M. Koleva*, M. Radevska Field Crops Institute, 6200 Chirpan, Bulgaria (Manuscript received 14 August 2021; accepted for publication 26 October 2021) Abstract. Seeds of five Bulgarian cotton varieties, stored for one and two years, were subjected to five pre-sowing electromagnetic trea

P. Yankov Abstract. The investigation was carried out during 2004-2006 in the trial field of Dobrudzha Agricultural Institute on slightly leached chernozem soil. In a stationary field trial, 24 systems for soil tillage based on different soil tillage tools and operations were tested.

M. Drumeva, N. Nenova, E. Penchev Abstract. Sunflower, being one of the main oil seed crops in the world, is of special economic importance in East Europe. In sunflower breeding the heterosis effect is primarily used. The high yield and the quality properties of seeds depend on the in