Vpliv terminov rezi na dozorevanje in kakovost grozdja žlahtne vinske trte 'Merlot'

Štrancar, Martin (author), Rusjan, Denis (mentor)

V raziskavi za magistrsko delo smo želeli ugotoviti, kako pozna zimska rez (PZR) in dvojno namensko zorenje (DNZ) vplivata na fenologijo vinske trte in kakovost grozdja. Poskus smo izvedli leta 2024 na sorti 'Merlot', pri kateri smo vključili štiri obravnavanja, in sicer pozno zimsko rez na dan 22. 4. (PZR-1), pozno zimsko rez na dan 1. 5. (PZR-2), dvojno namensko zorenje (DNZ) in kontrolo (K). Med rastno dobo smo spremljali fenologijo trt po BBCH-sistemu. Po obravnavanjih in ob trgatvi smo prešteli število vseh grozdov na trto. Jagode smo med zorenjem vzorčili dvakrat in stehtali maso 100 jagod, izračunali CIRG-indeks, izmerili vsebnosti topne suhe snovi, posameznih sladkorjev, skupnih in posameznih kislin, pH, vsebnost skupnih in posameznih fenolov v jagodah ter slednje tudi v pečkah. Ugotovili smo, da PZR zamakne fenologijo trte za povprečno 7–10 dni, zmanjša število grozdov (PZR-2 ima približno štiri grozde manj na trto) in maso 100 jagod (samo pri prvem vzorčenju za 20–25 g). Pri grozdju trt PZR-1 smo izmerili značilno večjo (21,7 ± 0,18 ºBrix) vsebnost topne suhe snovi kot pri PZR-2 (20,9 ± 0,18 ºBrix), medtem ko je vsebnost skupnih kislin pri grozdju PZR-1 (7,32 ± 0,19 g/l) in PZR-2 (7,33 ± 0,19 g/l) značilno večja le pri prvem vzorčenju od grozdja kontrole (5,49 ± 0,19 g/l). Prav tako je imelo grozdje PZR-1 in PZR-2 v prvem terminu nižji pH od K, pri drugem pa grozdje PZR-2 celo višjega. Vsebnost skupnih fenolov v pečkah je značilno večja le pri PZR-2, medtem ko se vsebnosti fenolnih spojin v kožicah jagode med obravnavanji niso razlikovale. DNZ ima vpliv le na manjšo maso 100 jagod (za 20–25 g) in večjo vsebnost topne suhe snovi za od 2 do 3 ºBrix. PZR priporočamo kot ukrep za zakasnitev poteka fenofaz in ohranjanje svežine v vinu, DNZ pa za koncentracijo topne suhe snovi in ohranjanje vsebnosti skupnih kislin.

• Language: Slovenian
• Keywords: vinska trta, podnebne spremembe, pozna zimska rez, fenologija, dvojno namensko zorenje, grozdje, kakovost
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Year: 2026
• PID: 20.500.12556/RUL-185453
• COBISS.SI-ID: 287609603
• Publication date in RUL: 06.08.2026

Secondary language

• Language: English
• Title: The impact of pruning times on the ripening and quality of grapevine 'Merlot'

Abstract

In this master’s thesis study, we aimed to determine how late winter pruning (LWP) and Double Maturation Raisonné (DMR) affect grapevine phenology and grape quality. The experiment was conducted in 2024 on the 'Merlot' variety, in which we included four treatments: late winter pruning on April 22 (LWP-1), late winter pruning on May 1 (LWP-2), Double Maturation Raisonné (DMR), and a control (C). During the growing season, we monitored vine phenology according to the BBCH scale for each treatment, and at harvest, the total number of clusters per vine was recorded. Berries were sampled twice during ripening; for each sample, the weight of 100 berries was measured, the CIRG-index was calculated, and the content of total soluble solids, individual sugars, total and individual acids, pH, as well as total and individual phenolic compounds in berries and seeds were measured. The results showed that LWP delayed vine phenology by an average of 7–10 days, reduced the number of clusters (LWP-2 had approximately four fewer clusters per vine), and decreased the weight of 100 berries (only at the first sampling, by 20–25 g). Grapes from LWP-1 vines had a significantly higher total soluble solids content (21.7±0.18 °Brix) compared to LWP-2 (20.9±0.18 °Brix). The total acidity in grapes from LWP-1 (7.32±0.19 g/L) and LWP-2 (7.33±0.19 g/L) was significantly higher than in the control (5.49 ± 0.19 g/L), but only at the first sampling. Similarly, grapes from LWP-1 and LWP-2 had lower pH values than the control at the first sampling, while at the second sampling, LWP-2 grapes exhibited an even higher pH than the control. The content of total phenols in seeds was significantly higher only in LWP-2, whereas phenolic compounds in berry skins did not differ significantly between treatments. DMR affected only lower weight of 100 berries (by 20–25 g) and higher total soluble solids by 2 to 3 °Brix. LWP is recommended as a practice for delaying phenological development and preserving freshness in wine, while DMR is recommended for increasing total soluble solids concentration and maintaining total acidity.

• Keywords: grapevine, climate change, late winter pruning, double maturation raisonnée, grape, quality, phenology