Title: GROWTH AND YIELD CHARACTERISTICS OF NEW APPLE CULTIVARS

Authors: Dragan Milatović, Dejan Đurović

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Abstract: Ten relatively new apple cultivars: ‘Royal Gala’, ‘Gala Must’, ‘Elista’, ‘Morren’s Jonagored’, ‘Pilot’, ‘Pinova’, ‘Delbard Jubilé’, ‘Braeburn’, ‘Fuji Naga-fu 2’, and ‘Fuji Naga-fu 6’ were studied in the region of Central Serbia during the five-year period (2004-2008). Control cultivar for comparison was ‘Idared’, as the most grown apple cultivar in Serbia. The aim of this study was to assay the growth and yield characteristics of new apple cultivars grown in a dense planting. The experimental orchard was planted in the spring of 2002 in the village of Krćevac (municipality Topola). The rootstock was M9, training system was slender spindle and tree spacing was 3.6 m x 1 m. Following indicators of tree vigour and productivity were studied: yield, trunk cross-sectional area, yield efficiency, biennial bearing index, and fruit weight. The highest average yield of 15.5 kg per tree was achieved by cultivar ‘Pinova’ and it was significantly higher than in control cultivar (‘Idared’). The greatest vigour was expressed by cultivars ‘Delbard Jubilé’, ‘Elista’, ‘Fuji Naga-fu 2’, ‘Fuji Naga-fu 6’, and ‘Jonagored’, which had significantly larger trunk cross-sectional area compared to control. Significantly higher yield efficiency was found in cultivars ‘Pinova’ and ‘Royal Gala’. Cultivars ‘Delbard Jubilé’, ‘Fuji Nagafu 2’, ‘Fuji Naga-fu 6’, and ‘Elista’ showed strong tendency to biennial bearing. Fruit weight ranged from 143 g (‘Royal Gala’) to 207 g (‘Jonagored’). Six varieties (‘Elista’, ‘Royal Gala’, ‘Pinova’, ‘Gala Must’, ‘Braeburn’, and ‘Pilot’) had significantly lower fruit weight compared to control cultivar. To obtain satisfactory fruit size and ensure regular cropping it is necessary to apply fruit thinning. This operation is particularly important for cultivars that are prone to biennial bearing, as well as cultivars that tend to have smaller fruit size.

Key words: Malus domestica, yield, yield efficiency, biennial bearing index, fruit weight

Title: BIOLOGICAL PROPERTIES OF APPLE CULTIVARS ‘RAJKA’ AND ‘TOPAZ’ RESISTANT TO Venturia inaequalis (Cooke) Wint.

Authors: Milan Lukić, Slađana Marić

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Abstract: From the aspect of rational use of pesticides and environmental protection, growing cultivars resistant to pests and causal agents of the most serious diseases is one of the most recent trends in modern apple production. The paper presents the results of a three-year study on biological characters of scab resistant apple cultivars ‘Rajka’ and ‘Topaz’ which were grown under agro-environmental conditions of Čačak. In this study, ‘Rajka’ had earlier blooming time, greater abundance and ripened somewhat earlier than ‘Topaz’. Fruits of ‘Topaz’ were large, oblate. Both cultivars showed high cropping potential, although ‘Topaz’ had higher fruit quality and yield.

Key words: apple, cultivar, biological properties, Venturia inaequalis (Cooke) Wint.

Title: EFFICACY OF CHEMICAS CONTAINING 6-BENZYLADENINE IN APPLE FRUITS THINNING

Authors: Zoran Keserović, Biserka Milić, Nenad Magazin, Marko Dorić

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Abstract: The trials designed to examine the efficacy of fruit thinning chemicals in apple, containing 6-benzyladenine as an active matter were set up in 2011 growing season and included cultivars ‘Golden Delicious’ (clone ‘Reindres’), ‘Topred’, ‘Jonagold’ (clone ‘Decosta’) and ‘Idared’. The following treatments were applied: untreated control, Gerba 4LG in the rate of 2.5 ml/l, MaxCel 5.0 ml/l MaxCel 7.5 ml/l. Thinning chemicals were highly effective in ‘Golden Delicious’ in terms of reduced number of fruits per tree and fruit set and increased fruit weight. ‘Idared’ and 'Jonagold' had higher average fruit weight in all treatments compared to the control, although chemicals were not as effective in reducing fruit set. The lowest efficacy of the chemicals was observed in ‘Topred’ where phytotoxicity occurred resulting in fruit size stunting, probably due to root pruning. Inadequate air temperature during and after the treatments as well as diameter of the fruits are possible factors that affected efficacy of the chemicals.

Key words: apple, cultivar, 6-benzyladenine, thinning, fruit set, fruit weight

Title: HEAVY METALS CONTENT IN APPLE CULTIVAR ‘IDARED’ GROWN IN COMMERCIAL PLANTINGS OF THE ČAČAK REGION

Authors: Mira Milinković, Rade Miletić, Vera Raičević, Blažo Lalević

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Abstract: In the present paper we investigated contents of heavy metals (As, Pb, Cd and Hg) and health damaging substances (nitrates and nitrites) in fruits of apple ‘Idared’ grown on different localities in the Čačak region. The cultivar dominates local commercial apple plantings and is the leading apple cultivar produced for both export and domestic markets. Therefore, control of sanitary and health status of produced apple fruits is of key importance. Arsenic (As) content in apple fruits varies among localities, ranging from 0.0035 mg/kg to 0.0071 mg/kg, variation coefficient being from 4.51% to 36.82%. Lead (Pb) content ranged from 0.0035 mg/kg to 0.0807 mg/kg, its variation coefficient being 4.51–11.44%. Cadmium (Cd) and mercury (Hg) contents were within the range 0.00280.0059 mg/kg and 0.0058-0.0076 mg/kg, respectively, their variation coefficients varying by localities between 6.11% and 37.10% and 6.03% and 23.67%, respectively. Nitrates and nitrites content in all samples was below 3 mg/kg of fresh fruit weight. The established contents of heavy metals, nitrates and nitrites was considerably lower than prescribed by Regulation. The obtained results infer that the growing region above is very suitable for commercial apple production in the studied parameters.

Key words: apple, cultivar localities, heavy metals, nitrates and nitrites

Title: THE STUDY OF FERTILIZATION DEGREE IN PLUM CULTIVAR ‘POZNA PLAVA’ IN SELFAND OPEN POLLINATION VARIANTS

Authors: Milena Đorđević, Radosav Cerović, Sanja Radičević

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Abstract: Fertilization level in selfand open pollination variants in plum cultivar ‘Pozna Plava’ was examined by fluorescence microscopy, and involved determination of the fruit set and in vitro pollen germination. Quantitative parameters of pollen tubes growth in the style and ovary over a two-year period within four successive terms were determined. The results obtained reveal strong tendency of ‘Pozna Plava’ to be on the verge between partial self-compatible to self-compatible.

Key words: Prunus domestica L., pollination, pollen tubes growth, fruit set

Title: EVALUATION OF INTRODUCED EARLY SEASON APRICOT CULTIVARS IN THE REGION OF BELGRADE

Authors: Dragan Milatović, Dejan Đurović, Gordan Zec

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Abstract: Apricot cultivar assortment in Serbia is characterized by small number of cultivars and a short period of maturing. Most apricot fruits are harvested in the season of cultivar ‘Hungarian Best’ or at a short time (about ten days) afterwards. There is particularly a lack of early-maturing cultivars of high quality fruit. The aim of this study was the evaluation of 12 introduced apricot cultivars of early maturing time in order to recommend best of them for growing in Belgrade area. Study was carried out at the Experimental station ‘Radmilovac’ of the Faculty of Agriculture in Belgrade over a period of four years (2009-2012). The experimental orchard was established in 2007, the rootstock was Myrobalan seedling, and tree spacing was 4.5 x 3 m. Control cultivar for comparison was ‘Hungarian Best’ (‘Magyar Kajszi’), which is the most grown apricot cultivar in Serbia. Introduced cultivars began to flower one to three days before the ‘Hungarian Best’, with the exception of four cultivars (‘Lejuna’, ‘Sunglow’, ‘Vesna’, and ‘Veselka’), that began to flower at the same time as the control cultivar. Average maturing time was from June, 8 (‘Aurora’) to June, 20 (‘Tomcot’), or 25 to 13 days before the ‘Hungarian Best’. Compared with the control cultivar, significantly higher yield was achieved in four cultivars ‘Dunstan’, ‘Ninfa’, ‘Leskora’, and ‘Veselka’, while significantly larger fruit size was achieved in two cultivars: ‘Dunstan’ and ‘Strepet.’ Cultivars ‘Dunstan’ and ‘Tomcot’ are characterized by high content of soluble solids. Most of the introduced cultivars had better fruit appearance, while fruit quality was generally lower than in control cultivar. Among studied apricot cultivars, four of them were singled out as promising for growing in the region of Belgrade: ‘Aurora’, ‘Dunstan’, ‘Veselka’, and ‘Tomcot’.

Key words: Prunus armeniaca, time of flowering, time of maturing, yield, fruit quality

Title: STUDY OF CORRELATIONS AMONG SOME PARAMETERS OF FLOWERING BIOLOGY IN SWEET CHERRY CULTIVARS (Prunus avium L.)

Authors: Sanja Radičević, Radosav Cerović, Milena Đorđević

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Abstract: The paper presents three-year results of examination of characteristics of flowering phenophase and in vitro pollen germination in 23 sweet cherry cultivars, viz. ‘Asenova Rana’, ‘Bianca di Verona’, ‘Burlat’, ‘Čarna’, ‘Diana’, ‘Durone Nero I’, ‘Early Compact Van’, ‘Inge’, ‘Junskaja ranaja’, ‘Kordia’, ‘Lambert’, ‘Lapins’, ‘Margit’, ‘Merchant’, ‘Negre de Bistrita’, ‘Priusadebnaja’, ‘Stark Hardy Giant’, ‘Stella’, ‘Summit’, ‘Sunburst’, ‘Uriase de Bistrita’, ‘Vega’ and ‘Vista’. The cultivars were classified based on flowering time as early-flowering, mid-early flowering, mid-late flowering and late-flowering cultivars. Moderate negative correlation between flowering time and duration of phenophase of flowering was identified (r = -0.65) as well as moderate positive correlation between flowering time and in vitro pollen germination (r = 0.63).

Key words: sweet cherry, cultivar, flowering phenophase, in vitro pollen germination

Title: THE EFFICACY OF ACETAMIPRID (VOLLEY 20 SP) IN CONTROLLING Cacopsylla pyri L. POPULATIONS

Authors: Svetomir Stamenković, Pantelija Perić, Dejan Marčić, Drago Milošević

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Abstract: European pear sucker (Cacopsylla pyri L.) populations have reached high abundance in Serbia over the past 30 years, and the intensity of attack has become high on nearly all pear cultivars. Population abundance, intensity of attack and efficacy of acetamiprid in controlling the pest in the region of Čačak over the 2009-2011 period is shown in the paper. The pear sucker was found in high abundance in all pear commercial stands in the Čačak region over the examination period. Population abundance was evaluated as the number of eggs and larvae per young shoot, and the intensity of attack as the percent of shoots damaged. Acetamiprid showed a high efficacy at the hatching stage (90.2-96.1%), while its efficacy in combination with abamectin (Armada) reached 100%.

Key words: acetamiprid, Cacopsylla pyri L., intensity of attack, control

Title: A study of the effect of a new plant protection system against plum rust in biological fruit production

Authors: Anton Atanasov, Hristina Dinkova, Kalin Dragoyski, Diyan Georgiev, Anton Velichkov, Gergana Kirilova

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Abstract: A new plant protection system in biological fruit production has been field-tested and studied for efficacy in plum rust (Tranzschelia pruni-spinosae (Pers) Diet.) control. The system includes the botanical insecticides Trifolio S forte, NeemAzal, Tresar 480 CK, Dipel 50 WP and Madex, two preparations licensed for biological fruit production, Champion N WP and Funguran (77% cupric hydroxide), and sugar as an adjuvant. These substances were applied as mixtures in the doses as used in practice. Plum cultivar ‘Elena’ (late-ripening plum cultivar, harvested in the second part of September) planted at distance of 4 x 3 m was used in experiment. The outcome of the experiment was assessed in late August based on a five-grade infestation score system, with P = 0.05 and t = 2.77. The biological preparations achieved top scores: 15.0 ± 3,4% intact leafage (grade 0); 65 ± 3.3% in grade 1 and only 20 ± 3.1% in grade 2. The insecticidal treatment using Acarsin (paraffin oil), Champion (77% cupric hydroxide), Methyltopsin, Systane, Nurele D and Karate 2.5 EC yielded rust compromised leafage at grades 2, 3 and 4, whereas the whole control leafage was compromised at grade 4 (up to 50% damage) or grade 5 (over 50%).

Key words: Tranzschelia pruni-spinosae (Pers) Died, biopreparations, plum cv ‘Elena’