Mile Sečanski

Essential oils are complex mixtures of aromatic compounds produced through secondary metabolism in plants. They contain various substances such as hydrocarbons, alcohols, ketones, aldehydes, organic acids, and phenols. These oils have been used in medicine since ancient civilisations, including Egypt and China, as recorded in historical documents. Apart from their biological and ecological functions, essential oils also display antimicrobial, antiviral, and insecticidal properties. This paper focuses on the antiviral effects of essential oils. Plant viruses pose a significant threat to agricultural crops, as no effective treatments are currently available, leading to considerable economic losses. Numerous in vitro studies have shown that essential oils and their compounds from various medicinal and aromatic plants can act as powerful antiviral and virucidal agents. They work by inhibiting viral replication at different stages of the infection cycle in DNA and RNA viruses across different host cells. Essential oils are gaining attention as potential novel drugs with antimicrobial and antiviral properties. In plant protection, essential oils are recognised for their antiviral, antimycotic, and antiparasitic effects, and are considered promising for developing safe antimicrobial agents.

This study analyzes the impact of different nitrogen fertilization levels, in the form of UREA, on the growth and yield of spinach (Spinacia oleracea L.) under greenhouse conditions in Raška during the 2022 and 2023 growing seasons. The experiment was set up using a Randomized Complete Block Design with three replications, on a 12 m² plot. UREA (46% N) was applied in various rates (0, 40, 80, 120, and 140 kg ha⁻¹) to evaluate its effect on spinach growth and productivity. Key parameters such as plant height, days taken to first cutting, number of leaves per plant, leaf length, fresh weight of leaves, and yield per pot and hectare were measured. The results showed significant differences in most of the analyzed parameters. As the N rate increased, plant height, number of leaves per plant, leaf length, and yield increased, with the highest values recorded at 140 kg ha⁻¹. However, excessive doses showed diminishing returns, particularly between 120 kg ha⁻¹ and 140 kg ha⁻¹. The control group exhibited the lowest values for all parameters. Additionally, earlier flowering and potentially reduced quality with higher nitrogen doses were observed. The study concludes that optimal nitrogen levels are crucial for spinach yield and quality, and a balanced approach to fertilization is necessary to achieve sustainable production while minimizing environmental risks.

Seed germination is a complex biological process influenced by a combination of internal and external factors. This paper analyzes the impact of key environmental factors: temperature, water availability, light, pH value, and storage conditions on seed germination, with a particular focus on field crops. Temperature plays a crucial role in enzymatic activity and metabolic processes, with both excessively high and low temperatures negatively affecting germination due to oxidative stress and enzyme inhibition. Water availability is essential for seed rehydration and metabolic activation, while excess moisture can lead to anaerobic conditions that hinder germination. Light influences germination through photoreceptors that regulate hormonal balance, affecting dormancy and growth initiation. Soil pH affects nutrient availability and enzyme activity, with extreme pH levels inhibiting seed metabolism. Finally, storage conditions determine seed viability over time, with high humidity and temperature, accelerating biochemical degradation. Understanding these factors is crucial for optimizing seed germination and improving agricultural productivity, particularly in the context of climate change.

Maize is one of the economically most important crops. Its immense significance arises from its various uses, high yielding and the production scope. In order to establish a lucrative production, first-rate seeds are required. Therefore, the aim of this study was to test the vigour of maize seeds conventionally and organically produced. The seeds of the maize variety Rumenka were used and tested at the Maize Research Institute ?Zemun Polje? in its Seed Testing Laboratory. According to the results, it can be concluded that although there was a minimal difference in the percentages of the first count of germinated seeds between the two types of seeds, the total germination was equal (98%). The results of the germination test performed after accelerated seed ageing indicate that total seed germination was higher in organic than in conventional seeds (39% vs. 33%). The electrical conductivity of the leachate per gram of weight of conventional maize seeds averaged 4.90 ?S/cmg and 3.66 ?S/cmg for organic maize seeds. According to stated values, it can be concluded that maize seeds of both production types are characterised by high viability and are suitable for earlier sowing under unfavourable environmental conditions. The results show that the radicle emergence was uniform amounting to 84% in conventional seeds and to 85% in organic seeds.

Regardless of the plant species, organic cultivation is carried out according to legally prescribed principles, i.e. according to IFOAM standards. The products produced in this way are of high quality, without residues of pesticides and other chemicals. Soya is a plant of great economic importance, one of the most important field crops. It is used to produce important products for human and domestic animal nutrition as well as for industrial processing. The paper uses data from the Ministry of Agriculture, Forestry and Water Management of the Republic of Serbia for an analysis of the state of organic soya production in the Republic of Serbia. Soybean production based on organic principles has been successfully practised for many years, and the area under cultivation has increased fivefold in the last ten years. The largest production of organic soybeans takes place in Vojvodina (477.04 ha), where the agro-ecological conditions are the most favorable. However, on the entire territory of the Republic of Serbia, organic soybean production is still small, considering the exceptional ecological conditions and market needs.

Maize husk mass affects the dynamics of maize kernel moisture release as well as the yield and harvest timing of maize. The aim of this study was to observe the dynamics of moisture release in maize husks depending on the sowing density technology used. At the Zemun Polje location, a trail was established with three hybrids (H1-ZP 4708, H2-ZP4242, H3-ZP4790) in three densities (G1-40,816, G2-69,689, G3-89,286). During the vegetation period, 15 days after fertilization, four samples (V1-V4) were taken to determine the fresh and dry weight of the husk. The leaves were dried in an oven at 60°C for 12 hours. The effect of the genotype was reflected in the different mass of the maize husks and the dynamics of moisture loss. It was most pronounced in hybrid ZP 4242, which had the highest moisture loss between V1 and V4 samples at 9.86 %. It is also the hybrid with the highest fresh mass of leaves, 88.71 g. The dynamics of mass reduction, i.e. moisture loss, was linear in all hybrids, except for the exceptions by ZP 4242. The effects of sowing density and genotype on the moisture release of the maize husks and thus the maize kernel lead to an optimal harvest and a reduction in the risk of yield loss.

Biological control refers to the use of living beneficial organisms as well as the products of their metabolism in pest control. Weed plants are indispensable companions of cultivated plants, in which they cause substantial damage. Organic food production, human health care and environmental preservation impose a need for the production and application of bioherbicides, particularly in organic systems of plant production. Plant pathogens have significant potential as biological agents in weed control. The aim of the present study was to indicate the most important properties of the weed biological control system, with particular emphasis on the use of fungi-based bioherbicides. According to the organism they suppress, biopesticides are classified into bioinsecticides, biofungicides, bioherbicides, etc. Weed control using plant pathogens can be performed in three ways, by classical, conservation and augmentative biological control. Bioherbicides were initially introduced to the market in 1980, and the majority of them were fungi-based bioherbicides. The most common fungi included in bioherbicides belong to the genera Alternaria, Colletotrichum, Cercospora, Fusarium, Phomopsis, Phytophthora, Phoma, Puccinia, etc. The studies, development and final commercialisation of fungi as biological control agents face many obstacles, ranging from basic biological facts to social and economic factors. There are also challenges in the production, formulation process, environmental friendliness, duration of herbicidal action, and expensive and time-consuming registration procedures. Considering the success in weed suppression with fungi-based bioherbicides, the global market is still dominated by chemical companies manufacturing synthetic herbicides, while there are no such products on the Serbian market yet.

The aim of this study was to assess the chemical composition and bioactive properties of the wholegrain flour obtained from eleven maize inbred lines to identify genotypes with increased potential for the development of hybrids with high nutritional and functional value, suitable for food production. The maize inbreds, including seven standard yellow, two QPM (quality protein maize) and two lines for red kernel hybrids, were grown in the experimental field of the Maize Research Institute at the location of Zemun Polje, Serbia. Wholegrain maize flour was got by grinding the maize grain in a laboratory mill. The assessment of the chemical composition and content of certain bioactive compounds, as well as the total antioxidant capacity, was conducted using standard laboratory procedures. The highest starch content (73.73%) was determined in line L8, while line L10 had the highest protein content (12.82%). Among soluble proteins, the a-zein fraction was dominant in most of the lines, ranging from 0.92% to 3.57%. The highest content of total fibres (NDF) was determined in red kernel line L9 (15.77%). Line L8 was the richest in total carotenoids (21.08 mg bCE/g d.m.), while line L7 had the highest total antioxidant capacity (34.30 mmol Trolox/kg d.m.), which can be explained by the presence of anthocyanins in the red grain. Line L1 had the highest content of total sugars (3.36%), and line L4 had the lowest (1.44%). Most of the samples of inbred lines investigated in this study showed good quality parameters regarding chemical composition and bioactive properties. The obtained results may provide some valuable guidelines needed in the following stages of maize breeding and open up various possibilities for the utilization of wholegrain maize flour in the food industry.

Summary: The quality and provenance of seed are of exceptional importance for the production and yield of cultivated plants. There are numerous tests for determination of seed vigour. The seed accelerated ageing test is one of the most important tests that provide determination of the degree of germination preservation and the seed longevity in storages. The aim of this study was to observe the effect of different production methods – organic and conventional – on seed vigour of maize (variety Rumenka), using the seed accelerated ageing test. Maize seeds were exposed to double stress conditions (temperature of 45 °C, air humidity of 100%) for 72h. Maize seed germination was determined by the standard germination test and was expressed as a percentage. The results of vigour of maize seeds organically produced indicated that the application of the seed accelerated ageing test increased the first count (78.5%) in relation to the standard germination test (70.75%), and a significantly higher percentage of nongerminated seeds (10.25%) were recorded. Furthermore, the radicle length decreased (120.75 mm), while the length of the seedling above-ground part (117.13 mm) and fresh weight (4.56 g) increased. In maize seeds conventionally produced, the first count and germination were higher (41.5% and 46.25%, respectively) after the application of the seed accelerated ageing test, while the percentage of nongerminated seeds were higher (38.75%). In addition, the length (105.88 mm) and fresh weight (4.43 g) of the seedling above-ground part decreased, while the values of the radicle length (137.5 mm), fresh weight (2.39 mm) and dry weight (0.28 mm) as well as dry weight of above-ground parts of seedlings (0.31 g) were higher than after the application of the standard laboratory method (127.88 mm, 1.89 g, 0.17 mm and 0.31 g, respectively).

Summary: Over the past few years, both producers and consumers have become increasingly interested in organic farming because conventional agriculture relies so heavily on the use of synthetic pesticides, thus causing environmental pollution. Weeds, as inevitable "companions" of cultivated plants, represent a major, everlasting issue in plant production. As organic plant production is legally regulated, the control of undesirable plants such as weeds is further complicated. Using the relevant literature, the purpose of this study is to survey the existing weed control methods in organic crop production. In order to be certified, organic plants have to be grown in the farming system without the application of synthetic herbicides and other chemicals that are commonly used in conventional production. This means that crop growers have to apply non-chemical, alternative methods of weed suppression, i.e. weed control based on the combination of cropping practices, mechanical control, and the use of bioherbicides. There is a large number of plant extracts with bioherbicidal activity, the effect of which is mostly attributed to the biological phenomenon of allelopathy, rendering such weed control sustainable, inexpensive, and environmentally friendly. Although bioherbicides are successfully used in organic farming worldwide, there are no registered bioherbicides in Serbia to date (according to the data of the Ministry of Agriculture, Forestry and Water Management of the Republic of Serbia). Both organic producers and experts should raise awareness of the importance of successful weed control to the health of cultivated plants, soil, beneficial organisms, and the entire ecosystem, which requires further research attention.