Abstract
Maize (Zea mays L.) is one of the most widely cultivated crops globally. The growing demand for grain and silage requires the intensification of the production process. Maize’s cultivation as a monoculture ensures higher income per unit area and is therefore a preferred practice. An increasing share of the market is occupied by hybrids developed using the Duo System technology. Through an introduced gene for tolerance to cycloxydim an effective control of both annual and perennial grass weeds in maize crops is ensured. During the period of 2024-2025 a field trial for evaluating the effect of mono-cropping and crop rotation on phenology and yield components of three Duo System maize hybrids – Zanetixx DUO, Hexxagone DUO and Elaraxx DUO, was conducted. The research was conducted in the experimental base of the department of “Agriculture and Herbology” of the Agricultural University of Plovdiv, Bulgaria under irrigation. The phenological development of the hybrids was monitored under conditions of two cropping systems: monoculture and crop rotation with winter wheat. Twenty representative plants from each variant were marked and observed throughout the growing season in order to determine the maize hybrids phenological stages and their duration as following: emergence; 3-5 leaf stage; 9-10 leaf stage; tasseling; milk, dough and full maturity stages. For the purposes of the trial a structural analysis of the harvested yield was conducted. While in the first year the yields did not differ significantly, in the second year a negative effect was found as a result of the monoculture cultivation.
Keywords: cycloxydim, hybrids, maize, preceding crop, yield