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V okviru projekta visokostorilna trajnostna pridelava jabolk je zajeta tematika spravila pridelka, ki se osredotoča predvsem na izhodišča za praktično uvajanje strojev s ciljem povečanja storilnosti obiranja. Glede na izhodiščne pogoje sadjarskega obrata se pridelovalci poslužujejo različnih tehnologij spravila pridelka, kar izhaja iz izjemno različnih pridelovalnih pogojev, ki smo jih priča v Sloveniji. Prispevek opisuje različne pristope k organizaciji obiranja, uporabi opreme in strojev za povečanje učinkovitosti ter navodila k načrtovanju in organizaciji spravila ob hkratnem upoštevanju tehnoloških zahtev in obiralnih oken.

The preservation of biodiversity and the improvement of soil fertility have become important goals in orchard management; therefore, the standard approach of weed control in the understory of tree rows by repeated frequent use of herbicides needs to be replaced by more sustainable methods. This study presents a technique for establishing a permanent autoregulatory non-competitive plant community as an alternative to herbicide treatment. For a practical demonstration of this weed control method, an experiment was conducted in a pear orchard during the 2015–2019 growing seasons. A permanent plant community was created in a 1 m wide strip under the trees by seeding three different grass and herb mixtures. Two types of control plots were also established (weed control treated with the herbicide glyphosate and weedy control). Several inventories of the species composition of the studied communities were conducted each season. The relationship between the proportions of plant biomass of native, non-seeded plants, and seeded plants was evaluated. The results of this experiment show that the long-term undisturbed development of understory communities not exposed to herbicides or mechanical weed control causes only a limited, statistically non-significant reduction in yield.

An experiment on chemical blossom thinning on apple variety 'Summerred'/ M9 was performed in an experimental plantation in Brdo pri Lukovici. Different chemical thinners were applied on apple’s fruitlets in organic production. The experiment was designed in 7 randomized block with 13 treatments: 1. unthinned trees (as a control), 2. hand thinning in June, 3. 1% NaCl, 4. 1,5% NaCl, 5. 1% CH3COOH, 6. 3% CH3COOH, 7. 3% CaSx, 8. 1% rape oil, 9. 3% rape oil, 10. 3% of sunflower oil, 11. 3% soybean oil, 12. 5% dextrin, 13. emulsifier 100 + OCA 30. Chemical thinners were applied in a phenological stage at peak blooming with a manual knapsack sprayer. The best thinning of fruitlets (similar to hand thinned trees) was observed with 3% rape oil, however, relatively strong russeting of fruit skin was detected in this treatment. Statistically significant reduction of final fruit set also occurred when 1,5% NaCl and 3% soybean oil were applied, but with less fruit russeting., Na eksperimentalnoj plantaži (Brdo pri Lukovici) proveden je pokus kemijskog prorjeđivanja cvjetova jabuke sorte ‘Summerred’ cijepljene na podlozi M9. Cilj eksperimenta bio je ispitati učinke različitih sredstava koji se koriste u jabukama u ekološkoj proizvodnji. U pokusu sa 7 randomiziranih blokova i 13 tretmana proučavan je utjecaj: 1. neprorijeđeno, 2. ručno rijeđeno u lipnju, 3. 1% NaCl, 4. 1,5% NaCl, 5. 1% CH3COOH, 6. 3% CH3COOH, 7. 3% vapneni sumpor CaSx, 8. 1% ulje uljane repice, 9. 3% ulje uljane repice, 10. 3% suncokretovo ulje, 11. 3% sojino ulje, 12. 5% dekstrin, 13. emulgator 100 + OCA 30. Kemijski prorjeđivači primijenjeni su u fenološkom stadiju u vrhuncu cvjetanja. Najbolje prorjeđivanje plodova, slično onima s rukom, zabilježeno je pri nanošenju 3% ulja uljane repice. Prilikom ovog tretmana uočena je razmjerno jaka rđavost kože ploda. Statistički značajna manji broj plodova također se pojavilo kada je raspršeno 1,5% NaCl i 3% sojinog ulja, ali s manje izraženom rđavošću jabuka.

Geomorphologic characteristics like altitude and terrain slope have an important but often neglected impact on light conditions in orchards. The study concentrated on the impact of altitude and terrain slope in combination with various colours of anti-hail nets (red, grey, blue, green and black) on the light and microclimate conditions in apple orchards. The results exhibit a large reduction of the photosynthetically active radiation (PAR) under the nets, most prominently under blue and red nets (reduction between 38.7 and 45.6%), while the impact of coloured nets on other microclimatic parameters (average air temperature, relative air humidity, temperature of dew point, wet-bulb temperature, heat index, minimum air temperature, maximum air temperature) remain irrelevant. The only consistent difference is an average of 2% increase of maximum air temperature under the blue net in comparison to other treatments. The use of the net also significantly reduce the wind speed (on average by 56.3%) and air flow (on average by 63.4%), and changes the distribution of precipitation in the orchard, most prominently in cases of heavy rain and drizzle. Regarding the orchard’s geomorphologic characteristics, a positive relationship exists between altitude and PAR., Geomorfološke lastnosti, kot so nadmorska višina in naklon terena, imajo pomemben in pogosto spregledan vpliv na svetlobne razmere v nasadih. V raziskavi je bil preučevan vpliv nadmorske višine in naklona terena v kombinaciji z različnimi barvami protitočnih mrež (rdeča, siva, modra, zelena in črna) na svetlobne in mikroklimatske razmere v nasadu jablan. Rezultati kažejo veliko zmanjšanje fotosintetskega aktivnega sevanja (PAR) pod mrežami. Najbolj izrazito zmanjšanje PAR je pod modro in rdečo mrežo (med 38,7 in 45,6%). Vpliv barvnih mrež na druge mikroklimatske parametre (povprečna temperatura zraka, relativna zračna vlažnost, temperatura rosišča, temperaturna točka vodne kapljice, indeks toplote, minimalna temperatura zraka, maksimalna temperatura zraka) je neizrazit. Glede na ostala obravnavanja je ugotovljena le konsistentna in v povprečju za 2% višja maksimalna temperatura zraka pod modro mrežo. Uporaba mrež tudi bistveno zmanjša hitrost vetra (v povprečju za 56,3%) in pretok zraka (v povprečju za 63,4%) ter spremeni porazdelitev padavin v sadovnjaku, najizraziteje v primeru močnega dežja in rosenja. Glede na geomorfološke značilnosti sadovnjaka je gotovljena pozitivna povezanost med nadmorsko višino in PAR.

Selection of a proper cultivar is one of the most important management decisions when investing into apple orchard. This paper presents a methodology for evaluation of suitability for cultivation of some apple cultivars by using a multi-criteria model based on analytical hierarchy process. The software tool Expert Choice was used to support growers in making decisions about which new apple cultivar to grow. The model was applied to 13 cultivars with data derived from questionnaires completed by group of experts of different fields (orchardists, experts for fruit production economics and fruit marketing, cultivar breeders, experts of state service and commission for introduction of new cultivars, experts for fruit storage and fruit quality assessment, plant protection and fruit growing advisers). The results are shown as priority for individual cultivar. The potential of the model for assessing apple cultivar is demonstrated with the aim of providing a comprehensive explanation and justification of the assessment technique. It also indicates strong and weak points (in market potential, fruit estimation, production demands and tree estimation) of each assessed cultivar.

During the 2008–2010 growing seasons, an alternative ‘zero residue apple production system’ was compared with integrated apple production with cvs ‘Idared’, ‘Golden Delicious’, ‘Jonagold’ and ‘Gala’ in commercial orchards at several locations throughout Slovenia, using data envelopment analysis (DEA), and multi criteria assessment by an analytical hierarchical process (AHP). The principle of the ‘zero residue apple production’ is a combination of integrated (IP) and organic apple production. During the first 3 months of the growing season (1 April–30 June), pesticides used in IP with rapid degradation (8–10 applications) were used to control pests and diseases. During the second part of the season from 1 July to harvest, organic products (6–12 applications) were employed compared with 19–25 applications overall in IP. The goal of the alternative system was to reduce the amount of applied conventional pesticides by 40 % and to minimize pesticide residues in fruits to below the limit of 0.5 % of the legal maximum residue level (MRL) or below the residue concentrations of 0.005–0.01 mg/kg and to retain the high long-term level of yield, fruit quality, and net income per hectare. The number of pesticide residues was reduced from 4.2–5.5 in IP to 1.8–3.4 in zero residue cultivation, while 3 year average yields (class 1 fruit) were 4–9 % lower than in IP. The break even prices ranged from € 0.31 for Idared in IP, € 0.34 for ‘Elstar’ of both production systems to € 0.35/kg for zero residue cultivated ‘Golden Delicious’. Overall, a price increase of just € 0.02/kg for residue free apples would make this new ‘zero residue apple production’ profitable then representing a realistic alternative to the standard integrated apple production system.

Fruit pigmentation in ripening cv. ‘Gala, Schniga’ apples was monitored under the influence of fertigation weekly during 21 July–31 August 2009, i.e. 34 days before and 7 days after the optimal harvest date in Slovenia. The soil was a heavy loam clay with high humus content (2.8 %) and high acidity (low pH 4.9). The spectral indices NDVI (Normalized Difference Vegetation Index) and NAI (Normalized Anthocyanin Index) were obtained by a PA 1101 on attached fruit on the transition between the ground and blush colour of the fruit surface. NAI increased slowly from 0.25 to 0.6 two weeks prior to optimum maturity. NDVI values fell from 0.9 to 0.2 before and during ripening, with significant changes starting ca. 3 weeks before and during the week after the optimum harvest date. Fertigation delayed fruit ripening viz harvest date by ca. 4 days. Fertigation delayed changes in the intensity of the fruit’s epidermal pigments, expressed as NDVI for 1 week and NAI for 4 weeks, respectively, but had no significant effect on fruit colour or NDVI and NAI values at the optimal harvest date. At this time, those fruits from the fertigated trees were firmer with a lower starch index compared with the un-fertigated control. Statistically, highly significant correlations were found (p ≤ 0.01) (r = 0.35 to r = 0.91, R2 = 0.11–0.83) between all the studied spectral and standard parameters i.e. fruit fresh firmness, soluble solids content and starch index.

Field trials were carried out from 2008 to 2011 at Maribor, Slovenia to determine the effect of new copper fungicide formulations on the copper content in apple fruits, separated in peel and flesh, of seven cultivars at harvest. Apple trees were treated 12–18 times per season with formulations based on copper oxychloride or sulphate (trial standards), copper hydroxide and their complexes or chelates with amino acids, peptides, EDTA, urea, and octanoic or gluconic acids at the same rate of 200 g of pure copper ions (Cu2+) per hectare irrespetive of the product. Copper formulations were applied with Teejet 800067 flat fan nozzles mounted on a vertical boom of the sprayer, which gave a droplet volume median diameter (VMD) of 120 microns and 130–180 droplet impacts per square centimeter, as determined on water sensitive papers. The new formulations of copper in the form of salts of fatty acids or organic complexes or chelates had a higher penetration rate into apple fruit tissue than the traditional formulations based on Cu-hydroxide, Cu-oxychloride and Cu-sulphate. The copper content in the fruit depended on the ratio between copper solubility in the formulation, rate of penetration into the fruit and stability of the copper fungicide deposit on the fruit surface. Despite being applied at lower hectare rates, frequent applications led to the exceeding of the permitted EC maximum residue level of 5 mg/kg fresh mass (FM). MRL was most often exceeded with the application of formulations based on Cu-octanoate and Cu-gluconate and less often in case of the application of complexes of copper with amino acids, peptides or urea. A comparison of the copper content between different cultivars showed that cv. ‘Jonagold’, ‘Golden Delicious’ and ‘Elstar’ accumulated more cooper than other cultivars. Copper concentrations in the peel exceeded that of the flesh at least twice. The potential effects of accumulation of copper in woody tissue of bearing shoots after long-term application of highly systemic copper formulations on growth and blooming of apples are discussed too. Some apple growers may not be aware of much higher penetration rate of these new copper products (fungicides, fertilisers or plant strengtheners) and should be warned about the necessity to adapt their spraying schedules despite applications of a low hectare rates of copper, i.e. the number of treatments and proper seasonal timing, to avoid exceeding of EU MRL of copper in fruit.

Streuobst stands, i.e., tall fruit trees on vigorous rootstock on traditional grassland, represent an important source of raw material for the processing industry and for traditional fruit processing on family-run farms. Apart from production aspects, the high-stem orchards also play a role in the conservation of the traditional landscape, and indirectly in maintenance of the viability of rural areas. In this paper, a qualitative multi-attribute model for the assessment of Streuobst stands with respect to their multifunctional characteristics is presented. The assessment is based on four groups of attributes: (1) production criteria (percentage of missing trees), (2) biodiversity (fruit species and varieties, artificial human intervention), (3) landscape diversity (visual appearance, eco-diversity and erosion protection), and (4) function of the stand (row or individual trees, countryside appearance). The assessment is based on the aggregation of input attribute values to an overall assessment through user-defined decision rules. The model was applied to 85 sample stands in NE Slovenia. The assessment shows that most of the stands (48) were rated as “very poor” or “poor”, mainly as a result of poor cultivation and lack of maintenance.

Abscission of apple (Malus ×domestica Borkh.) fruitlets is associated with increased ethylene evolution, although the role of ethylene is not clear. Fruitlet ethylene evolution and expression of ethylene-related MdACO1, MdACS5A, and MdACS5B genes were followed in the abscission zone (AZ) and fruit cortex (FC) of king and lateral fruitlets of ‘Golden Delicious’/M.9 after spraying with 15 mg·L−1 naphthaleneacetic acid (NAA), 150 mg·L−1 6-benzyladenine (BA), 500 mg·L−1 ethephon, and after 3 days 96% shading, all applied at a mean 10 mm fruitlet diameter. Lateral fruitlets (LF) were more susceptible to abscission after treatment with chemical thinners or shading compared with king fruitlets (KF) in which only ethephon-treated KF abscised later. On KF, only ethephon increased fruitlet ethylene evolution, MdACO1 expression in FC and AZ 8 days after treatment (DAT), and abscission of KF 10 DAT, but the other treatments did not. Although ethephon increased MdACO1 expression in FC of KF 8 DAT, the expression of MdACS5A and MdACS5B remained unchanged. On LF, all treatments at 8 DAT increased ethylene evolution and MdACO1 expression in FC and enhanced abscission 10 to 22 DAT. Expression of MdACS5A and MdACS5B in FC of LF 8 DAT was expressed at a lower level compared with MdACO1. In the AZ of both KF and LF, only ethephon increased expression of MdACO1, MdACS5A, and MdACS5B.

The purpose of this study was to evaluate the contribution of extractable antioxidants and non-extractable phenolics to the total antioxidant activity (TAA) of plums. Therefore, the antioxidant activity was determined (ABTS assay) in aqueous–organic extracts, as well as in the extraction residues which were a subject of two different acidic treatments to release hydrolysable tannins and non-extractable proanthocyanidins (NEPA). In addition, the changes in TAA during the last week of ripening were investigated. Extractable antioxidants contributed less than 18% to the TAA, considerably higher values of antioxidant activity were associated with hydrolysable tannins and NEPA, suggesting that the antioxidant activity of plums may be underestimated in the literature. The ripening resulted in an increase of TAA up to 38% in excess of the value determined on the first sampling date. TAA showed a similar pattern over the ripening period for all cultivars studied.

BACKGROUND: In managing apple orchards, crop load and rate of nitrogen (N) fertilisation are two factors with a significant influence on fruit quantity and quality, because they affect all physiological processes in the tree. Both factors are strongly related to external and internal fruit quality, especially to skin colour, sugar and acid contents and mineral composition, and consequently to the keeping quality of fruits. The aim of this study was to assess the effects of both factors (three crop load levels and two N fertilisation levels) on the colour development of Golden Delicious apples during the last month on the tree in two consecutive seasons. Data on skin colour (L*, a*, b* values) were analysed using nonlinear mixed effects modelling to extract information on the variation in biological shift factor for colour and to link this variation to the different strategies used concerning N fertilisation and crop load. RESULTS: The major source of information is contained in the a* value. The behaviour of the a* value could be described by a logistic or an exponential model depending on the season and the experimental set-up. Nonlinear mixed effects analysis estimating the biological shift factor (maturity) for each individual fruit (random effect) while estimating the rate constant of the decolouration process in common (fixed effect) resulted in explained parts well over 95%. CONCLUSION: The variation in maturity stage between individual fruits is large. Season has the most profound effect on the estimated values, far more important than that of crop load or fertilisation level. The magnitude of variation in colour due to crop load and N fertilisation is not too large. Its effect on the maturity stage of fruits is more profound: the higher the crop load, the higher the variation. The effect of fertilisation seems to be opposite: the higher the fertilisation level, the lower the variation.

Streuobstbestande auf Hochstammen bereichern einerseits das Landschaftsbild, andererseits liefern sie grose Obstmengen fur die Ernahrungsindustrie und fur die traditionelle bauerliche Obstverarbeitung (Weinherstellung, Brennen, Trockenobst, Apfelessig, Apfelkompott und Apfelmus). Weiterhin tragt der Streuobstbau in einem dicht besiedelten Land zur Vernetzung naturlicher Lebensraume bei. Ziel dieser Arbeit ist die Entwicklung eines Modells zur Bewertung bestehender Streuobstanlagen in Slowenien, das sich u. U. auf andere Lander ubertragen lasst. Das Modell ermoglicht eine empirische Bewertung bestehender Streuobstanlagen und wurde bei einer Erhebung von 51 zufallig ausgewahlten Streuobstbestanden in Nordostslowenien erfolgreich angewendet.

The trial was conducted in a ‘Gala’/M9 orchard and the experiment was designed as a randomized block comprising four treatments (application of Prohexadione-Ca: 125 mg-l, 250 mg-l, 2 x 125 mg-l, and control - without growth regulator). Experiments have been carried out for 2 years (2003, 2004). Application of Regalis reduced trunk cross-sectional area increment, and cumulative extension shoot growth. The effect increasing with concentration, and a greater inhibition was obtained when the trees were sprayed two times. Compared to control, return bloom of Regalis-treated trees was not affected. No negative effects of treatment with Regalis on yield per tree were observed, but some reduction of average fruit weight was found.

Colour and taste are important attributes of apple fruit quality and have therefore been widely studied. Nevertheless, because of the destructive sampling methods commonly used to obtain the data, and of the subsequent traditional analyses, ignoring the effects of biological variation, the knowledge on the kinetic mechanisms of synthesis and degradation of individual quality components during fruit development and growth is still lacking. Spatio-temporal changes of taste components (sugars: fructose, sucrose, glucose, organic acids: malic, citric, shikimic and fumaric acid) and colour aspects (a) in individual apple fruits were monitored to assess the dynamics and mechanisms of change during development and ripening with respect to location within fruit as a factor and the variation between individual apples. Data were analysed with non-linear indexed regression based on either a logistic or an exponential process oriented model assessing the technical variation simultaneously. The rate constants for colour or taste component were roughly similar between cultivars, suggesting a similar mechanism of development and confirming the generic nature of the model. There was a very large biological variation in individual quality components observed in the raw data (the biological variation), which can be almost exclusively explained by the difference in the maturity stage between individual fruit. The explained parts (R2 adj) were, with one exception, higher than 0.90. The major contribution of this study is the fact that all the herein monitored taste defining components can be analysed and described with the same process-oriented model.

The trial was conducted in 'Fuji'/M9 orchard in Slovenia with 5100 trees ha-1. The experimental design was as split-block comprising three rates of nitrogen (N) as broadcast fertilizer application with 60, 90 or 120 kg N ha-1, and three crop load (5.0, 3.5 or 1.5 fruits cm-2 trunk cross sectional area (TCSA)). Treatments with different N rates lasted two years beginning in the fourth year after planting. In the 4th growing season, crop load was adjusted by hand thinning whereas in the next year fruits were not thinned (control year). The major effect of excessive crop load on 'Fuji' apple was reduced return bloom. A positive relationship was found between N rates and TCSA in year of applied treatments and return bloom in control year. Results showed no significant effect of N treatment on size and internal fruit quality.

Investigations of the effect of foliar application of some nutrients and fertigation in comparison with broadcast nitrogen fertilization on mineral fruit composition of young apple 'Golden Delicious', grafted on M9 rootstock was conducted in years 2000-2001. Two orchard experiments were established, one with 2-year and the other with 3-year old trees, grown at a spacing of 3.2 x 0.7 m and trained to super spindle. In year 2000 fruits were hand thinned on 2-year and 3-year trees to 20 and 50 fruits/tree respectively. In 2001 fruits were not thinned because of low fruit set. The results showed no significant beneficial effect of applied treatments on fruit mineral content in both experiments. Ratios of N/Ca, K/Ca and (Mg + K)/Ca in fruits indicated good storage quality as related to normal crop load. On the contrary, when treatments were applied on trees with inadequate crop load, no beneficial effect occurred and fruits showed low storage life. This result illustrates the important balance between vegetative growth and fruit load that occurs during tree establishment.

Summary Investigations were made into axenically cultured long-short-day (LD-SD) plants Wolffia arrhiza, grown under 16 h LD and 8 h SD conditions and light intensity of 48 μmol · m−2 · s−1. The experiments were aimed at establishing the effects of GA3, EDDHA, and Mn-EDDHA, as well as their combinations on flowering. In the used concentrations under LD conditions, flowering was induced by GA3 (0.1−0.7 μmol · L−1) and by EDDHA (of 1.5–21 μmol · L−1). GA3 in higher concentrations (1.4–2.9 μmol · L−1) did not induce flowering. In the nutrient solution with Mn-EDDHA (1.5 μmol · L−1) flowering was promoted significandy under LD and SD conditions when compared with flowering in the same nutrient solution with an equivalent amount of manganese in the nonchelate form 1.5 μmol · L−1 MnCl2. Flowering was promoted to the greatest extent under LD conditions in the nutrient solution with Mn-EDDHA and the addition of combinations of = optimal concentrations of GA3 (0.4μmol · L−1) and EDDHA (19.5μmol · L−1). The obtained results also show that GA3, EDDHA and Mn-EDDHA may replace the SD requirement for flowering in the examined plants.

BACKGROUND: Homogeneity in appearance is one of the quality aspects asked for in the supply chain. Decreasing the biological variation in batches of harvested apples (cultivars Braeburn, Fuji and Gala) becomes increasingly important. Skin colour is one of the aspects that determine both optimal harvest and stage of development. Skin colour is affected by location in the canopy. The rules of development of biological variation are now established and will be used on skin colour data. RESULTS: The Minolta colour aspects a*, b* and L* measured before commercial harvest change in a sigmoidal fashion and can be analysed including the biological variation, with a logistic model in indexed nonlinear regression, obtaining explained parts of above 90%. The mechanism of colour change is not affected by state of development or location in the canopy. The location in the canopy affects the intensity of both red and green colouring compounds. The variation in colouration is not affected by the location in the canopy. CONCLUSION: The red-coloured apple cultivar (Gala) depends more on the location in the canopy than the less-coloured cultivars (Fuji and Braeburn). The colour development in Fuji apples is considerably slower, with a much larger variation in stage of development. The location in the canopy affects all aspects of biological variation (biological shift factor and asymptotic starting level of colouration) for all three colour aspects L*, a* and b*, but only the mean value, not the standard deviation. The biological shift factors per colour aspects are linearly related. Once induced, variation remains constant during development.

Colour is traditionally one of the important appearance features of all fruit for consumers in deciding to buy them. Colour is therefore important in the postharvest supply chain. But where does that colour of fruit come from? Clearly the period of growing and the circumstances during growth are important for developing this important feature. During several seasons (2007-2009), the skin colour of individual apples of different cultivars (‘Braeburn’, ‘Fuji’, ‘Gala’, ‘Golden Delicious’) were measured using a Minolta CR-400 chromameter during the last 40-60 days before (commercial) harvest. By including the biological variation between individual apples in the analyses and applying non linear indexed regression analysis based on process oriented models, explained parts were obtained for the a*-value, all exceeding 90%. The estimated rate constants for the colouration process were remarkably similar for all cultivars (except ‘Fuji’) and growing conditions. That would indicate that the process of colouration is really reflecting the degradation of chlorophyll and not the production of red or yellow coloured blush (anthocyanins). The expected effect of growing conditions (fertilization and crop level, hail net or not, sunny side or shady side of the tree) did change the mechanism nor the kinetic parameter values but could all be attributed to the minimal obtainable skin colour (asymptotic values of the logistic model). This type of information from the production period may constitute an important link to postharvest supply chain management.

BACKGROUND: In managing apple orchards, crop load and rate of nitrogen (N) fertilisation are two factors with a significant influence on fruit quantity and quality, because they affect all physiological processes in the tree. Both factors are strongly related to external and internal fruit quality, especially to skin colour, sugar and acid contents and mineral composition, and consequently to the keeping quality of fruits. The aim of this study was to assess the effects of both factors (three crop load levels and two N fertilisation levels) on the colour development of Golden Delicious apples during the last month on the tree in two consecutive seasons. Data on skin colour (L*, a*, b* values) were analysed using nonlinear mixed effects modelling to extract information on the variation in biological shift factor for colour and to link this variation to the different strategies used concerning N fertilisation and crop load. RESULTS: The major source of information is contained in the a* value. The behaviour of the a* value could be described by a logistic or an exponential model depending on the season and the experimental set-up. Nonlinear mixed effects analysis estimating the biological shift factor (maturity) for each individual fruit (random effect) while estimating the rate constant of the decolouration process in common (fixed effect) resulted in explained parts well over 95%. CONCLUSION: The variation in maturity stage between individual fruits is large. Season has the most profound effect on the estimated values, far more important than that of crop load or fertilisation level. The magnitude of variation in colour due to crop load and N fertilisation is not too large. Its effect on the maturity stage of fruits is more profound: the higher the crop load, the higher the variation. The effect of fertilisation seems to be opposite: the higher the fertilisation level, the lower the variation.

A trial was conducted over two years in a 'Topaz'/M9 orchard (4000 trees/ha) using a randomized block design comprised of five fertilizer treatments: 400 kg/ha Compo Guano (11% N), 880 kg/ha Maltaflor Special (5% N), 880 kg/ha Agrovit (5% N), 550 kg/ha Biosol (8% N) and an unfertilized control, and two types of orchard floor management: tree row clean-cultivated and grass within the tree row mowed. The treatments began in the third year after orchard establishment. Trunk cross sectional area (TCSA), the number of flower clusters per tree, fruit set, yield and average fruit weight were determined. The tree growth (TCSA increment) was significantly higher following treatments with Maltaflor Special and Agrovit than with Biosol. The cumulative yield per tree was higher following application of Agrovit than Biosol or Maltaflor Special, but no treatments significantly increased cumulative yield compared with the control. No significant differences were found for growth, yield and external fruit quality parameters for the other fertilizers and vegetation management methods, compared with the control.

The thinning response was studied on six years old trees of ‘Gala’/M.9. The treatments of single application of ethephon 200 ppm at the balloon stage, of naphthaleneacetic acid (NAA) 10 ppm or benzyladenine (BA) 100 ppm at 10 mm fruit diameter as well as the sequential treatments of ethephon followed by NAA or/and BA and tank mixed NAA + BA treatment were performed. A non significant thinning was obtained in treatments when ethephon, NAA and BA were used separately. No additional thinning occurred even in the combinations when ethephon was applied first at the balloon stage and NAA or BA applied later at 10 mm fruitlet diameter. Significant thinning response occurred only when tank mixed treatment of NAA + BA and sequential treatment of ethephon followed by tank mixture of NAA + BA were carried out. In this experiment, mean fruit weight and the share of bigger sized fruits (>70mm) increased significantly in all thinning treatments compared to the non thinned control trees., Proučavali smo odaziv prorjeđivanja na šest godina starim stablima sorte 'Gala'/M.9. Izvedeni su postupci pojedinačnih aplikacija etefona 200 ppm u fenofazi crvene glavice, naftiloctene kiseline (NAA) 10 ppm ili benziladenina (BA) 100 ppm kada je promjer ploda iznosio 10 mm kao i uzastopni postupci etefonom nakon čega je slijedila NAA, odnosno BA ili u tanku pomiješani NAA + BA. Prorjeđivanje nije bilo signifikantno kod postupaka, u kojima su etefon, NAA i BA primijenjeni pojedinačno. Do dodatnog prorjeđivanja nije došlo ni u postupcima kada je etefon primijenjen najprije u balonskom stadiju, a NAA ili BA primijenjeni kasnije, kada je promjer plodova iznosio 10 mm. Signifikantan odaziv na prorjeđivanje dogodio se samo kada je izveden postupak s u tanku pomiješanim NAA + BA i uzastopni postupak etefonom nakon čega su slijedili u tanku pomiješani NAA + BA. U tom pokusu prosječna težina plodova i udio većih plodova (> 70 mm) signifikantno su se povećali kod svih postupaka prorjeđivanja u usporedbi s neprorjeđivanim stablima kontrole.

Istraživanja su obavljena sa sortom jabuke Golden Delicious (Malus x domestica Borkh), koja je cijepljena na slabo bujnu podlogu M 9, i uzgajana u gustom sklopu (3000 stabala/ha). U pokusu je istraživan utjecaj fertirigacije dušikom u dozama od 45, 60 i 120 kg/ha, natapanja bez gnojidbe, te kontrole (bez natapanja i uporabe gnojiva) na rast i rodnost jabuke Golden Delicious. Tretmani su primjenjivani u dva vremenska intervala tijekom vegetacije: od 1. svibnja do 20. lipnja, te od 1. svibnja do 1. kolovoza. Pokus je trajao osam godina počevši od druge godine poslije sadnje (1992-1999.). Istraživanjima nije utvrđen konzistentan utjecaj primijenjenih tretmana na dinamiku rodnosti, kumulativni prirod i učinkovitost rodnosti. Najveći kumulativni prirod, uz relativno nizak indeks alternativne rodnosti, postignut je uz fertirigaciju sa 60 kg N/ha, kada je ona primjenjivana u razdoblju od 1. svibnja do 20. lipnja. U svim varijantama pokusa dinamika rodnosti slijedila je sličan trend uz jače izraženu tendenciju alternativne rodnosti u varijantama bez fertirigacije s dušikom, a puna rodnost postignuta je u petoj godini nakon sadnje., The study was conducted in a ‘Golden Delicious’/M9 orchard (3000 trees/ha) to investigate the effects of fertigation with N at 45, 60 and 120 kg/ha, and irrigation without fertilizers on the growth and productivity of the crop. Treatment durations were from 1 May to 20 June, and from 1 May to 1 August. Treatments began during the 2nd year after planting, and lasted eight years (1992-1999). Fertigation with N at different rates showed no consistent effect on the dynamic of cropping, cumulative yield and yield efficiency. The tendency to biennial bearing in the treatment with N-fertigation was generally low and markedly higher in the treatment without fertigation. The highest cumulative yield, with low index of alternate bearing was obtained in the treatment receiving 60 kg N/ha from 1 May to 20 June. The yield was obtained increasing dynamic followed the similar trend in all treatments, and full productivity was achieved in the fifth year after planting.

Utjecaj folijarne aplikacije nekih hraniva, sa ili bez fertirigacije s dušikom, u uspredbi s klasičnom gnojidbom s dušikom, na vegetativni rast, rodnost, te sadržaj mineralnih elemenata u plodovima, istraživan je sa sortom Golden Delicious, cijepljenom na podlozi M9, tijekom 2000-2002. Istraživanja su obavljena u dva subpokusa: u prvom počevši s dvogodišnjim, a u drugom s trogodišnjim voćkama. U obadva pokusa voćke su uzgajane kao super vreteno (razmak sadnje 3.2 x 0.7m). Rezultati istraživanja ukazuju na veće značenje opterećenja rodom, a relativno mali učinak folijarne gnojidbe na rast, rodnost i sadržaj mineralnih elemenata u plodovima u godinama ulaska u produktivnu dob. Kada su stabla bila prikladno opterećena rodom, sadržaj i odnosi N/Ca, K/Ca i (Mg + K)/Ca bili su u granicama koje omogućuju uspješno čuvanje u hladnjači. Nasuprot tomu, u stabala s niskim opterećenjem, niti primjena folijarne gnojidbe nije pridonijela poboljšanju sadržaja mineralnih elmenata i plodovi su bili neprikladni za duže čuvanje u hladnjači., The effect of foliar application of some nutrients and fertigation in comparison with broadcast nitrogen fertilization on growth, yield and mineral fruit composition of young apple ‘Golden Delicious’, grafted on M9 rootstock was investigated in years 2000-2002. Two orchard experiments were established, one with 2-year and the other with 3-year old trees, grown at a spacing of 3.2 x 0.7 m and trained to super spindle. The results showed low beneficial effect of applied treatments, and relatively high effect of crop load on growth, yield and fruit mineral content. Ratios of N/Ca, K/Ca and (Mg + K)/Ca in fruits indicated good storage quality as related to normal crop load. Contrary to that, when treatments were applied on trees with inadequate crop load, no beneficial effect occurred and fruits showed low storage life. This result illustrates the important balance between vegetative growth and fruit load that occurs during tree establishment.

Istraživana je mogućnost pospješivanja razvoja lateralnih izbojaka u rasadniku na sadnicama jabuke sorti Jonagold i Golden Delicious. U rasadniku su sadnice, kada su postigle visinu oko 75 cm, podvrgnute sljedećim zahvatima: uklanjanje vršnih nerazvi-jenih listića, uklanjanje vršnih nerazvijenih listića u kombinaciji s tretiranjem s 0, 25% Paturylom 10 WSC, tretiranje s 0, 25% Paturylom 10 WSC (2 puta u razmaku od 24 dana), tretiranje s 20% Promalinom (GA4+7) dva puta u razmaku od 9 dana. Uklanjanje nerazvijenih listića povoljno je utjecalo na kut grananja, ali nije stimuliralo razgranjavanje sadnica. Tretiranje Paturylom negativno je utjecalo na visinu sadnica, ali je broj lateralnih izbojaka bio veći uz povoljan kut grananja. Uklanjanje nerazvijenih listića u kombinaciji s tretiranjem s Paturylom najpovoljnije se odrazilo na razgranjavanje sadnica. Promalin je povoljno utjecao na razgranjavanje, ali je kut grananja bio nepovoljniji nego u ostalim tretmanima.

Istraživanja su obavljena sa sortom jabuke Idared (Malus x domestica Borkh), koja je cijepljena na slabo bujnu podlogu M 9, i uzgajana u gustom sklopu (3000 stabala/ha). U pokusu je bilo pet tretmana (fertirigacija s 45 kg N/ha, 60 kg N/ha, 120 kg N/ha, natapanje bez gnojidbe i kontrola – bez natapanja i uporabe gnojiva), u dvije varijante (tretmani za vrijeme vegetacije: od 1. svibnja do 20. lipnja – varijanta A, i od 1. svibnja do 1. kolovoza – varijanta B). Pokus je trajao sedam godina počevši od druge godine poslije sadnje (1992-1998.). Istraživanjima nije utvrđen konzistentan utjecaj primijenjenih tretmana na dinamiku rodnosti, kumulativan prirod i učinkovitost rodnosti. U svim varijantama pokusa dinamika rodnosti slijedila je sličan trend uz slabo izraženu tendenciju alternativnoj rodnosti, a puna rodnost postignuta je u petoj godini nakon sadnje. Dobiveni rezultati istraživanja potvrđuju da je sorta Idared vrlo prikladna za intenzivan uzgoj u sustavu gustog sklopa., The trial was conducted in an ‘Idared’/M9 orchard (3000 trees/ha), designed as split-block comprising five treatments (fertigation with 45 kg N/ha, 60 kg N/ha, 120 kg N/ha, irrigation without fertilisers, and control - without irrigation and without fertilisers), and two timing variants (treatments during vegetation period from 1 May to 20 June - variant A, and treatments from 1 May to 1 August – variant B). The treatments began in the second year after planting and lasted seven years (1992-1998). Fertigation with different amounts of nitrogen had no consistent effect on the dynamic of cropping, cumulative yield and regularity of bearing. Tendency to biennial bearing was low, dynamic of yield increasing followed the same trend in all treatments, and full productivity was achieved in the fifth year after planting. This means that ‘Idared’ is a very suitable apple cultivar for growing in the system of high density planting.

The trial was conducted in a `Elstar'/M9 orchard (2500 trees/ha) and the experiment was designed as a split-block comprising five treatments (fertigation with 45 kg·ha-1 N, 60 kg·ha-1 N, 120 kg·ha-1 N, irrigation without fertilizers, and control—without irrigation and without fertilizers), and two timing variants (treatments during vegetation period from 1 May to 20 June—variant A, and treatments from 1 May to 1 Aug.—variant B). The treatments were imposed beginning in the second year after planting and lasted five years. Fertigation with different amounts of nitrogen had no consistent effect on tree growth, cumulative yield and yield efficiency, however, treatments had a significant influence on regularity of bearing. The index of alternate bearing varied with treatment, but in both variant was significantly higher in control and in treatment with irrigation without application of fertilizer. These results demonstrated that the natural tendency of `Elstar' to alternate bearing could be broken by the different rates of nitrogen applied by fertigation.

Istraživanja su obavljena u pokusnom voćnjaku Sadjarskog centra Maribor - Gačnik sa sortama Elstar i Jonagold (2500 stabala/ha), te Idared i Golden Delicious (3000 stabala/ha), cijepljenim na podlozi M9, uzgajanih u obliku vitkog vretena. Pokus je trajao tri godine (3-5. godina poslije sadnje). Pokus je za svaku sortu postavljen u pet tretmana (fertirigacija s 45 kg N/ha, 120 kg N/ha, 60 kg N/ha, natapanje bez gnojiva i kontrola - bez gnojiva i vode), u dvije varijante (tretmani tjekom vegetacije od 1.svibnja do 20. lipnja &#8211 ; ; varijanta A i tretmani od 1. svibnja do 1. kolovoza &#8211 ; ; varijanta B). Neovisno o primjenim tretmanima, tjekom dvije godine prirast debla bio je približno jednak kod sorti Idared i Golden Delicious, nešto veći kod sorte Jonagold, a najveći kod sorte Elstar. Najveća prosječna dužina jednogodišnjih izbojaka utvrđena je kod sorte Elstar, dok kod sorte Jonagold, koja po svojim osobinama spada u bujne sorte, prosječna dužina jednogodišnjih izbojaka nije bila bitno veća nego kod sorte Idared i Golden Delicious. U odnosu na ostale sorte, kod sorte Elstar utvrđen je značajno veći broj jednogodišnjih izbojaka, a najmanji kod sorte Idared. Istraživanja su pokazala da fertirigacija jabuke pojedinih sorti odražava učinke različitog intenziteta na vegetativni rast. Dobiveni podaci potvrđuju poznatu činjenicu, da su sorte Jonagold i Elstar bujnije od Idareda i Golden Deliciousa.

Canopies of `Fuji' apple trees, grafted on M.9 rootstock, planted in 1998 on two orchard sites at 2.8 × 0.7 m and trained as super spindles, were subdivided in Spring 2003 into upper and lower parts. In each part, the number of fruits, yield per tree, external (fruit size classes, and fruit coloring), and internal (total sugar content, titratable acid content, and flesh firmness) fruit quality attributes were determined. The orchard site parameters affected growth, yield, and fruit quality in different ways. The less suitable orchard site had less growth, lower yield per tree, and a lower percentage of first class fruits, but most fruits had good color (86% in top and 75% in lower part of canopy). The favorable orchard site produced higher growth and yield, and a higher percentage of first class fruits, but fruits had poorer color. In the lower part of the canopy, fruits were of a good size, but had poor color. Fruits of the best quality were obtained from the top part of the tree.

The ability of various treatments to induce sylleptic shoot development of nursery trees of the apple `Jonagold' and `Golden Delicious' on root-stock M.9 was investigated. The leader management techniques were: removal of sub-terminal leaves, removal of sub-terminal leaves with application of 0.25% Paturyl 10 WSC (6-benzyladenine), and treatment with 0.25% Paturyl 10 WSC (two times at 24 days interval); application of 20% Promalin (GA4+7) two times in 9 days interval; and control; starting when scion length was 75 cm. Removal of sub-terminal leaves increased total branch length, but not stimulated the lateral branching. Treatments with Paturyl resulted in the lower tree height, in the higher number of branches, and in the greater branch length. Removal of sub-terminal leaves in combination with Paturyl increased the lateral shoot number even more than treatment only with Paturyl. Promalin increased branching, but had little influence on the total branch length. In addition, Promalin decreased branch crotch angles.

In central Europe there are many backyard fruit growers who receive no proper education about fruit tree care. Their knowledge is mostly based on various handbooks and learning through trial and error. Such learning is slow and can even result in damage to the tree. To shorten the learning time, a new interactive teaching tool EduAPPLE has been developed based on the basic laws of apple tree (Malus ×domestica) growth and training. Pruning, weighting, tying, and spreading can be interactively practiced over and over again without any danger to the actual trees. Training responses are immediately seen and are analogous to those of real trees. They are not only predetermined by a set of rules, but also calculated based on the changes the actions cause to the light interception of the tree. EduAPPLE enables high-quality views of trees and their light interception from all angles in real time and is designed for education regarding free-standing apple tree training (spindle). It can, therefore, be used in schools, universities, and other educational organizations, as well as by tree growers, including the large number of growers having only a few fruit trees.