3,01 Girdling before flowering 481,16 64,64 464,96 7,22 16,80 17,92 2,98 Girdling after flowering 461,24 64,95 445,10 6,96 16,02 18,04 2,94 As seen in Table 1, the lowest average cluster weight was observed in the control variant (450.1 g), whereas the highest was in the variant girdled before flowering (481.2 g). However, the highest number of berries per cluster was recorded in the control (67.3 berries), while the lowest value was in the variant girdled before flowering (64.6 berries). The heaviest berry weight was also recorded in the variant girdled before flowering (7.22 g), which was 0.68 g higher than the control. Similarly, berry diameter reached its highest value (16.8 mm) in the same variant. The highest sugar content was observed in the variant girdled after flowering (18.04%), which was 0.3% higher than the control. Regarding total acidity, opposite trends were recorded: the highest acidity was in the control (3.01 g/l), while the lowest value was in the variant girdled after flowering period (2.94 g/l). In commercial vineyards, girdling is commonly applied by removing a 3–5 mm ring of bark around certain parts of the vine. Although it can be applied to trunks, canes, or shoots, girdling trunks is not recommended due to difficulty, expense, and slow wound healing. For cultivars with fruiting on oneyear-old canes, girdling the trunk or individual canes is may more efficient and economical. Girdling has been widely used to improve fruit set and increase cluster size, but its ability to accelerate ripening remains controversial. In the “Black Corinth” and “Thompson Seedless” cultivars, the girdled area healed quickly and had no significant effect on ripening [5]. Conclusion. Girdling has a positive effect on the growth and development of grape clusters and accelerates ripening. Generally, it is applied during cluster formation to increase berry size or during ripening to enhance color development and stimulate maturation. Increased cluster size is the result of improved carbohydrate accumulation above the girdled area, as girdling prevents downward sugar ISSN: 2582-4686 SJIF 2021-3.261,SJIF 2022-2.889, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-4 1286 transport to the roots. Based on the results of this experiment, girdling the canes before flowering has a more pronounced positive effect on the quality of grape yield compared to girdling after flowering, and it accelerates ripening by 2–3 days. References 1. Boriyev X.Ch. et al. Mevali va rezavor mevali o‘simliklar bilan tajribalar o‘tkazishda hisoblar va fenologik kuzatuvlar metodikasi. - Tashkent – 2014. – p. 6-20. 2. Böttcher C., Boss P.K., Harvey K.E., Burbidge C.A., Davies C. Peduncle-girdling of Shiraz (Vitis vinifera L.) bunches and sugar concentration at the time of girdling affect wine volatile compounds. / Australian Journal of Grape and Wine Research, 2018. – v. 24(2). P. 206–218. doi.org/10.1111/ajgw.12319 3. Böttcher C. et al. Post-veraison restriction of phloem import into Riesling (Vitis vinifera L.) berries induces transient and stable changes to fermentation-derived and varietal wine volatiles. / Aust. J. Grape Wine Res., 2019. – v. 25. – P. 286–292. 4. Herrera E. Improving size and quality of seedless grape. - New Mexico State University, Cooperative Extension service, 2002. Guide H-311. P.1-4. 5. Jacob H.E. Girdling grape vines. California Agricultural Extension Service Circular 56. September, 1931. P. 3-18. 6. Winkler A. J. et al. General viticulture. California: University of California, 1974. 710 p. 7. Верновского Э.А. Технология возделивания и использование винограда. Москва, Агропромиздат – 1990. С. 172. 8. Мойсейченко В.Ф. Методика учетов и наблюдений в опытах с плодовыми и ягодными культурами. Киев – 1987. С. 69.