Kevad- ja sügiskatete mõju viinapuude (Vitis) saagi tehnoloogilisele küpsusele
Laen...
Kuupäev
2019
Kättesaadavus
5.09.2019
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Viinamarjade küpsus saagikoristusel määrab veini stiili ning kvaliteedi. Tehnoloogilist
küpsust hinnatakse marjamahla kuivaine, orgaaniliste hapete ja pH sisalduse põhjal.
Varasem katsetöö Eestis on näidanud, et jaheda suve tingimustes on marjadel probleeme
liiga kõrge happesuse ning madala suhkrusisaldusega. Kasvatustehnoloogiliste võtetega
on võimalik mõjutada marjade biokeemilist koostist. 2017. aasta suvel uuriti Eesti
Maaülikoolis viljatsooni katmist küpsemise faasis, kuid mitmed võtmetähtsusega
protsessid leiavad marjas aset arengu algfaasis. Sellest tingituna püstitati hüpotees, et
kevad- ja sügiskatetega saab mõjutada viinamarjade küpsemist ja tehnoloogilise küpsuse
parameetreid. Uurimistöö eesmärk oli hinnata katete mõju hübriidsortide ‘Zilga’ ja
‘Hasanski Sladki’ marjade tehnoloogilise küpsuse parameetritele: mahla kuivaine,
orgaaniliste hapete ja pH sisaldusele.
Katse viidi läbi 2018. aastal avamaa tingimustes Eesti Maaülikooli Rõhu katsejaamas
Tartu maakonnas. Katsesortideks olid hübriidsordid ‘Hasanski Sladki’ ja ‘Zilga’.
Kattematerjalidena kasutati polüetüleenkilet, varjutuskangast ja katteloori. Kevadkatted
paigaldati mõlemale sordile perioodiks 16.05–11.06. Sordil ‘Hasanski Sladki’ olid
kontrollvariandiks katmata viinapuud, sordil ‘Zilga’ kontrollvariant puudus. Sügiskatteid
kasutati ainult sordil ‘Hasasnski Sladki’ ja katteid kasutati viinapuudel, mis olid kevadel
katmata. Sügiskatted olid kasutusel perioodil 16.08–19.09. Mahla kuivainesisaldus kevadkatte kasutamisel oli hübriidsordil ‘Hasanski Sladki’ 21
°Brix, katete kasutamine kuivainesisaldust ei mõjutanud. Kevadine katmine mõjutas
hübriidsordi ‘Zilga’ mahla kuivainesisaldust, mis jäi vahemikku 14–16 °Brix. Kõige
kõrgem tulemus saadi katteloori kasutades. Sügiskatete kasutamisel varieerus sordi
‘Hasanski Sladki’ kuivainesisaldus vahemikus 20–21 °Brix, olles kõrgeim kilekatte
kasutamisel.
Orgaaniliste hapete sisaldus katsemarjade mahlas varieerus sordil ‘Hasanski Sladki’
vahemikus 0,51–0,63 mg/100g. Madalaim oli happesisaldus kilekatte kasutamisel ning
kõrgeim kattelooriga. ‘Zilga’ orgaaniliste hapete sisaldus varieerus vahemikus 0,38–0,54
mg/100g. Kõige kõrgem tulemus saadi varjutuskanga kasutamisel ning madalaim
kilekattega. Sügiskatete kasutamisel varieerus sordi ‘Hasanski Sladki’ orgaaniliste hapete
sisaldus vahemikus 0,62–0,85 mg/100g, olles kõrgeim linnuvõrguga variandis ning
madalaim varjutuskangaga.
Mahla pH jäi kevadkatteid kasutades sordil ‘Hasanski Sladki’ vahemikku 3,7–3,9,
kõrgeim oli tulemus kilekatte kasutamisel ning madalaim kontrollvariandis. Sort ‘Zilga’
mahla pH varieerus vahemikus 3,1–3,5, kõige kõrgem oli pH kilekatet kasutades ning
madalaim varjutuskangaga. Sügiskatteid kasutades jäi ‘Hasanski Sladki’ pH vahemikku
3,6–3,8. Kõige kõrgem oli pH kilekatte kasutamisel, teiste katsevariantide pH oli 3,6.
Tööst järeldus, et katete kasutamisega kevadel ja sügisel on võimalik mõjutada marjade
tehnoloogilist küpsust. Senised katsed viinapuude katmisega on toimunud erakordselt
jaheda (2017) või kuuma (2018) suve tingimustes, mis on oluliselt mõjutanud ka tulemusi.
Katete mõju hindamine vajaks täiendavaid uuringuid.
The maturity of grapes at harvest determines the style and quality of the wine. Technological maturity is assessed on the basis of dry matter, organic acids and pH of berry juice. Previous testing in Estonia has shown that due to relatively cool summers the acidity in berries remains too high and sugar content too low. However, the biochemical composition of berries can be manipulated by different viticultural techniques. In the summer of 2017, covering of the fruiting zone after verasion was studied at the Estonian University of Life Sciences, but several key processes in berry development take place in earlier stages. Thus, the hypothesis was that spring and autumn covers can affect the ripening process and the technological maturity of grapes. The aim of the study was to evaluate the effect of covers on the technological maturity parameters of hybrid varieties 'Zilga' and 'Hasanski Sladki': the dry matter content, organic acids and pH in juice. The testing was carried out in 2018 under open field conditions at the Rõhu Testing Station of the Estonian University of Life Sciences in Tartu County. Hybrid varieties 'Hasanski Sladki' and 'Zilga' were studied. Plastic cover, shading fabric and polypropylene fabric were used as covering materials. Spring covers were installed on both varieties from 16th of May to 11th on June. The control group of 'Hasanski Sladki' variety consisted of uncovered vines, while there was no control group 'Zilga'. Autumn covers were only applied to 'Hasanski Sladki' vines that were not covered in spring. Autumn covers were in use from 16th of August to 19th of September. The dry matter content of the juice of 'Hasanski Sladki' was unaffected by the use of spring covers, resulting in 21 Brix °.Spring covers did affect the dry matter content of the juice of the hybrid variety 'Zilga', which ranged from 14 to 16 Brix °.The highest result was obtained with using a polypropylene fabric. With autumn covers, the dry matter content of the 'Hasanski Sladki' variety ranged from 20 to 21 Brix °, reaching the highest levels with plastic cover. The content of organic acids in berry juice varied from 0.51 to 0.63mg / 100g in the 'Hasanski Sladki' variety. Acidity was the lowest in berries covered with plastic and highest in berries covered with polypropylene fabric. Organic acid content of 'Zilga' ranged from 0.38 to 0.54 mg / 100g. The highest result was obtained with the use of the shading fabric and the lowest with plastic cover. With the use of autumn covers, the range of organic acids in 'Hasanski Sladki' ranged from 0.62 to 0.85mg / 100g, being the highest with the use of bird netting and the lowest with the shading fabric. With the use of spring covers, the pH levels of the berry juice of 'Hasanski Sladki' ranged from 3.7 to 3.9, reaching their highest with plastic cover and lowest in control group. The pH levels of the variety 'Zilga' ranged from 3.1 to 3.5, reaching their highest with plastic cover and lowest with shading fabric. With the help of autumn covers, the pH levels of 'Hasanski Sladki' ranged from 3.6 to 3.8. The pH levels were the highest when the plastic cover was used, the pH level of the other test variants was 3.6. The study concluded that the use of covers in spring and autumn can influence the technological maturity of grape berries. So far the tests have been made in exceptionally cool (2017) and hot (2018) summer conditions, which have also had a significant impact on the results. The assessment of the impact of covers would require further research.
The maturity of grapes at harvest determines the style and quality of the wine. Technological maturity is assessed on the basis of dry matter, organic acids and pH of berry juice. Previous testing in Estonia has shown that due to relatively cool summers the acidity in berries remains too high and sugar content too low. However, the biochemical composition of berries can be manipulated by different viticultural techniques. In the summer of 2017, covering of the fruiting zone after verasion was studied at the Estonian University of Life Sciences, but several key processes in berry development take place in earlier stages. Thus, the hypothesis was that spring and autumn covers can affect the ripening process and the technological maturity of grapes. The aim of the study was to evaluate the effect of covers on the technological maturity parameters of hybrid varieties 'Zilga' and 'Hasanski Sladki': the dry matter content, organic acids and pH in juice. The testing was carried out in 2018 under open field conditions at the Rõhu Testing Station of the Estonian University of Life Sciences in Tartu County. Hybrid varieties 'Hasanski Sladki' and 'Zilga' were studied. Plastic cover, shading fabric and polypropylene fabric were used as covering materials. Spring covers were installed on both varieties from 16th of May to 11th on June. The control group of 'Hasanski Sladki' variety consisted of uncovered vines, while there was no control group 'Zilga'. Autumn covers were only applied to 'Hasanski Sladki' vines that were not covered in spring. Autumn covers were in use from 16th of August to 19th of September. The dry matter content of the juice of 'Hasanski Sladki' was unaffected by the use of spring covers, resulting in 21 Brix °.Spring covers did affect the dry matter content of the juice of the hybrid variety 'Zilga', which ranged from 14 to 16 Brix °.The highest result was obtained with using a polypropylene fabric. With autumn covers, the dry matter content of the 'Hasanski Sladki' variety ranged from 20 to 21 Brix °, reaching the highest levels with plastic cover. The content of organic acids in berry juice varied from 0.51 to 0.63mg / 100g in the 'Hasanski Sladki' variety. Acidity was the lowest in berries covered with plastic and highest in berries covered with polypropylene fabric. Organic acid content of 'Zilga' ranged from 0.38 to 0.54 mg / 100g. The highest result was obtained with the use of the shading fabric and the lowest with plastic cover. With the use of autumn covers, the range of organic acids in 'Hasanski Sladki' ranged from 0.62 to 0.85mg / 100g, being the highest with the use of bird netting and the lowest with the shading fabric. With the use of spring covers, the pH levels of the berry juice of 'Hasanski Sladki' ranged from 3.7 to 3.9, reaching their highest with plastic cover and lowest in control group. The pH levels of the variety 'Zilga' ranged from 3.1 to 3.5, reaching their highest with plastic cover and lowest with shading fabric. With the help of autumn covers, the pH levels of 'Hasanski Sladki' ranged from 3.6 to 3.8. The pH levels were the highest when the plastic cover was used, the pH level of the other test variants was 3.6. The study concluded that the use of covers in spring and autumn can influence the technological maturity of grape berries. So far the tests have been made in exceptionally cool (2017) and hot (2018) summer conditions, which have also had a significant impact on the results. The assessment of the impact of covers would require further research.
Kirjeldus
Magistritöö
Aianduse õppekaval
Märksõnad
magistritööd, viinapuu, orgaanilised happed, pH, katted, mahla kuivamine