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Apple is one of the most cultivated fruit trees in the world. Consumers value high quality fruit, with desirable morphological characteristics, good aroma and taste. Given the popularity of red apple fruits, the need for its cultivation is growing. The aim of this research was to analyze the qualitative characteristics of 4 commercial apple cultivars (‘Gala’, ‘Red Delicous’, ‘Jonagold’ and ‘Golden Delicous’) and their clones (‘Schnico Red Gala’, ‘Scarlet Spur’, ‘Wilton’s’, ‘Red Jonaprince’ and ‘Reinders’). Research was carried out on the Radmilovac Experimental Site in a two-year period (2021 and 2022). The following morphological parameters were monitored: weight, height and width of the fruit, index of the fruit, length of the stalk, firmness of the fruit and coloration of the fruit. Also, biochemical parameters were measured: content of soluble solids, total titratable acidity and flavour index. Sensory analysis was performed by scoring fruit attractiveness, taste and aroma. Clones had higher degree of attractiveness due to intense red colour (‘Schnico Red Gala’, ‘Scarlet Spur’, ‘Wilton’s Red Jonaprince’) or reduction of rustiness (‘Reinders’), in comparison to commercial varieties.In some clones (‘Wilton’s Red Jonaprince’ and ‘Scarlet Spur’) fruit size was decreased in comparison to parent cultivar. ‘Wilton’s Red Jonaprince’ had the best parameters of biochemical quality –highest soluble solids, titratable acidity and flavor index among all analyzed genotypes. The decrease of quality (soluble solids, acidity and flavor index) is noticed in the clones ‘Scarlet Spur’ and ‘Reinders’. ‘Schnico Red Gala’ showed the highest increase of sensory properties in comparison to original cultivar (‘Gala’). Clone ‘Wilton’s Red Jonaprince’ showed the best overall biochemical quality and sensory traits in comparison to all analyzed genotypes.

Cherry production in Serbia is predominantly extensive and based almost entirely on seedling rootstocks Mazzard (Prunus avium L.) and Mahaleb (Prunus mahaleb L.). The commercial intensive orchard on the clonal sour cherry rootstock ‘Oblačinska’ (Prunus cerasus L.) was established in 2013 with a planting distance of 4.0 m × 2.5 m. Six sweet cherry cultivars were studied: ‘Burlat’, ‘Valery Chkalov’, ‘Carmen’, ‘Summit’, ‘Sunburst’, and ‘Germersdorfer Grosse Kirsche’. During a tree-year period (2017-2019), the following characteristics were studied: flowering and ripening time, vigor (trunk cross-sectional area), yield, yield efficiency, and fruit quality. The average flowering time was in the first decade of April. The ripening period ranged from May 20 to June 13. The cultivar ‘Summitʼ showed significantly higher vigor then other cultivars. The lowest average yield per tree was recorded for the cultivar ‘Valery Chkalovʼ (4.4 kg) and the highest for the cultivar ‘Summitʼ (13.3 kg). The cultivar ‘Summitʼ had a statistically significantly higher yield compared to the other cultivars. The highest yield efficiency was obtained for the cultivar ‘Summitʼ (0.14 kg/cm2). The average fruit weight was lowest in the cultivar ‘Burlatʼ (7.1 g), and was statistically significantly lower compared to the other cultivars. The highest average fruit weight (11.0 g) was found in the cultivar ‘Carmenʼ. Based on the results obtained, the cultivars ‘Summitʼ and ‘Carmenʼ can be recommended for cultivation on the sour cherry rootstock ‘Oblačinska’.

Fruit set and yield potential were studied in 15 genotypes of vineyard peach of late maturity (from middle to the end of September) during a three-year period (2012-2014). The study was carried out at the Experimental Station Radmilovac of the Faculty of Agriculture in Belgrade. Genotypes were evaluated for: Initial and final fruit set, fruit weight, number of fruits m-1 of shoot length and yield m-1 of shoot length. Initial fruit set varied from 36.0% (genotype IV/16) to 67.0% (genotype IV/14), and final fruit set from 24.9% (genotype IV/13) to 51.2% (genotype IV/14). Fruit weight ranged from 40.1 g (genotype II/24) to 78.2 g (genotype II/17). Highest number of fruits m-1 of shoot length was recorded at genotype II/17 (21.3) and the lowest at genotype II/31 (9.6). Yield m-1 of shoot length varied from 0.5 kg (genotypes II/13 and II/24) to 1.4 kg (genotype IV/18). Among studied vineyard peach genotypes, three genotypes (II/17, IV/17 and IV/18) can be recommended as promising related to yield potential, or as starting material for new peach cultivars of late maturity in further breeding work.

Phenological characteristics and yield potential in eight promising peach hybrids from selection based on fruit quality were studied in this paper. The hybrids flowered from late March to mid-April, and fruit ripened from late August to late September. The FS3, FS4, and FS7 hybrids had the highest density of flower buds. The initial fruit set was quite high (73.9%) and the final fruit set was much lower (32.2%). Fruit weight ranged from 129.8 g (FS4 hybrid) to 178.1 g (FS7 hybrid). The FS3 and FS7 hybrids had the highest yield per 1 m of shoot length (3.5 kg), and the FS2 hybrid had the highest yield per tree (25.3 kg) and the highest yield efficiency (0.30 kg cm-2). The FS2, FS3, and FS7 hybrids stood out based on yield potential. They are good candidates for release as new high-yielding peach cultivars or for use in further breeding efforts.

This paper presents the results of the two-year (2015-2016) research of changes in fruit quality of quince fruits during cold storage. The investigations were conducted in eight quince cultivars: ‘Vranjska’, ‘Leskovacka’, ‘Morava’, ‘Pazardzijska’, ‘Hemus’, ‘Asenica’, ‘Portugal’ and ‘Triumph’. The fruits of the quince were kept in cold storage with normal atmosphere for five months, from October 20 to March 20, in temperature 0-2°C and air humidity 80%. After this period, changes in fruit quality were determined. The highest fruit weight loss was found in the cultivar ‘Pazardzijska’ (16.33%), and the lowest in ‘Asenica’ and ‘Morava’ (6.66 and 7.98%, respectively). Also, in ‘Pazardzijska’, the biggest soluble solids content (SSC) decrease (14.70%) was determined, while the smallest SSC decrease was determined in ‘Leskovacka’, ‘Morava’ and ‘Portugal’ (below 4%). The total acid content decrease varied from 33.05% in ‘Leskovacka’ to 63.75% in ‘Pazardzijska’. The losses in fruit firmness were smallest in ‘Pazardzijska’, and the largest in ‘Portugal’. The occurrence of flesh browning was lowest in ‘Asenica’ and ‘Hemus’, and largest in ‘Pazardzijska’. Of the investigated quince cultivars, the best results during the cold storage were determined in ‘Leskovacka’, ‘Morava’ and ‘Asenica’, and the worst in ‘Pazardzijska’.

This study was realized in order to evaluate usability of isoenzymes in selection of low vigour cherry genotypes. The correlation of isoenzyme profiles with plant/tree vigour of 20 genotypes belonging to the genus Prunus, subgenus Cerasus as well as to four commercial rootstocks (Colt, Gisela 5, Gisela 6 and MaxMa 14) was investigated in this study. For this purpose, isoenzyme bands were identified by polyacrylamide gel electrophoresis (PAGE) for eight systems: alcohol dehydrogenase (ADH), formate dehydrogenase (FDH), glutamate dehydrogenase (GDH), isocitrate dehydrogenaze (IDH), malate dehydrogenase (MDH), phosphogluconate dehydrogenase (PGD), shikimate dehydrogenase (SDH) and peroxidase (PRX). Inner bark of one-year-old shoots, in dormant stage was used for protein extraction. Cluster analysis was used to construct dendrogram for the classification of the cherry genotypes based on vigour traits and polymorphism of isoenzymes. The results showed that isoenzyme activity could be used in the selection of low vigour cherry genotypes and rootstock for high density orchards.

Seventy-five vineyard peach [Priam persica (LJ Batsch] accessions, obtained by seed propagation and originating from different regions of Serbia, were characterized using a set of 39 agro-morphological traits. The evaluation was carried out over a 3-year period in a vineyard peach collection situated at the Radmilovac Experimental Station, owned by the Faculty of Agriculture, Belgrade University. To investigate diversity, descriptive statistics and multivariate analyses were used. Most studied traits showed high variability. The variability of descriptive traits was highly pronounced for fruit ground and flesh colour; regarding metric traits, the highest variation was recorded for trunk circumference, petal width, flower density, fruit set, fruit weight, sweetness index, fruit taste and fruit flavour. According to PCA, traits with high discriminating power were those related to flower type, colour and size, fruit size and presence of over colour, tree height, ripening time and fruit taste. The cluster analysis grouped accessions into three main clusters and a few sub-clusters. Agronomically important traits allowed a clear separation between the clusters, while morphological traits had almost no impact on this. This study provided information that is important for assessing the biodiversity of vineyard peach accessions, to develop guidelines useful for the description, classification and conservation of valuable local germplasm. Moreover, the phenotypic variability in the vineyard peach collection was found to be very high, suggesting there is extensive genetic diversity available for peach cultivar and rootstock breeding programs.

In this research, morphological characterization of vineyard peach collection was conducted. In 78 accessions thirty qualitative traits of tree, flower, leaf, fruit and stone were analysed by using UPOV and ECPGR descriptors. Most of the studied traits showed a high degree of variability. The lowest variability obtained for the leaf traits, and highest for skin and flesh colour. Not only were the accessions sorted into a large number of categories by the most of their properties, but also there was a significant level of variability in the collection, reflecting in the fact that the traits were recombinant in a different way. Principal component analysis (PCA) and a dendrogram were performed to determine relationships among accessions and to obtain information on the usefulness of those characters for the discrimination. The PCA revealed that the first 4 principal components were able to represent 43.1% of total variance. Traits with high discriminating values comprised internal and external fruit colour, flower type and colour, flower bud density and stone shape. The cluster analysis showed that the accessions were placed in three main clusters. The greatest impact on the separation in clusters had fruit over colour and extent of fruit over colour. Moreover, the collection can also comprise some accessions with the preferred recombination of properties that might be interesting for further studies in breeding.

This study was carried out in order to determine the rootstock effect on content of oil and most abundant fatty acids (oleic acid and linoleic acid), oleic acid/linoleic acid ratio, total phenolic content (TPC) and radical-scavenging activity (RSA) of almond kernels. The experimental orchard was established in 2006 in Surduk (North Serbia). Cultivars 'Troito', 'Marcona' and 'Texas' were budded (grafted) on myrabalan plum seedlings and 'GF 677'. Results revealed significant influence of rootstock on evaluated characteristics. Except content of oleic acid and oleic acid/linoleic acid ratio all other parameters had higher values when cultivars were grafted onto myrabalan plum. As expected, significant differences were also determined among studied cultivars. Except content of linoleic acid, for all other parameters the lowest values were found in 'Marcona', while highest for 'Texas'. Obtained results can be used for improving of almond quality in agroecological conditions of Serbia.

Vitality of pollen, in vitro pollen germination and pollen tube growth (pollen tube length and pollen tube growth rate) were investigated in Oblacinska sour cherry in order to determine the differences between clones which have divergent yielding potential. For this purpose two 'Oblacinska' sour cherry clones with high fruit set and high yields (II/2, III/9) and two with low fruit set and low-yielding (XI/3 and XIII/1) were used in this study. Pollen germination was done on artificial medium containing 14% sucrose and 0.3% agar-agar at room temperature (23 degrees C). Pollen tube growth was stopped with a drop of 40% formaldehyde, 1, 3, 6, 12 and 24 h after contact with the medium. The maximum percentage of germination ranged from 13.01% (clone II/2, after 1 h) to 54.19% (clone III/9, after 24 h). Pollen tube length varied from 64.84 mu m (clone XIII/1, after 1 h) to gt 1,100 mu m (clones II/2 and III/9, after 24 h). Pollen growth rate was quite high (up to 1.71 mu m min(-1)) after 6 h of germination, but rather decreasing until 24 h of germination (0.56. 0.83 mu m min(-1)). The dynamics of in vitro pollen tubes growth among the clones were quite different, especially after 12 h and 24 h of germination. Clones that are singled out as fruitful (II/2 and III/9) gave much better results regarding pollen germination and pollen tube growth in comparison to clones which were characterized by low fruit set and yields (XI/3 and XIII/1).

This research was conducted to compare biological and pomological characteristics of 15 almond selections from Serbia with cultivars 'Marcona', 'Texas' and 'Troito'. The evaluation of bloom and harvest times, yields and pomological characteristics of nuts and kernels was done during the five year period (2010-2014) in Surduk (northern Serbia). The earliest bloom time was observed in the selections '15/03' and '23/03' (March 26) and the latest in the cultivar 'Texas' (April 5). The average harvest time was the last week of August or the first week of September. The highest yield tree(-1) was recorded for the cultivars 'Marcona' and 'Texas'. Fruit weight ranged from 3.8 to 6.2 g, kernel weight from 0.6 to 1.3 g, and kernel percentage from 13.4 to 32.3%. On the basis of all observed characteristics, the selections '12/03', '24/03', '25/03', '28/03' and the cultivars 'Troito' and 'Texas' can be recommended for growing in the region of Surduk and considered for growing in other parts of Serbia.

The characteristics of growth and yield of seven quince cultivars: 'Vranjska', 'Morava', 'Pazardzijska', 'Hemus', 'Asenica', 'Portugal' and 'Triumph' were studied in the Belgrade region during the four-year period (2010-2013) in comparison with the cultivar 'Leskovacka', which was used as the standard. The tested cultivars were significantly different in terms of vigour and productivity. The lowest vigour was shown by 'Leskovacka' cultivar and the highest by 'Portugal' and 'Morava'. The highest yield tree(-1) and unit area(-1) was found in 'Triumph' and 'Portugal', and the lowest in standard cultivar. With the exception of 'Vranjska' and 'Pazardzijska', the other cultivars had significantly higher yields tree(-1) and unit area(-1) than the standard cultivar. Although 'Leskovacka' had the lowest yields tree(-1) and unit area(-1), due to low vigour, it had higher yield efficiency than most of the studied cultivars. Based on the cropping potential, for commercial growing 'Triumph' and 'Portugal' can be recommended. Also, these cultivars are good starting material in quince breeding and creating new cultivars of high cropping potential.

Istraživanjima u okviru ove doktorske disertacije na osnovu većeg broja kvalitativnih i kvantitativnih osobina izvršena je morfološko-anatomska karakterizacija i evaluacija 75 genotipova vinogradarske breskve u okviru kolekcije oglednog dobra “Radmilovac”, Poljoprivrednog fakulteta u Beogradu. Istraživanja su obuhvatila i analizu varijabilnosti i korelacione povezanosti osobina, a sve u cilju izdvajanja perspektivnih genotipova sa akcentom na stonu potrošnju. Karakteristike fenofaze cvetanja i sazrevanja, anatomske karakteristike lista, broj zametnutih i ubranih plodova, biohemijski sastav ploda i organoleptička ocena svežih plodova utvrđeni su metodama standardnim za ovu vrstu istraživanja, dok su morfološke karakteristike pojedinih organa utvrđene merenjem ili ocenjivanjem pomoću UPOV i ECPGR deskriptora za breskvu. Ispitivana kolekcija vinogradarske breskve pokazala se kao značajan genofond sa visokim stepenom varijabilnosti osobina. Među ispitivanim genotipovima ispoljile su se veoma značajne razlike u pogledu vremena cvetanja i sazrevanja, bujnosti stabla, rodnosti, krupnoće i kvaliteta plodova. U ispitivanoj kolekciji genetička varijansa je dominirala u ukupnoj varijabilnosti vremena sazrevanja plodova kao i osobina stabla (visina stabla, visina krune, prečnik krune, visina debla, obim debla), grančice (dužina i debljina grančice), lista (dužina i širina liske, indeks oblika liske, površina liske), cveta (prečnik cveta, dužina i širina kruničnih listića, indeks oblika kruničnih listića, broj prašnika, dužina i širina antere, dužina tučka) i ploda (masa koštice, sadržaj rastvorljive suve materije, sadržaj ukupnih kiselina i ukupnih šećera, izgled ploda, ukus ploda i ukupna senzorna ocena). To znači da su ove osobine strogo ili u velikoj meri pod kontrolom genotipa i da kao takve predstavljaju merodavni prikaz ispitivane kolekcije, na osnovu kojih se može sa većom pouzdanošću vršiti dalja selekcija sa ciljem povećanja rodnosti i poboljšanja kvaliteta ploda..., The research for this doctoral dissertation was based on a large number of qualitative and quantitative traits of the vineyard peach and it comprised morphological and anatomical characterization and evaluation of 75 vineyard peach genotypes within a collection of the “Radmilovac” Experimental Station of the Belgrade Faculty of Agriculture. The research also comprised the analysis of variability and correlation of traits in order to select prominent genotypes, particularly genotypes suitable for fresh consumption. Flowering and maturity traits, anatomic traits of peach leaves, fruit set and number of harvested fruits, biochemical composition and an organoleptic evaluation of fresh fruits were determined with standard methods for this type of research, whereas morphological traits of certain organs were determined after measuring or evaluation with UPOV and ECPGR descriptors for peach. The studied collection of the vineyard peach was proved to be a significant genepool with high variability of traits. Among the studied genotypes there were very significant differences in time of flowering and maturity, tree vigour, yielding, fruit size and quality. The genetic variance dominated the total variability of fruit maturity time, as well as tree traits (tree height, canopy height, canopy diameter, trunk height, trunk volume), traits of shoot (shoot length and thickness), leaf (leaf length and width, shape index, leaf area), flower (flower diameter, petal length and width, petal shape index, number of stamens, anther length and width, pistil length) and traits of fruit (stone weight, soluble dry matter content, total acids and total sugars, fruit appearance, taste and an overall sensory mark). It means that these traits are fully or to a large extent controlled by genotype. Hence they give a reliable overview of the collection, based on which further selection for better yields and better quality can be done more accurately...

The results of two-year research (2011-2012) of the most important morphological characteristics of 1-year-old shoots in eight peach hybrids obtained from a crossing combination Flaminia x Hale Tardiva Spadoni were shown in this paper. The following characteristics were studied in tested hybrids: length and diameter of shoots, internode length, number of flowers and vegetative buds per shoot, ratio of flower to vegetative buds, number of flower buds per node and 1-m length of a shoot. The properties of sylleptic shoots on one-year-old shoots have also been studied. The significant differences were determined among the hybrids for parameters such as the diameter of shoots, internode length, number of flower and vegetative buds per shoot. Hybrids FH1 and FH6 were characterized by the highest density of flower buds, so that they are singled out as potentially the most yielding. These hybrids may be of interest for growing in areas where there is a risk of frost and in the domain of breeding when creating new peach cultivars of high yield potential., U ovom radu prikazani su rezultati dvogodišnjih istraživanja (2011­2012) najvažnijih morfoloških osobina mešovitih rodnih grančica kod osam hibrida breskve dobijenih iz kombinacije ukrštanja Flaminia x Hale Tardiva Spadoni. Kod ispitivanih hibrida proučavane su sledeće osobine: dužina i prečnik grančica, dužina internodija, broj cvetnih i vegetativnih pupoljka po grančici, odnos cvetnih i vegetativnih pupoljaka, broj cvetnih pupoljaka po nodusu i 1 m dužine grančice. Takođe su proučavane i osobine prevremenih grančica koje se nalaze na mešovitim rodnim grančicama. Za parametre kao što su prečnik grančice, dužina internodija, broj cvetnih i vegetativnih pupoljaka na grančici utvrđene su značajne razlike između ispitivanih hibrida. Hibridi FH1 i FH6 su se odlikovali najvećom gustinom cvetnih pupoljaka, tako da su oni izdvojeni kao potencijalno najrodniji. Ovi hibridi mogu biti interesantni za gajenje u područjima gde postoji opasnost od pojave mrazeva i u oplemenjivanju prilikom stvaranja novih sorti breskve visokog rodnog potencijala.

Ground raw kernels of almond genotypes were selected in northern Serbia, analysed for oil and crude protein content and compared with commercial cultivars 'Troito', 'Texas' and 'Marcona'. The samples were collected in an experimental orchard in Surduk locality. Oil content was determined by using NMR (Nuclear Magnetic Resonance) analyser, while protein content was determined by using the Kjeldahl method. The results showed a significant variation between the genotypes and the cultivars. The selections had oil content ranging from 47.27 to 53.61%, while oil content in the cultivars varied from 52.33 to 55.64%. The lowest crude protein content was 19.85% (01/03) and the highest was 29.18% (29/03). The obtained values indicate that the selected genotypes (with the exception of B/04) had less oil, while the 12 out of the 15 selected genotypes were richer in proteins compared with the commercial cultivars. The most interesting genotype was 24/03, having a high quality of kernel (51.33% of oil and 26.12% of crude proteins).

This study was initiated to determine morphological and pomological traits, together with chemical compounds of kernels from 19 almond genotypes selected in the spontaneous seedling population in northern Serbia. The lowest variation was obtained for dry matter (CV=0.5%) and the highest for kernel weight (CV=18.4%). The overall mean values of pomological traits, contents of crude protein and mineral matter, showed significant differences between the genotypes. Genotype 25/03 had the lowest (0.69 g), whilst 28/03 had the highest kernel weight (1.29 g). The kernel/nut ratio ranged from 12.4 to 33.5%. The percentage of oil varied from 45.82 to 56.14% and most genotypes showed a high level of crude protein that varied from 20.94 to 26.85%. The most interesting for further studies were genotypes with kernel over 1 g: '29/03', '16/03', '28/03', '1/03', 'B/04', then genotypes '10/03', '11/03', and '17/03' with high kernel oil content (over 55%), as well as genotypes '18/03', '19/03', '22/03', having crude protein content of more than 25%.