Competition is a fundamental ecological interaction among plants, arising when species utilise the same limited resources such as light, water, nutrients, and space. Resource limitations reduce the growth and survival of less competitive species, altering ecosystem structure. In agroecosystems, weed–crop competition is a major challenge, reducing yield and quality. Weeds often exhibit greater adaptability and resource efficiency, enabling them to outcompete crops. Competition intensity is influenced by population density, morphology, phenology and survival strategies. Understanding plant competitive interactions is crucial for ecologists and agronomists to develop sustainable weed management and resource optimization strategies. Climate change further alters competitive dynamics, favoring resilient and plastic species. Mechanisms like allelopathy, aboveground and belowground competition and adaptive growth responses shape community structure. Strategies to reduce weed pressure include breeding competitive crops and integrating cultural practices such as optimal sowing density, narrow row spacing, and cover cropping. Future research should address plant responses to multiple simultaneous stressors, the ecological role of allelochemicals under varying conditions, and the genetic mechanisms of competitive adaptability. A comprehensive understanding of these interactions is essential for designing resilient, high-performing agroecosystems in changing environmental conditions.

The launch of a successful quality-oriented breeding program requires both mining the residual diversity in grain quality parameters contained in the elite, high-yielding breeding material with good agronomic performance and introgression of new germplasm, such as local landraces, with a high level of targeted quality parameters per se. This study analyzed the combining abilities of 31 maize landraces and two divergent inbred lines–testers (ZPL217 and ZPL-255/75-5) regarding the yield and protein, starch, and lipid content, assessed by Near Infrared Reflectance (NIR) spectroscopy as a fast, non-destructive, and cost-effective method. The general combining ability (GCA) defines the average behavior of genotype in hybrid combination, resulting from additive gene action, so positive GCA values of landraces AN13 and AN197 for protein, AN632 for lipids, and AN594 for starch content indicate that they can be valuable sources of the mentioned properties in quality-oriented maize breeding programs. The obtained correlation between starch content and protein and yield (−0.948 **; 0.587 **) pointed out that an increase in the protein content during breeding will be accompanied by a decrease in the starch content and yield. The specific combining ability (SCA) of the testers used, suggests their possible application in establishing and improving quality breeding programs’ initial material.

The narrow genetic base of commercial maize varieties emphasise the necessity for conservation, characterisation and utilisation of germplasm stored within gene banks. Broad genetic variability preserved in the Maize Research Institute Zemun Polje (MRIZP) gene bank, which includes accessions which originated from the Western Balkan, as a part of European corn-belt, is an exceptional source of desirable traits for enriching breeders' working collections for maize breeding under temperate conditions. Preliminary screening for abiotic stress tolerance, which marked 321 maize landraces, served as the first step in stratification process of selecting a smaller number of accessions from the entire gene bank local collection. After classification of these landraces into eleven homogenous groups, the objective of this study was to continue the stratification process of selection (as a second step), based on evaluation of agro-morphological traits of interest for breeding. The conducted evaluation highlighted 40 landraces with the best per se performances, important for breeding. Out of them, 28 early-maturing flint landraces with stiff stalks, low positioned ears, high yield potential and good general ear assessment could be considered as valuable source for their introgression into elite flint germplasm pool.

In a large number of plant species, including maize, different phenotypic traits have undergone major changes through the breeding process, resulting in the creation of varieties and hybrids of good agronomic performance. This study aimed to examine the variability of the plant height (PH) and plant height to the uppermost ear (EH) of maize top cross hybrids obtained from crossing 31 local landraces with three genetically divergent testers (L217, L73B013 and L255/75-5). Top cross hybrids were tested in a two-year experiment, at four locations, in two replicates. The grand mean of top cross hybrids for PH and EH were 255.8 cm and 101.8 cm. Analysis of variance showed that all sources of variation (environment - year × location (E), landrace (B), tester effect (A), as well as their interactions) were highly significant (p≤0.01), except for triple interaction (A × B × E). The coefficients of variation for the PH and EH were 4.76% and 8.87%. A highly significant correlation was found between the examined traits (r=0.785; p <0.01). Linear regression of PH and EH shows that the increase of EH by 0.5 cm is followed by the 1 cm of PH increase. Based on the results, the general combining ability (GCA) of landraces for the examined traits, is under the influence of the additive effect of genes, i.e. tall landraces per se in crosses with all three testers give tall hybrids and inversely. In maize production, a trait of interest is the small EH/PH ratio. Landraces MB1960, MB642 and MB1890 showed the best GCA for a given trait, so they can serve as sources of a given trait in pre-breeding programmes.

Introduction/purpose: This paper presents the results of several different research studies. The inbred lines ZPPL 146 and ZPPL 159 and the maize hybrids ZP 633, ZP 735, and ZP 737 are primarily intended for human and livestock nutrition. Their selection took about four decades. Methods: Spectral bands were registered using the method of resonant Raman spectroscopy of the leaves of inbred maize lines. These spectral bands indicate the conformational characteristics of not only carotenoid molecules but also other compounds (phosphate, gluten, and amide III) in the leaf. Results: A systematic examination of the inbred lines ZPPL 146 and ZPPL 159 and their maize hybrids ZP 633, ZP 735, and ZP 737 was performed in this paper. It was stated that the new inbred lines of corn, i.e. ZPPL 146 and ZPPL 159, are rich in carotenoids and yellow pigments. These lines also have significant quantities of other valuable bioactive compounds and good physical characteristics. The lines have an upright position of the top leaves and belong to the group of maize lines with significant characteristics of the photosynthetic model. They are resistant to high temperatures and are drought tolerant. Conclusion: This paper presents the relevant properties, characteristics and parameters of the new studied inbred maize lines that can be used in selection processes in the future. High-yielding and high-quality maize hybrids, i.e. ZP 633, ZP 735, and ZP 737, have been created from the mentioned inbred maize lines. They are recognizable by their qualities. The hybrid ZP633 is especially noteworthy for human consumption (children and the elderly). Further, from the agronomic-veterinary point of view, it is confirmed that the hybrids ZP 735 and ZP 737 are the most suitable for livestock feeding with the programmed use of corn silage. The relevant agronomic, morphological and nutritional properties of the maize hybrids ZP 633, ZP 735, and ZP 737 are also presented in this paper. The results regarding the grain structure and yield height for grain and silage for the hybrids ZP 677 and ZP 684, produced in Serbia and the countries of Southeastern Europe, are also given.

Improving the production of different cultivated plant species is of great importance for both human and animals, as well as for industrial processing. In the light of global climate changing and searching for renewable sources of energy, this task becomes even more important. Scientists from different areas of research, are actively involved in solving this complex task. Climate changes represent a big challenge not only for agricultural practices, but also for the process of shaping agricultural strategies. Recent studies indicate that climate changes can not be stopped. Constantly growing problems brought by global climate changes could be, to a larger extent, overcome by breeding programs, along with application of adequate agrotechnical measures. Thus, development of new varieties and hybrids with improved performances in response to more frequent and unfavorable environmental conditions, is of prime importance in breeding centers.