Influence of crop density on the productivity of some sunflower hybrids (Helianthus annuus L.) in the conditions of Dobrudzha
Mariyana Stoeva1 • Petar Yankov2
1Dobrudzha Agricultural Institute - General Toshevo, 9521, General Toshevo, Bulgaria
2Technical University - Varna, Department of Plant Production, 9010, Varna, Bulgaria
The study was carried out on the land of the Dobrudzha Agricultural Institute - General Toshevo in the period 2020-2021. The experiment is based on the method of fractional plots, in threefold repeatability of the variants and the size of the harvest plot of 20 m2. The tillage and weed control are carried out using the traditional technology of growing the crop for the conditions of the area. Sunflower hybrids were fertilized with 6 kg N/da and 12 kg P2O5/da. The sowing was done mechanized with a planter for precise sowing at a sowing rate of 5000, 6500 and 8000 plants per decare. The hybrids Deveda (conventional linoleic hybrid), Enigma CLP (imi-resistant hybrid), Dara (sulfo-resistant hybrid) both breeding of DZI - Gen. Toshevo and P64HE144 (high oleic hybrid) from Pioneer (Corteva Agriscience) were selected for the study. Seed yield in Deveda and P64HE144 hybrids increases with increasing crop density. The Dara hybrid has the highest productivity at 5000 plants per da. Seed yield in Enigma hybrid is relatively the same in the studied crop densities.