Darko Jovanović

The aim of this study was to evaluate the effects of irrigation level, soil type, and microbial biostimulants on fruit weight and fruit number per plant of the pepper genotype "Moravska lepotica". The experiment was conducted during 2025 in the greenhouse of the Institute for Vegetables Crops Smederevska Palanka, on land originating from three locations important for the production of peppers in Serbia (Ruski Krstur, Donja Lokošnica and Smederevska Palanka). The experiment included a control treatment and three treatments with biostimulators (Azoter F - Trichoderma atroviride, Biofor active and Folisu) in three repetitions with 10 plants per treatment. Statistical analysis (ANOVA) showed a significant effect of factors and the interaction of irrigation × locality × treatment on fruit weight per plant. The highest fruit weight per plant (110.95 g) was measured at the full irrigation norm on the land from Donja Lokošnica in the Biofor active treatment. In contrast, at the reduced norm, the highest value (86.45 g) was recorded on land from Smederevska Palanka. The lowest average weight (32.22 g) was measured on the soil from Ruski Krstur in the Azoter F treatment at 50% of the irrigation norm. At the reduced irrigation norm, the highest number of fruits was obtained on Ruski Krstur with Azoter F (8.7) and Folis (7.8), while the control yielded the fewest (4.5).

The research aimed to evaluate the impact of a combination of pelleted manure (PS), zeolite, and calcium on the quality parameters of pepper fruit, particularly total soluble solids (TSS) and dry matter. The trial included a control treatment and three variants with the application of the mentioned fertilisers. The highest average TSS content (8.60 °Bx) was observed in the PS + zeolite + Ca combination, which showed a significant increase compared to the control (8.20 °Bx). The highest dry matter content (9.39%) was also recorded in the same treatment, while the application of only calcium led to an increase of about 0.55% compared to the control. A strong positive linear correlation was found between TSS content and dry matter, indicating that a reduction in water content in the fruit directly increases the concentration of total soluble substances. The combination of pelleted manure, zeolite, and calcium was the most effective in improving the nutritional quality of pepper fruits.

The research was performed in 2024 at two sites in Serbia, at the Institute for Vegetable Crops Smederevska Palanka and a family farm in Donja Lokošnica near Leskovac. The paper researched the differences in crude fiber content between two pepper genotypes: ‘Moravska lepotica’ and ‘Lokošnička’. The crude fiber content was determined by the Scharrer-Kürschner method. Data were analyzed by using IBM SPSS Statistics, version 26.0. A higher crude fiber content was recorded in the fruit of the genotype ‘Lokošnička’ (locality Smederevska Palanka 3.75% and Donja Lokošnica 2.89%) compared to the genotype ‘Moravska Lepotica’ (locality Smederevska Palanka 3.25% and Donja Lokošnica 0.53%). The values at the Donja Lokošnica locality are on average 51.3% lower than at the Smederevska Palanka locality. The high uniformity of the results within the groups, shown by the minimal interquartile range, additionally confirms the stability of the obtained differences.

The challenges of food security and climate change require the development of sustainable methods in agriculture, such as biological seed treatment. This research examines the effect of inoculation of squash seeds (Cucurbita pepo L., genotype Fina) with a mixture of strains of Bacillus sp. on the morphological characteristics of seedlings. The experiment was conducted in the greenhouse of the Institute for Vegetable Crops Smederevska Palanka during April-May 2024. The seeds were inoculated before sowing, a control (seeds treated with distilled water) was also included. The properties of plant height, steam diameter, width and length of the first true leaf, mass of the above-ground part of the plant and root mass were analyzed. The results show a statistically highly significant effect of the treatment on plant height (17.3 cm in the treatment versus 12.8 cm in the control), while no statistical significance was established for the other traits, but higher values were measured in seedlings of inoculated seeds. Positive correlations were found between the plant height and the mass of the above-ground part of the plant (r=0.684**), as well as between the mass of the above-ground part of the plant and the width of the first true leaf (r=0.546*). These results indicate the potential of biological treatment to improve the growth of squash seedlings, which is a significant contribution to sustainable production with reduced use of chemical agents.

The aim of this research was to investigate and characterise the anatomical structure of vegetative organs in Echinochloa crus-galli (L.) Beauv., commonly known as cockspur or barnyardgrass. E. crus-galli is a member of the Poaceae family and a common weed species which occures in many crops. For the purposes of this research, fully developed plants were collected from the experimental field of the Institute of Vegetable crops in Smederevska Palanka. Several methodes of microslide preparation were employed to investigate the anatomy of root, stem, and leaf. Cockspur has high water requirements and belongs to the hygrophilous weed species (F4), which is anatomically reflected by the presence of large intercellular spaces (aerenchyma) present in the stem and root. Generally speaking, the anatomical characteristics of E. crus-galli, especially considering not only lignified endodermis, but also presence of lignified exodermis in roots, share similarities with anatomical characteristics of rice (Oryza sativa L.), in whose fields this species is considered one of the most troublesome weeds. The anatomical structure of the stem is typical of monocots, featuring a single-layered epidermis on the surface, a hypodermis composed of chlorenchyma and sclerenchyma, and collateral vascular bundles. The collateral vascular bundles were distributed in a pattern characteristic of the Poaceae family, and scattered throughout the stem's main body, surrounded by well-developed parenchyma tissue. The leaves are characterized by Kranz anatomy, which is typical of plants with C4-type photosynthesis. The leaf surface is characterized by the presence of short, non-glandular trichomes on both the adaxial and abaxial leaf surfaces, while silica cells are located exclusively in the adaxial epidermis. These morpho-anatomical characteristics could be an significant factor in the absorption of foliar-applied herbicides, making their understanding crucial for effective chemical control.

Limited soil fertility and unfavorable climatic conditions significantly affect vegetable production, which requires the application of innovative fertilization strategies. In this research, the influence of organic fertilizer based on plant extracts containing phenolic compounds and phytohormones on the productive and morphological characteristics of melon (Cucumis melo) grown on acidic and poorly supplied soil (pH 3.74, humus 2.4%) was investigated. The experiment was set up in 2024 on the experimental field of the Institute of Vegetables in Smederevska Palanka according to a random block system in three repetitions. The treatments included one (Tr1), two (Tr2) and three (Tr3) fertilizer applications, as well as a control without fertilization. The results showed no statistically significant differences in fruit weight between treatments (1.03-1.23 kg). However, the number of fruits per plant was significantly higher in Tr3 (24), while Tr1 had the highest number of lateral branches (23.80). The largest peel thickness was determined in Tr2 (0.51 cm), which may contribute to better post-harvest durability of the fruits. The highest chlorophyll content was measured in the control variety (65.43 SPAD units), while there were no significant differences in sugar content between treatments (11.31-11.97 ºBrix). Correlation analysis showed a positive highly significant relationship between fruit mass and sugar content (r = 0.41**), while the number of fruits and the number of side branches were negatively related (r = -0.31**). The results indicate that organic fertilizer based on plant extracts can improve certain productive properties of melon in nutrient-poor soil conditions. Further research is needed to optimize the application strategy in different agroecological conditions.

The experiment was set up during 2016 and 2017 in the Leskovac area on an alluvial soil. For research purposes, the duration of certain phenological phases, the entire vegetation period of 6 maize hybrids, and three FAO maturity groups (400-600) were monitored. The research aims to determine the duration of each phenological phase and the entire growing season based on the number of days, the sum of the total, and the sum of the effective temperatures, and to recommend suitable hybrids for the investigated area. In terms of years and sowing dates, the difference in vegetation period between the hybrid with the longest and the hybrid with the shortest vegetation period was 38 days, the difference in SUT was 414.7?C, and the difference in SET was 240.0?C. On average over two years, the lowest sum of effective temperatures was measured at 1158.8?C for the FAO hybrid group 400, ZP 434, and the highest at 1398.9?C for the FAO hybrid group 600, NS 6030. Depending on the temperature conditions, the year in the first sowing period of the individual phases was shortened with increasing temperature. The onset of periods with lower air temperatures and the length of the phenological phases lasted longer. The method of the sum of effective temperatures proved to be the most reliable method for determining the vegetation length of the maize hybrids examined.

The field experiment was conducted during 2021 and 2022 at the Maize Research Institute Zemun Polje, Zemun Polje in Serbia. The goal of this study was to evaluate the influence of adjuvants and nozzle types on the efficacy of two herbicides based on the same active ingredient - nicosulfuron. The study was arranged as a split-block design in four replication with 12 treatments plus weed-free, as well as weedy season long treatments. Weeds were sampled 21 day after treatment (DAT) and both fresh and dry biomas were measured (only dry biomass is shown). Visual estimation of efficacy was assessed 7, 14 and 21 DAT. Among all treatments no differences between herbicides were observed. In addition, treatments with AMS showed a lower level of efficacy compared to treatments with non-ionic surfactant (NIS) adjuvant where the efficacy was higher and where it led to faster weed decay. Based on dry biomass reduction, all factors had a statistically very significant impact on the results, both individually and in mutual interaction.