Uticaj vremena defolijacije na biološka svojstva, kvalitet grožđa i vina sorte vinove loze Cabernet Sauvignon

Abstract

Cilj ove doktorske disertacije bio je da se proceni efekat delimičnog uklanjanja listova u periodu po zametanju bobica (prečnika 3-5 mm, rana defolijacija, RD) i u vreme pojave faze šarka (kasna defolijacija, KD), na uzgojnom obliku modifikovane dvokrake kordunice sa jednom žicom u specifičnim klimatskim uslovima istočne Srbije. Defolijacijom je smanjena ukupna lisna površina čokota, a zabeleženo je i intenzivnije razviće zaperaka u tretmanu RD. U trogodišnjem eksperimentalnom periodu sa izraženim godišnjim razlikama u temperaturi, padavinama i insolaciji, RD je ispoljila jasan efekat na smanjenje mase bobice i grozda uz umanjenje prinosa, što nije postignuto sa KD. Oba tretmana defolijacije su uvećala udeo pokožice u strukturi bobice, sa izraženim uticajem RD. Manje bobice u RD zabeležile su veći odnos pokožica/mezokarp. Promene u prinosu i strukturi bobice odrazile su se i na promene u hemijskom sastavu pokožice bobice i vina. Snažan uticaj RD na smanjenje prinosa rezultirao je većim sadržajem šećera u širi i alkohola u vinu. Defolijacija je modifikovala fenolni profil pokožice bobice i vina, sa izraženim uticajem RD. Promena koncentracije ukupnih fenola, estara vinske kiseline, flavonola i antocijana u pokožici bobice i vinu su uglavnom manifestovane po principu RD>KD>K (K – kontrola, bez defolijacije), izuzev antocijana u vinu gde je samo RD beleži povećanje. Zabeležen je snažan uticaj defolijacije na flavonole. Sa izuzetkom rutina, RD je uslovila veću koncentraciju ispitivanih flavonola u pokožici bobice, dok je u vinu najveći uticaj ispoljen na povećanje sadržaja miricetina i kvercetina. Od ispitivanih antocijana najzastupljeniji u pokožici i vinu bio je malvidin-3-glukozid. Njegova koncentracija je povećana primenom RD, ali ne i KD, što je isto zabeleženo i kod katehina. Efekat KD na ispitivane parametre u ogledu je uglavnom bio manji ili je izostao. Utvrđen je i statistički značajan uticaj godine. Vina dobijena tretmanima defolijacije su bolje ocenjena senzornom analizom, dok su kontrolna vina postigla najniže ocene tokom eksperimentalnog perioda.

The aim of this doctoral dissertation was to assess the effect of partial leaf removal in the period after berry set (diameter of berries 3-5 mm, early defoliation, ED) and at the beginning of veraison (late defoliation, LD), on a modified single wire bilateral cordon system in specific climatic conditions of Eastern Serbia. Defoliation reduced the total leaf area per vine, but more intensive development of lateral shoots was noted in the ED treatment. In a three-year field experiment with pronounced interannual variability of temperature, precipitation and insolation, ED showed a clear effect on reducing the berry mass and cluster weight also reducing the yield, which was not achieved with LD. Both defoliation treatments increased skin proportion in the berry structure, with a pronounced influence of ED. Smaller berries in ED also recorded a higher skin/mesocarp ratio. Changes in the yield and berry structure reflected on chemical composition of the grape berry skin and wine. Strong impact that ED had on the yield reduction resulted in the higher sugar content in grape juice and alcohol in wine. Defoliation modified the phenolic profile of berry skin and wine, with a pronounced effect of ED. Changes in the concentration of total phenols, tartaric acid esters, flavonols and anthocyanins in berry skin and wine are mainly manifested by the pattern ED>LD>C (C – undefoliated control), with the exception for anthocyanins in wine where only ED records an increase. A strong effect of defoliation on flavonols was noted. With the exception of rutin, ED caused a higher concentration of flavonols in the berry skin, while in wine the greatest influence was shown on the increase of myricetin and quercetin content. Out of all the investigated monomeric anthocyanins, malvidin-3-glucoside is the most abundant, both in berry skin and wine. Its concentration was increased by the ED, but not LD, which was also observed with catechins. The effect of LD on the examined parameters in the experiment was mainly lesser or absent. A statistically significant impact of the year was also determined. Wines obtained from defoliation treatments were better scored by the sensory analysis, while the control wines score the lowest points throughout the experimental period. Keywords: Scientific field: