Botryosphaeriaceae species causing stem blight and dieback of blueberries in Serbia

In the main growing areas in Serbia, plants with symptoms of stem blight were sampled in nine orchards with American highbush blueberry (Vaccinium corymbosum), cultivar ‘Duke’, with high disease incidence, and 153 samples were taken. A total of 128 Botryosphaeriaceae isolates were characterized on the basis of morphology, sequence analysis, multilocus phylogeny based on ITS, TEF1-α and TUB2 sequences and pathogenicity, and belonged to one of the four species Neofusicoccum parvum, Botryosphaeria dothidea, Diplodia seriata and Lasiodiplodia iraniensis. Both D. seriata and L. iraniensis were detected for the first time on blueberries in Serbia, and L. iraniensis was detected for the first time on blueberries worldwide. Comparative morphological and TEF1-α sequence analyses allowed a clear separation of L. iraniensis from the phylogenetically closely related L. fujianensis, L. thailandica and L. endophytica. Of the nine blueberry cultivars ‘Aurora’, ‘Barbara Ann’, ‘Bluecrop’, ‘Bluejay’, ‘Draper’, ‘Duke’, ‘Huron’, ‘Patriot’ and ‘Spartan’ inoculated with L. iraniensis (isolate 421-19), the cultivar ‘Duke’ was the most susceptible. In our study, the majority of orchards were in their second or third year of production, implying that the planting material is likely to be the source of infection, emphasizing the importance of pathogen-free planting material

Pollen–pistil interactions in autochthonous Balkan sweet cherry cultivars – the impact of genotype and flowering temperature

The efficacy of sweet cherry production is highly dependent on the regularity of flowering events and genetic-determined relations between female sporophyte and male gametophyte, which became even more important with higher flowering temperatures caused by climate change. Special attention is paid to the genetic diversity that provides essential sources of potential temperature-tolerance genes. Our study aimed at the genetic and reproductive characterization of Balkan cherry cultivars of autochthonous origin (‘Canetova’, ‘G-2’, ‘Dolga Šiška’ and ‘Ohridska Crna’), and six potential pollinizers. To identify S-haplotypes, the polymerase chain reaction (PCR) method was used to detect the S-ribonuclease (S-RNase) and S-haplotype-specific F-box protein (SFB) alleles, combined with fragment analysis and S-RNase sequencing. Pollination experiments were performed at three Balkan localities over two flowering seasons, and the fluorescence microscopy method was used to assess the cultivars’ male/female reproductive behaviour. A novel S-RNase allele S40 was identified in ‘Ohridska Crna’ for the first time. ‘Ohridska Crna’ also demonstrated the best adaptability to higher temperatures regarding primary ovule longevity. This feature makes it desirable from the aspect of breeding new cultivars that can withstand the impacts of climate change. The findings on male-female relations and their temperature dependence open up the possibility for yield prediction and smart horticultural decisions that can be made to guide cherry production

Raspberry leaf blotch emaravirus – značajna pretnja proizvodnji maline u Srbiji

Raspberry leaf blotch emaravirus (RLBV) is a recently characterized virus infecting raspberries. RLBV has been reported in numerous European countries, and it is vectored by the raspberry leaf and bud mite (Phyllocoptes gracillis). Virus infection is manifested by light green and yellow leaf blotches and patches, leaf twisting, and distortion of leaf margins. RLBV is the most important virus infecting raspberries in Serbia, causing severe leaf symptoms, including cultivar ‘Willamette’ that is dominant in the orchards, with a share of about 90%. Results of the conducted research in the last decade confirmed wide distribution and significant genetic diversity of RLBV in Serbia. It was detected in all raspberry-growing regions in all tested cultivars. The fruit of the raspberry ‘Willamette’ proved to be significantly affected by RLBV infection. Depending on the locality and altitude, the recorded reduction of fruit weight was up to 27%. On the other side, soluble solids content in infected fruits was higher. The results of the study on the changes in chemical composition of ‘Willamette’ fruits confirmed the influence of RLBV infection on the examined phenolic profile, but this influence was quite minor compared to the influence of soil composition and weather conditions.Virus mrljavosti lista maine (raspberry leaf blotch emaravirus, RLBV) je nedavno okarakterisan virus koji zaražava maline. RLBV je prisutan u brojnim evropskim zemljama, a prenosi ga eriofidna grinja lista maline (Phillocoptes gracillis). Simptomi zaraze su svetlozelene i žute mrlje i pege na listovima, uvijanje listova i deformacije ivica lišća. RLBV je najvažniji virus koji zaražava malinu u Srbiji, izaziva jake simptome na lišću različitih sorti, među kojima je i sorta Vilamet koja je dominantno prisutna u zasadima sa učešćem od oko 90%. Rezultati istraživanja koja su sprovedena u poslednjoj deceniji potvrdili su široku rasprostranjenost i značajan genetski diverzitet RLBV u Srbiji. Prisustvo RLBV je potvrđeno u svim regionima gajenja maline kod svih ispitivanih sorti. Utvrđeno je da RLBV značajno negativno utiče na plodove sorte Vilamet. U zavisnosti od lokaliteta i nadmorske visine zabeleženo je smanjenje mase ploda do 27%. Sa druge strane, sadržaj rastvorljivih suvih materija u zaraženim plodovima bio je veći. Rezultati sprovedenih istraživanja promena hemijskog sastava plodova maline Vilamet pokazali su i uticaj RLBV infekcije na ispitivani fenolni profil, ali je ovaj uticaj bio neznatan u poređenju sa uticajem samog zemljišta i vremenskih uslova

Quality monitoring of apple fruit during long-term cold storage

This study aims to evaluate the post-harvest characteristics of two commercial apple cultivars (ʻGloster’ and ‘Morren’s Jonagored®’), examining their quality at harvest and after storage for different period (0, 2, 4, 6, and 8 months). Physical (fruit weight, weight loss, and firmness) and chemical traits (total sugars content (TSC), titrable acidity (TA), and TSC/TA ratio) were determined using standard laboratory methods. A comparison of the apple cultivars showed that ‘Morren’s Jonagored®’ had a higher fruit weight (217.87 g), while ‘Gloster’ exhibited higher fruit firmness (10.18 kg cm-2). The TA content was higher in ‘Gloster’ (0.45%), while TSC/TA ratio was higher in ‘Morren’s Jonagored®’ (32.96). No significant differences were observed in weight loss and TS content. At harvest, fruits of the apple cultivars exhibited the highest values for weight and firmness. During cold storage, a decrease was observed, and after 8 months, the investigated quality parameters showed the lowest values, along with the highest fruit weight loss (10.10%). The highest TSC content in apple fruit was recorded after 2 months of storage (10.33%), TA after 4 months (0.43%), while the highest TSC/TA ratio was observed at the end of the cold storage (35.03). A throughout analysis indicates that both cultivars are well-suited for long-term cold storage, as no significant changes were observed in the physical and chemical properties of the apple fruits throughout the storage period. This stability suggests their potential for extended shelf life and consumer acceptance

Fruit Weight and Primary Metabolites Content of Plum Fruits as Affected by Planting Density

An experiment was conducted to evaluate the effect of different dense planting (4×1 m; 4×2 m and 5×3 m) on the fruit weight and contents of primary metabolites (soluble solids, total sugars, invert sugars, total acids, and pH) in the fruits of eight plum cultivars (‘Čačanska Rana’, ʻČačanska Lepotica’, ‘Timočanka’, ‘Krina’, ‘Mildora’, ʻČačanska Najbolja’, ʻČačanska Rodna’ and ‘Stanley’). During the three-year experimental period, results showed variability in fruit weight and chemical composition between different cultivars and planting densities. The highest fruit weight was recorded at the planting distance of 4×2 m in cultivars ʻČačanska Rana’, ʻČačanska Lepotica’, ʻKrina’, ʻMildora’ and ʻČačanska Najbolja’, while the cultivars ʻTimočanka’, ʻČačanska Rodna’ and Stanley’ had the highest value at the standard distance of 5×3 m. Regarding primary metabolites, in all tested cultivars, the accumulation and synthesis of soluble solids and sugars in the fruit increased with increasing planting density, while pH and total acids showed the opposite trend. The present results indicated that different planting densities have an important effect on fruit weight and plant metabolism, promoting the synthesis and accumulation of primary metabolites in the fruits, thus positively affecting the quality and commercial value of the fruit

Enhancing productivity and quality of blackberries ‘Čačanska Bestrna’ with bioregulator Regalis application

Background: Blackberry (Rubus subg. Rubus Watson) is valued for its nutritional content, and optimizing its production is crucial in temperate regions like Serbia. Plant growth regulators (PGRs), such as Regalis (Prohexadione-Ca), have potential to enhance yield and fruit quality by modulating plant growth. This study evaluates the effects of Regalis on the ‘Čačanska Bestrna’ blackberry cultivar in Serbia. Objective: This study aims to assess the impact of Regalis on vegetative growth, yield, fruit quality, and nutrient composition of blackberries. Methods: The study was conducted at two locations in Western Serbia on blackberry canes foliar treated with the growth regulator Regalis and compared to untreated control bushes. Physical and chemical fruit traits were determined by validated analytical procedures. Mineral content was analyzed by atomic absorption spectrophotometry. Results: The results showed that Regalis significantly improved yield, fruit size, soluble solids, sugars, and micronutrient content, with effects varying by cultivation site. Conclusions: Regalis is an effective tool for enhancing blackberry yield and quality, especially under specific agro-ecological conditions in Serbia. Further research on long-term effects is recommended

Postharvest quality of Granny Smith apples: Interplay of harvest stage, storage duration, and shelf-life

Apples are the most widely consumed temperate fruit worldwide and are often stored for long-term to ensure year-round availability. However, maintaining fruit quality during storage and subsequent shelf-life remain a significant postharvest challenge. This study investigated the combined effects of the harvest stage, cold storage duration, and shelf-life on the physico-chemical properties of Granny Smith apples. Key quality attributes including texture, maturity indices, color, and starch degradation were evaluated using instrumental methods and Raman microscopy. Fruit quality was affected differently by individual factors and their interactions. Texture parameters showed varied sensitivity: the harvest stage affected several parameters, storage duration had the strongest overall impact, shelf-life influenced a moderate number of parameters, and some were affected by combined factor interactions. Maturity indices were significantly influenced by all factors individually and combined. Color parameters were consistently affected by harvest stage and storage, with shelf-life and interactions influencing fewer parameters. These findings emphasize the complex interplay of factors shaping apple quality after harvest. The study demonstrates the importance of timing harvest and tailoring postharvest handling to maintain apple quality. It also demonstrates the potential of combining traditional and advanced techniques for effective ripeness monitoring

Characterization of self-incompatibility genotypes in 48 sweet cherry cultivars and 21 promising hybrids bred in the Balkan region

Sweet cherry (Prunus avium L.) exhibits gametophytic self-incompatibility, controlled by at least two multi-allelic, linked genes located at the S-locus. During bloom, pollination with compatible genotypes is essential to ensure sufficient commercial fruit production. Although numerous cultivars and landraces have been S-genotyped, limited data are available on sweet cherry material developed through breeding efforts in the Balkan countries. Therefore, this study was undertaken primarily to identify S-genotypes of 69 sweet cherries, comprising 44 released cultivars, 17 candidate cultivars or promising hybrids, and eight parental genotypes developed or utilized in breeding programmes across Serbia, Romania and Bulgaria. We used PCR method for detection of S-alleles, combined with DNA fragment analysis and S-RNase sequencing to evaluate sweet cherry genotypes. We identified a novel S-RNase allele, named S39, in the Romanian sweet cherry cultivar ‘Amar Maxut’ and 10 different known S-RNase alleles (S1–S6, S9, S12, S13 and S22), which allowed classification of 69 genotypes into 21 known incompatibility groups (IGs), a ‘0’ group of universal pollen donors, and an ‘SC’ group of self-compatible genotypes. The pedigrees of released cultivars and promising hybrids were discussed based on the polymorphism of the S-locus. This study expands our knowledge of new universal pollen donors, self-compatible genotypes and S-locus combinations, while resolving uncertainties in previous S-genotyping and providing valuable insights for breeders and growers

How do plums ripen in two weather different years? A deep insight into the metabolomic profile

The aim of this study was to analyse the ripening process of two European plum cultivars, ‘Nada’ and ‘Stanley’. As the effects of climate change are becoming increasingly evident, plum producers are facing new challenges. Therefore, the study was conducted in two consecutive years (2021 and 2022) characterised by different weather conditions during the ripening of the plum fruit. The first harvest was performed when 70 % of the fruit surface was covered with cultivar characteristic colour, while the last sampling date coincided with fruit drop. In addition to the basic fruit quality parameters (fruit weight, firmness, total soluble solids), 35 primary and secondary metabolites (sugars, organic acids and phenolics) were identified and quantified by HPLC analysis. Certain trends such as the decrease in fruit firmness, the accumulation of sucrose and anthocyanins and the degradation of malate, were observed during the ripening of two cultivars studied. No clear trend was observed for hydroxycinnamic acids, flavonols, flavanols and flavanones, although the most dominant phenolic compound in all ripening stages was 3-caffeoylquinic acid. Principal component analysis showed that ripening was largely cultivar-dependent and that the behaviour of the same cultivar differed between growing seasons. It was found that heat waves in combination with drought periods accelerated the ripening process, which had a particular effect on the softening rate.This is the peer-reviewed and accepted version of the manuscript: Korićanac, A., Milatović, D., Popović, B., Tomić, J., Mitrović, O., Glišić, I., Pešaković, M., Rusjan, D., Veberic, R., Smrke, T., Grohar, M.C., Jakopic, J., 2025. How do plums ripen in two weather different years? A deep insight into the metabolomic profile. Postharvest Biology and Technology, 222, 113362. https://doi.org/10.1016/j.postharvbio.2024.113362 This work is licensed under CC BY-NC-ND license

Molecular detection and characterization of cherry virus A in sweet cherry, apricot and plum in Serbia

Cherry virus A (CVA) is a graft transmissible virus that infects cherries and other stone fruit species. One hundred six trees of sour and sweet cherry, plum, apricot, and peach from 22 locations in Serbia were tested for the presence of CVA. RT-PCR analysis of 106 samples revealed the CVA presence in 13 samples, including eight sweet cherries, three apricots, and two plums. Sequence analysis of the partial movement protein gene confirmed that Serbian isolates share 89.07–100% nucleotide identities with CVA sequences in GenBank. Our CVA isolates from apricots and plums share 100% nucleotide sequence identity with isolates from Australia, Hungary, Russia, and the Czech Republic. Isolates from sweet cherries showed 100% identity with isolates from Canada, China, India, and the Czech Republic. Phylogenetic analyses based on the ML method showed that the Serbian CVA isolates belonged to three out of six identified groups. No clear grouping of isolates based on geographical origin was evidenced, but there is a strong association between groups and host plants. Our results reveal the presence of CVA for the first time in apricots and plums in Serbia