Five sunflower hybrids (Albena, Super Start, Zora, Santafe and San Luka) and their parental lines (2607, 1234, 1607 were tested on a block design in four replication in the course of two years. The highest phenotypic and genotypic coefficients of variation were recorded for seed yield per plant followed by the number of seeds per plant and 1000 seed weight, while the lowest value was observed at 50% flowering. The heritability coefficients in a broad sense were high in all characters and ranged from 69.74 % to 96.96 %. Correlation between the main quantitative characters found a positive correlation with the seed yield per plant. Oil content was lower but not significantly correlated concerning the head diameter, the 1000-seed weight, the plant height, the stem diameter and the days to 50% flowering.

A comparative experiment was carried out with five Bulgarian and five foreign durum wheat cultivars. The aim of the experiment was to determine the chemical content and grain technological quality of some Bulgarian and foreign durum wheat cultivars grown under the agriecological conditions of Southern Bulgaria. The Vazhod cultivar proved to give the highest durum wheat grain yield, followed by Beloslava cultivar. Out of the foreign durum wheat cultivars the Durumko was notable for its higher productivity. The crude protein content in the grain was highest in Zagorka, Yavor and Yukon. The highest yield of gluten was reported in Beloslava, Vazhod and Zagorka.

Heavy‐metal soil pollution is a common environmental problem all over the world. In the induced phytoextraction process plants can transport and translocate to their above‐ground tissues significant concentration of contaminants. Since some heavy metals are mostly presented in non‐soluble state, the application of chelating agents is needed. In this study we introduced into the rhizosphere of maize (var. Kneja 530) and sunflower (var. Favorit) plants 1 and 5 mmol l−1 of EDDS and NTA, and 5 g kg−1 of nutrients to enhance the accumulated concentrations of cadmium, lead and zinc. The fraction of CaCl2‐extractable metals increased incrementing the concentration of chelates. This was clearly pronounced for all the metals in the treatments with NTA and for Pb in those with EDDS. Generally, under all the experimental conditions the accumulated heavy‐metal concentrations were found to be significantly higher than in the control. Thus, in the case of higher concentration of NTA and EDDS, the accumulated Cd in the leaves of sunflower was found to be threefold higher. The highest accumulation of Pb in the leaves of maize was observed when nutrients were added (62 mg kg−1). On the other hand, negative effects of the used chelating agents on soil bacteria and fungi at plant harvest were not observed. Moreover, when nutrients were added, the number of studied microorganisms significantly increased.

SUMMARYInvestigations conducted during last years showed serious violations of ecological equilibrium in many agricultural regions.Crops produced in these regions are commonly used as food and feed. It has been established that the content of heavy metals in the soils and agricultural crops grown nearby the metallurgical factories is much above the admissible concentration. Micro-particles of Pb, Cu, Zn and Cd separated in the atmosphere by aerosols, accumulate in the soil, plants and water areas. From the studied heavy metals the coarse particles of Zn commonly pile in soil nearby the contaminator, and the heavier particles of Pb are distributed by the prevailing winds. These elements accumulate shallow in the upper layer and confined to quantity move down. The irregular contamination of soil around certain factory is in great part dependent on turbulent movement of air, windlessness and the condition of fluctuating atmosphere - inversion. Contamination with heavy metals is most oftenly in according with areas. Maximum accumulation is found out on boundary areas in a distance at about 1000 m from the factory called the area of accumulation, and 15 000 m away from the factory called area of distraction. Commonly, on this area is grown one of the specific for Bulgaria culture - the sunflower. This needs solving of many problems connected with studying the accumulation and depous of localization of heavy metals in sunflower grown on contaminated soil, as well as their influence upon soil fertility.

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