Nebojša Milošević

Morphogenic variability of some autochthonous plum cultivars in western Serbia

A study conducted over a period of two years in a Western Serbian valley included in situ identification of autochthonous plum cultivars. Observation and recording of their phenological and pomological traits were performed using IBPGR and UPOV methodologies. Fifteen cultivars derived from Prunus domestica L. and two cultivars derived from P. insititia L. were identified. Flowering started between 24 March and 7 April and fruit ripening between 12 July (Petrovaca) and 16 September (Trnovaca). Fruit weight ranged from 6.79± 0.018 to 36.62± 0.251 g and stone weight from 0.14± 0.002 to 1.95± 0.023 g. The cultivars were classified as being extremely small in terms of fruit size. Rounded fruit shape and light-yellow ground colour were dominant. Skin colour ranged from amber to black. Yellow green was a dominant flesh colour and medium flesh firmness predominated. The fruits of the above cultivars could be processed, particularly into plum brandy, or they could be used fresh or dried. The selected plum cultivars can be used both in breeding programmes and as rootstocks as well as in further disease-related systematic studies under field and laboratory conditions.

Effect of tree conduce on the precocity, yield and fruit quality in apricot on acidic soil

The experiment was carried out in the experimental orchard in Prislonica near Cacak (Western Serbia) on poor and acidic soil in 2008 and 2009 (second and third year after planting) to determine the effects of Mirobalan rootstock and Blackthorn interstocks with Open vase and Central leader tree conduce system on the length of shoot (LS), trunk cross-sectional area (TCSA), yield (Y), yield efficiency (YE), fruit weight (FW), soluble solids content (SS), titratable acidity (TA) and soluble solids/titratable acidity ratio or ripening index (SS/TA = RI). In the trial there were 5 trees from each apricot rootstock-cultivar and rootstock-interstock-cultivar combination in four replications. The analysis of variance was done in a completely randomized design. The treatment means were compared using LSD test at p < 0.05. Based on the results of this work, the Myrobalan rootstock with Open vase tree conduce induced a high vigorous of apricot trees and higher fruit weight. The Blackthorn interstock with Central leader tree conduce induced a less vigorous tree, higher yield and yield efficiency, and may be better suited for high-density plantings. Also, this interstock showed the higher SS/TA ratio when compared with Myrobalan rootstock. Other fruit quality traits, such as soluble solids content and titratable acidity were similar and respectable in both variant under poor and acidic soil conditions.

Fruit Quality Attributes of Sour Cherry Cultivars

The aim of this study is the evaluation of two sour cherry cultivars (“Oblacinska”, “Cigancica”) grown at Cacak (Western Serbia) by determining main physical properties such as fruit linear dimensions, arithmetic and geometric mean diameter, fruit volume, sphericity, surface area, and aspect ratio at the commercial stage. Also, some attributes related to fruit quality (fruit weight, soluble solids, total acidity, ripening index, and pH juice) were evaluated at different ripening stages. “Oblacinska” shows better physical properties, except aspect ratio, when compared with “Cigancica”. Sphericity was similar in both cultivars. Fruit weight, soluble solids content, ripening index, and pH increased during ripening process, whereas titratable acidity decreased over above process. In general, “Oblacinska” had better chemical composition than “Cigancica”. Finally, fruit of both cultivars is suitable for processing and also for fresh consumption.

Strawberry (Fragaria X ananassa Duch.) yiel das affected by the soil pH

Two-year trials (20062007) suggested that the use of calcium oxide (CaO) on acid soils increased soil pH and yields in strawberry cultivars Marmolada, Selena and Senga Sengana, under the environmental conditions of Cacak (Western Serbia). The highest yield was obtained when CaO was applied at 750 kg ha-1 rate. Further increase in rate up to 1,500 kg ha-1 did not show corresponding increase in yield; the result was a slight yield drop compared to the peak yield shown at 750 kg ha(1) rate. Overall, yields at rates above 750 kg ha(1) were still higher than control and in the treatment employing lowest CaO application rate of 250 kg ha-1.

Apricot Vegetative Growth, Tree Mortality, Productivity, Fruit Quality and Leaf Nutrient Composition as Affected by Myrobalan Rootstock and Blackthorn Inter-Stem

The behavior of five apricots grafted across Blackthorn inter-stem (BI) on Myrobalan stock and on Myrobalan rootstock (MR) was evaluated through vegetative growth, tree mortality, productivity, fruit quality and leaf nutrient composition from the 1st to the 6th leaf. The trial was performed in the Prislonica village (Cacak, Serbia), on a dry, shallow, sandy-loam and acidic soil. Results showed that MR improved tree vigor, yield per tree, cumulative yield, fruit weight, flesh rate, acidity, antioxidant power, leaf N, K, Ca and Mn contents and better balanced nutritional values for macronutrients. BI increased tree mortality, yield efficiency, yield per hectare, total phenolic and total flavonoid contents, and leaf P and Fe amounts. Wide variability among cultivars for evaluated traits was observed on both BI and MR. The more vigorous trees had ‘Biljana’ as compared with others on both BI and MR, whereas the most productive cultivar was ‘Vera’ on BI and ‘Biljana’ on MR. The highest and similar fruit weight had ‘Roxana’ and ‘Harcot’, whereas the highest stone weight and flesh rate was found in ‘Vera’ and ‘Harcot’, respectively, all in both BI and MR. Fruits harvested from ‘Aleksandar’ trees were rich in soluble solids content (SSC), titratable acidity (TA) and total flavonoid content (TFC), ‘Harcot’ in total phenolic content (TPC), and ‘Roxana’ in acidity and total antioxidant capacity (TAC), also on both BI and MR. The better balanced nutritional values were promoted by BI. Regarding cultivars, the best balanced nutritional values for macronutrients were exhibited by ‘Vera’ on BI, and by ‘Harcot’ on MR. For micronutrients, the wider imbalance among nutrients was found in ‘Roxana’ on BI, and in ‘Vera’ on MR.ZusammenfassungDas Verhalten von fünf Aprikosensorten, die auf Prunus myrobalana mit Zwischenveredlung Schlehe (BI) und direkt auf Prunus myrobalana (MR) veredelt worden waren, hinsichtlich vegetativem Wachstum, Baumsterblichkeit, Ertragsleistung, Fruchtqualität und Ernährungszustand wurde vom ersten bis zum sechsten Laub überprüft. Der Versuch wurde in Prislonica (Cacak, Serbien) auf einem trockenen, flachgründigen, sandig-lehmigen und sauren Boden durchgeführt. Die Ergebnisse zeigten, dass die Verwendung der Unterlage Prunus myrobalana die Wuchsstärke des Baumes, den Baumertrag, den kumulativen Ertrag, das Fruchtgewicht, den Fruchtfleischanteil, die Säure, das antioxidative Potential und den Blattgehalt der Hauptnährstoffe N, K, Ca und Mn verbessert und zu einem besser ausgewogenen Verhältnis der Makronährstoffe beiträgt. BI erhöhte die Baumsterblichkeit, den spezifischen Ertrag, den Ertrag pro Hektar, die Gesamt-Phenol- und Flavonoid-Gehalte und den Blattgehalt bezüglich P und Fe. Zwischen den Sorten wurde bei den erfassten Merkmalen sowohl bei BI als auch bei MR eine große Schwankungsbreite festgestellt. Verglichen mit den anderen Sorten brachte ‘Biljana’ sowohl auf BI als auch auf MR die wüchsigsten Bäume hervor, wohingegen ‘Vera’ den höchsten Ertrag auf BI und ‘Biljana’ den höchsten Ertrag auf MR erbrachte.Unabhängig von der Unterlage zeigten sich folgende Ergebnisse: Das höchste Fruchtgewicht hatten, mit geringem Unterschied, die Sorten ‘Roxana’ und ‘Harcot’, während ‘Vera’ den größten Stein-Anteil und ‘Harcot’ den höchsten Fruchtfleischanteil aufwies Früchte, die von der Sorte ‘Aleksandar’ geerntet wurden, waren reich an löslicher Trockensubstanz (SSC), titrierbarer Säure (TA) und absolutem Flavonoid-Gehalt (TFC). Die Sorte ‘Harcot’ hatte einen hohen Gesamt-Phenol-Gehalt und ‘Roxana’ war reich an Säure und hatte ein hohes antioxidatives Potential.Von BI wurde im Allgemeinen ein besser ausgewogenes Nährstoffverhältnis gefördert. Wenn man die Sorten betrachtet, war das am besten ausgewogene Verhältnis der Makronährstoffe bei ‘Vera’ auf BI und bei ‘Harcot’ auf MR zu finden. Bei ‘Roxana’ auf BI und bei ‘Vera’ auf MR gab es die größten Schwankungen bei den Mikronährstoffen.

VEGETATIVE GROWTH, FRUIT WEIGHT, YIELD AND LEAF MINERAL CONTENT OF PLUM GROWN ON ACIDIC SOIL

The experiment was established at a spacing of 4 m × 2 m. Ten plum cultivars were grafted on the vegetative rootstocks ‘Belosljiva’ (Prunus domestica L.). Until the fifth and the sixth year after planting, the vegetative growth, fruit weight (FW), and yield properties were affected by the cultivar. The FW was the highest in ‘Cacanska Rana’ (‘CRa’). ‘Cacanska Najbolja’ (‘CNa’) had the highest one-year-old shoot length (SL). ‘Stanley’ (‘STa’) was the most productive cultivar in 2006 and ‘Cacanska Rodna’ (‘CRo’) in 2007. Yield efficiency (YE) was the highest for ‘CRo’. Significant differences were observed among cultivars for leaf macronutrient [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg)] and micronutrients [iron (Fe), manganese (Mn), zinc (Zn), boron (B)] levels at 120 days after fool bloom (DAFB). According to the ΣDOP index, ‘CRa’ and ‘STa’ showed the best balanced macronutrient and micronutrient values, respectively. The leaf Mn, Fe and N content was significantly correlated with SL, FW, and YE.

Influence of Mineral Fertilizer, Farmyard Manure, Natural Zeolite, and their Mixture on Fruit Quality and Leaf Micronutrient Levels of Apple Trees

ABSTRACT Adequate soil conditions and fertilization as a cultural practice are the basis of fruit crops production. This study was conducted in 2011 and 2012 to determine impact of soil application of complex nitrogen, phosphorus, and potassium (NPK) mineral fertilizer alone and its mixture with cattle manure (M) and natural zeolite (A) on yield, fruit physico-chemical traits and leaf micronutrient amounts at 120 days after full bloom (DAFB) in “Idared” and “Melrose apples grown on heavy and acidic soil under Serbian conditions. Results showed that NPK increased yield in “Idared” and both NPK+A and NPK+M in “Melrose.” Fertilizer applications were not influenced by fruit physico-chemical attributes, but differences between cultivars were significant. Fertilizers induced changes of leaf micronutrients amount, but effect was not consistent. In “Idared,” NPK+A and NPK+M mixtures improved amounts of the most micronutrients, whereas in “Melrose,” NPK and mixture NPK+A+M increased leaf micronutrients in more cases. According to deviation from optimum percentage (DOP and ΣDOP indexes), excessive leaf iron (Fe) and zinc (Zn) was found and deficiency of manganese (Mn), copper (Cu), and boron (B). “Melrose” exhibited much better balanced nutritional values for nutrients as compared to “Idared,” whereas NPK+M in “Idared” and NPK alone in “Melrose” promoted better balanced nutritional values. Since the impact of nutrients on the studied features is not consistent, more research will need to be conducted to investigate the long-term effect of NPK alone or in mixture with natural zeolite and manure fertilization on apples.

Do the Rootstocks Determine Tree Growth, Productivity and Fruit Quality of Pears, which Grow on Typical Heavy and Acidic Soil?

During first 5 years after planting, we investigated the impact of quinces MA and BA.29 rootstocks on tree growth, precocity, yield, fruit quality and leaf nutrients content 60 days after full bloom (DAFB) of ‘Starking Delicious’, ‘Abbé Fetel’, and ‘Conference’ pear cultivars which are grown in the Cacak region on heavy and acidic soil. Results showed that rootstocks significantly influenced a small number of features which were evaluated. MA promoted better values of fruit weight and fruit length, whereas BA.29 increased leaf width and leaf area. Impact of rootstocks on tree growth and yield attributes were not found. A stronger effect than that of rootstock on all characteristics which were evaluated had the cultivar per se (genotype). Among cultivars, ‘Conference’ showed the highest values of leaf dimensions, leaf area and ripening index (RI); ‘Abbé Fetel’ had the highest flower numbers per umbels, cumulative yield, yield efficiency, all fruit physical characteristics, soluble solids content, titratable acidity, total sugar content and vitamin C content, while ‘Starking Delicious’ had the highest tree vigor, yield per tree and unit area.ZusammenfassungWährend der ersten fünf Jahre nach der Pflanzung wurde der Einfluss der Quittenunterlagen MA und BA.29 auf das Baumwachstum, den Ertragsbeginn, den Ertrag, die Fruchtqualität und den Blattnährstoffgehalt, 60 Tage nach der Vollblüte, bei den Birnensorten ‚Starking Delicious‘, ‚Abbé Fetel‘ und ‚Conference‘, die auf den schweren und sauren Böden der Region um Cacak angebaut werden, untersucht. Die Ergebnisse zeigten, dass die Unterlagen nur wenige der untersuchten Eigenschaften signifikant beeinflussten. Die Unterlage MA beeinflusste das Fruchtgewicht und die Fruchtgröße positiv, während BA.29 die Blattbreite und die Blattoberfläche vergrößerte. Ein Einfluss der Unterlagen auf das Baumwachstum und Ertragsparameter wurde nicht gefunden. Der Sorteneinfluss war im Allgemeinen größer. Unter den Sorten zeigte ‚Conference‘ die größten Abmessungen in Bezug auf das Blatt, die größte Blattfläche und den höchsten Reifeindex (RI). ‚Abbé Fetel‘ hatte die meisten Blüten pro Blütenbüschel und die höchsten Werte beim Gesamtertrag, der Produktivität, aller physikalischen Fruchtmerkmale, der löslichen Trockensubstanz, der titrierbaren Säure, des Gesamt-Zuckergehaltes und des Vitamin C-Gehaltes, während ‚Starking Delicious‘die größte Baumvitalität und den höchsten Ertrag pro Baum und Flächeneinheit aufwies.

Plum (Prunus spp.) Breeding

Despite over 6000 plum cultivars from 19 to 40 species that have originated in Europe, Asia and America, used for fresh market, processing, canning, drying and deep freezing, there is a continuing need to develop new cultivars through different breeding tools as the requirements of industry and market change. Most plums grown commercially are either hexaploid, Prunus domestica L. (European or domestic) or diploid, P. salicina L. (Asian or Japanese). The main goal of breeders of European plums are cold hardiness, modest tree size, self-fertility, regular productivity, excellent fruit internal and external quality, storage ability, resistance to Plum pox virus (PPV) and, recently, tolerance to climatic change and poor soils. Problems that compromise the production of Japanese plums are susceptibility to spring frosts, insufficient winter hardiness and limited soil adaptations. Basically, selection criteria are compatible in both Japanese and European plum breeding. Hybridization is still very popular in plum breeding programs. However, plum breeding using hybridization techniques is a very slow and expensive, so breeding work was stopped or been suspended for some time in many countries over the last few decades. Recently, research began on biotechnology with the aim of speeding up the breeding process by applying biotechnological methods and cytoembryological analysis. New cultivars in the near future will be developed using both conventional and genetic transformation techniques, especially in the private sector. This review is a synopsis of new European and Japanese cultivars and interspecific Prunus hybrids recently released around the world. Also, new breeding technologies are discussed.

Dynamics of pollen tube growth and embryo sac development in Pozna Plava plum cultivar related to fruit set

A newly released, late ripening plum cultivar Pozna Plava sets fruit poorly, although it produces high quality fruit. This study aimed to evaluate which factors in the reproductive process could be related to the lack of fruit set. In two consecutive years, establishment of a suitable polleniser and the stage of ovule development at anthesis as well as initial and final fruit set have been studied. In addition to this, the impact made by temperature fluctuations on the interaction between male gametophytes and female sporophytes was also analysed. Growth of the pollen tubes in the style and penetration into the nucellus as well as fruit set were more effective in cross-pollination than in open and self-pollination. A relative delay in ovule development was observed, and most ovules had an embryo sac with eight nuclei. Considering the results of the quantitiative parameter study of pollen tube growth in the ovary as well as the results of the stage of ovule development, a conclusion can be made that this cultivar is characterised by an extremely short effective period of pollination.