| Abstract | U današnje vrijeme primjena mreža se smatra neizostavnom mjerom pri uzgoju mnogih voćnih vrsta. Cilj ovog istraživanja je bio istražiti utjecaj novog agro-tehnološkog koncepta, primjene anti-insekt fotoselektivnih mreža na vegetativne i generativne parametre breskve ´Suncrest´. Istraživanje je provedeno 2015. godine u nasadu bresaka u mjestu Vratišinec, pokraj Čakovca. U istraživanju su se primijenile Agritenax crvena, Agritenax bijela i Agritenax žuta (proizvođač Tenax, Italija)) mreža (veličina okca 2,4 × 4,8 mm) te Stop Drosophila Normal (proizvođač Artes Politecnica, Italija)) mreža (SDN) (veličina okca 0,90 × 1 mm), koja je prema specifikacijama proizvođača bijele boje. Plodovi su uslijed promjena u dinamici dozrijevanja te lakše manipulacije brani u dva roka berbe, odnosno u prvom roku brane su breskve uzgajane ispod žute i SDN mreže te u prirodnim uvjetima (bez primjene mreža); a u drugom roku breskve uzgajane ispod bijele i crvene mreže te u prirodnim uvjetima. U usporedbi s prirodnim uvjetima primjena mreža, s izuzetkom SDN mreže, je značajno povećala površinu lista i duljinu plojke lista bresaka. Primjena mreža nije ostvarila značajan utjecaj na prirod i učinkovitost priroda, ali je primjena bijele mreže povećala masu ploda. Najizraženije reducirano dopunsko obojenje bilo je na plodovima bresaka uzgajanih ispod SDN mreže, a najmanje na onim ispod žute mreže, temeljem parametara i indeksa boje. S druge strane dopunska boja ploda je bila manje reducirana na plodovima bresaka uzgajanima ispod bijele i crvene mreže, a najblaže ispod žute mreže. Plodovi uzgajani ispod SDN i žute mreže imali su značajno veću tvrdoću, titracijsku kiselost te manji omjer topljive suhe tvari i titracijske kiselosti u odnosu na plodove uzgajane u prirodnim uvjetima. Također plodovi bresaka uzgajanih ispod SDN mreže su imali izraženije manji prosječan sadržaj topljive suhe tvari u usporedbi s onima u prirodnim uvjetima. Sličan, ali u određenom dijelu slučajeva trend na temelju prosječnih vrijednosti je zabilježen i u bresaka uzgajanih ispod crvene i bijele mreže. Primjena mreža je ostvarila značajan utjecaj na sadržaj brojnih bioaktivnih komponenti u plodu (ukupni polifenoli, ABTS i DPPH antioksidacijski kapacitet, udio ukupnih antocijana) te je navedeni utjecaj u većini slučajeva (ali ne i svima) bio negativan. Također plodovi bresaka uzgajani ispod žute mreže su imali značajno veći udio pektina topivih u lužini u odnosu na one u prirodnim uvjetima, dok nije zabilježen značajan utjecaj mreža na udio ostalih pektinskih frakcija. Na temelju rezultata ovog istraživanja može se u agroekološkim uvjetima sjeverne Hrvatske preporučiti primjena crvene, bijele te pogotovo žute mreže na breskvu ´Suncrest´ jer korist od njihove primjene (zaštita od tuče, vjetra, insekata itd.) nadilazi blagi negativan utjecaj na kvalitetu ploda (koji je sa žutom mrežom bio minimalan). |
| Abstract (english) | Nowadays, the application of nets is considered an indispensable measure in the cultivation of many fruit species. Nets are mainly used in order to protect fruit trees from: hail, heavy rain, snow, wind, excessive solar radiation, birds and recently from insects. Anti-insect nets present a new, environmentally friendly pest-control approach where nets, due to their smaller mesh size, present a mechanical barrier to the pest and hence protect the fruit trees. Also, lately a new agro-technological approach has emerged – the photoselective nets. The main goal of this approach is to promote the desired plant physiological responses by the means of light manipulation, while at the same time physically protecting plants from usual hazards. Hence, the aim of this thesis has been to study how different photoselective anti-insect nets affect vegetative and generative parameters of peach 'Suncrest'.
Following nets were applied: Agritenax red, Agritenax white and Agritenax yellow (producer Tenax, Italy)) (mesh size 2.4 × 4.8 mm) and Stop Drosophila Normal (producer Artes Politecnica, Italy)) net (SDN) (mesh size 0.90 × 1 mm), which according to the specifications of the producer is white. The experiment was set up according to a random block schedule in three repetitions for each net and control (natural conditions). Each repetition included three peach trees. Research was carried out in 2015 in a peach orchard located in Vratišinec, near Čakovec. Peach trees were grafted on vineyard peach and grown as a vase. Standard agro and pomo technical measures (pruning, fertilization, mowing, pesticide application, irrigation etc.) were regularly carried out in the orchard. Nets were applied after the end of bloom period of the peach trees. Fruit was harvested on two harvest dates. On the first harvest date fruit of peaches grown under the yellow net, SDN net and from the natural conditions was harvested, while on the second harvest date fruit of peaches grown under the red net, white net and from the natural conditions was harvested.
Application of the nets significantly increased peach leaf area and leaf blade length, with the exception of the SDN net which, in relation to the natural conditions, did not achieve a significant impact. Leaves of peaches grown under the SDN net had significantly smaller petiole length than those under the red net, while in relation to those from the natural conditions no significant difference was recorded. Other vegetative parameters (shoot length, shoot diameter, length of internodes, density of internodes, trunk cross sectional area, leaf blade width, leaf shape index) as well as majority of productivity parameters (yield, yield efficiency) were not significantly affected by the application of the nets. However, the peaches grown under the white net had significantly higher fruit weight than those under the yellow net, SDN net and in the natural conditions. Based on the fruit colour parameters and indexes, application of the SDN net most notably reduced additional fruit coloration. However, additional colouration was less reduced on fruit of peaches grown under the white and red nets, while minimally reduced of those under the yellow net. Peaches grown under the SDN and yellow nets had significantly higher fruit firmness and titratable acidity, as well as smaller total soluble solids and titratable acidity ratio than those grown in the natural conditions. Also, application of the SDN net on average level more notably reduced total soluble levels in fruit. Similar, but in some cases trend based on average values, was recorded for the peaches grown under the red and white nets. Application of the yellow, white and SDN nets significantly reduced total polyphenol content. ABTS antioxidant capacity was significantly reduced in fruit grown under the yellow and SDN nets, while DPPH antioxidant capacity in fruit grown under the yellow and white nets. Total anthocyanin content was significantly reduced in fruit of peaches grown under all nets, with exception of those under the yellow net. Peaches grown under the yellow net had significantly higher share of alkali-soluble pectin than those grown in the natural conditions. Application of all
nets did not achieve significant effect on β-carotene content and share of other pectin fractions. To conclude, in agro-ecological conditions of northern Croatia, application of the red, white and especially the yellow net on peach ´Suncrest´ can be recommended, since the benefits of their application (protection from hail, wind, insects etc.) outweigh the mild negative impact on fruit quality (which under the yellow net was minimal). However, given that the pest Drosophila suzukii (for the purpose of which the SDN net was designed) in the Republic of Croatia does not yet cause serious damage to peaches, the application of the SDN net is not recommended due to a significant fruit quality reduction (except in cases where other protective measures are not available). |
