Effect of partial leaf removal on natural fruitlet shedding and quality of apple fruits (Malus domestica Borkh.) variety \u27Golden delicious\u27.

Leta 2016 smo ugotavljali, kako delna odstranitev rozetnih listov vpliva na naravno trebljenje plodičev. V poskus smo vključili tri obravnavanja in med cvetenjem ob cvetnem šopu odstranili 2/3, 1/3 in nič listov. Nato smo spremljali odpadanje plodičev med junijskim trebljenjem in prešteli ostale plodove ob obiranju. Analizirali smo kakovost plodov (maso, premer, trdoto (kg/cm²), topno suho snov (°Brix) in test z jodovico) in s HPLC metodo izmerili vsebnost sladkorjev (fruktoze, glukoze, saharoze, sorbitola) in organskih kislin (fumarne, šikimske, jabolčne in citronske kisline). Naravno trebljenje plodičev je bilo pri 1/3 in 2/3 odstranjenih listov večje kot pri polnoolistani kontroli. Po posameznih pozicijah je v največ primerih ostal centralni oz. kraljevi plod (K), pri polnoolistanih drevesih pa je stranski plod (L1), ki je bil najbližje (K) plodu, odpadel v večjem številu kot pri drevesih z zmanjšano listno površino. Pri obravnavanjih z večjim deležem odstranjenih listov so plodiči na pozicijah (L1–L4) pogosteje odpadli. Kakovost plodov se je razlikovala po obravnavanjih. Največ skupnih sladkorjev so vsebovala jabolka pri 2/3 odstranjenih listov, skupne organske kisline pa so bile v največjih deležih pri 2/3 in 0 odstranjenih listov. Prirast enoletnega lesa je bil statistično značilno največji pri obravnavanju z neodstranjenimi listi.We studied the effect of partial spur leaf removal on fruitlets shedding in 2016. Three treatments were included in the experiment with 2/3, 1/3 and 0 spur leaf area removal. We monitored the fruitlets shedding during the June drop and at the harvest of the remaining fruit, we counted the rest of it. At harvest, the quality parameters of fruits were measured (fruit weight, fruit diameter, firmness (kg/cm²), total soluble solids (°Brix) and maturity index) and the content of the sugars (fructose, glucose, sucrose and sorbitol) and the organic acids (fumaric, shikimic, malic and citric acid) were determined and analysed using HPLC system. In the treatments where 1/3 and 2/3 spur leaf area were removed, the natural fruit drop was greater than in the treatment with no spur leaf area removal. The king flower (K) remained in most cases. While the lateral fruitlets (L1) which were closest to the king fruitlets dropped in the most cases in the treatment where no spur leaves were removed. With a higher proportion of leaf area removal, the fruitlets abscission was more intensive at lower positions (L1-L4). The quality of fruits varied among the treatments. The highest levels of total sugars were measured in apples where we removed 2/3 of the leaf area, while total organic acid were in high levels at 2/3 and 0 leaf area removal. The one-year shoots growth was statistically significant highest in the treatment with no removed leaves