This paper analyzes the impact of genes and proportional contribution of parental genotypes on the inheritance of root yield and sugar content in diploid hybrids of sugar beet. The survey included two diploid male-sterile monogerm lines and three single (SC) male-sterile hybrids as maternal components, while three multigerm diploids were used as pollinators. The partitioning of genotypic variance into additive and dominant components was performed by half sibling (HS) and full sibling (FS) covariance. The proportional contribution of individual components of crossbreeding (lines, testers, and interactions) was exhibited in the expression of certain characteristics of F1 generation. Genotypic variance components showed a significant effect of nonadditive gene action (dominance) in the inheritance of root yield and sugar content, while the additive effect of genes was less significant. Maternal components had a greater proportional contribution to root yield, while lines, pollinators, and their interactions had an equal contribution to sugar content.

Advantages or disadvantages of intercropping system can estimate through expression of components of yield on the base of values of productive organs (spike, pod). The aim of this work was study of variation of spike index in cereals species and pods index in pea of spring intercropping. For investigation included spring species of small grains: wheat, triticale, oat and spring legume pea. The investigation was carried out in field condition in experiment with randomised block design of 5m 2 plots, with 4 replications. Each species (cereals and pea) were sown sole and in intercrops wheat+pea, triticale+pea and oat+pea. At the maturity stage used 40

The main goal of plant breeding is to improve quality traits, yield and resistance to abiotic and biotic stress factors. A thousand years ago, people selected the best plants, seeds or fruits to produce seed for new crops and food for human and animal nutrition. Modern plant breeding is based on genetic principles and contributes to increases in yield and quality components (contents of protein, amino acids, fat, sucrose, mineral elements etc.). Breeders in conventional breeding programs in the last six decades have made changes to plant phenotypes, significantly improved resistance to diseases, earliness, and frost and drought resistance, and improved scientific farming practices, baking and milling technologies, and beverage production technology. Through bioinformatics and improved technology, breeders have developed ways to improve and accelerate the breeding process to combine desired traits in new genotypes as well to operate at the level of individual cells and their chromosomes. Nowadays, modern biotechnology is used to improve human nutrition, and develop genotypes with significantly higher yields and quality compared with genotypes created by conventional breeding. By genetic modification it is possible to add, modify or delete a trait without interfering between two complete genomes. However, genetically modified crops can be used after their assessment in terms of human health, food safety and the environment.

Ruderal flora, as well as the vegetation that flora forms, represent an extremely dynamic floristic-vegetation complex and arean integral part of the most immediate living and working environment of human. It is formed and developed mainly in human settlements, as well as in the other anthropogenic environments that are occasionally or permanently under direct or indirect influence of various forms of human activity. Ruderal vegetation is found not only directly around the settlements, but also around all urban and accompanying facilities: along roads, paths and fences around houses, yards, walls and roofs, in avenues, on ruins, construction sites, landfills, along railway tracks, road and defense embankments, on wet and nitrified banks of rivers, near human settlements, in abandoned lawns, on the street walks with sandy areas, cemeteries, in degraded pastures, forests, etc. This essay presents the distribution and representation of economically harmful, invasive and quarantine weed species (Abutilon theophrasti, Agropyrumrepens, Amaranthusretroflexus, Calystegiasepium, Cirsiumarvense, Chenopodium album, Chenopodiumhybridum, Convolvulus arvensis, Cynodondactylon, Daturastramonium, Sonchusarvensis, Sorghum halepense, Xanthium strumarium…) at ten sites in the Nisava district. The assessment of species representation was done in two shootings (May and August) according to scale 1-4. The proper selection of herbicides depends, in a large extent, on the presence of dominant weed species and on the time of application.

The damage from the present weeds in maize crop is shown by the reduction of yield in almost every year and their suppression is completely economically justified. The right selection of herbicides mostly depends on the presence of dominant weed species and the time of application. The paper presents the distribution and existence of economically harmful, invasive and quarantine weed species (Abutilon theophrasti, Agropyrum repens, Amaranthus retroflexus, Ambrosia artemisiifolia, Capsela bursa-pastoris, Chenopodium album, Chenopodium hybridum, Cirsium arvense, Convolvulus arvensis, Datura stramonium, Avena fatua, Calystegia sepium, …) on ten locations of maize crops in the Nisava district. Estimation of the species presence was done in two shootings (May and August) on scale 1-4 (1 - species appears individually and occupy up to 5% of the surface, 2 - appears and occupies 5-25% of the surface, 3 - appears often and occupies 25-50% of the surface, 4 - the species prevails over the cultivated plant and occupies over 50% of the surface).