G. Delchev

Abstract. The research was conducted during 2008–2010 in Field Crops Institute, Chirpan, Bulgaria. The influence of 8 different herbicides and tank mixtures on durum wheat was studied with the participation of 4 new products: Palace 75 WG – 200 and 250 g/ha, Axial 050 EC – 600 and 900 ml/ha, Axial one – 1 l/ha and Traxos 045 EC – 1.30 l/ha. Hussar max WG – 250 g/ha was used as standard for herbicide with mixed spectrum. Puma super EB 7.5 – 1 l/ha, Grasp 25 EC – 1.2 l/ha and Topic 080 EC – 450 l/ha were used as standards for antigrass herbicides. Since some of these herbicides do not have an anti-broad-leaf effect, a new anti-broad-leaf herbicide Derby super at dose of 33 g/ha was used as partnering product of these herbicides. All of herbicides and their tank mixtures wereapplied in tillering stage of durum wheat. The highest grain yield was obtained by tank mixture Palace + Derby super. It has the highest herbicide efficacy and strongest initial effect against weeds. High grain yields are obtained when combining antigrass herbicides Traxos, Topic, Grasp and Puma super with antibroad- leaf herbicide Derby super, as well as separate use of combined herbicides Axial one and Hussar max. Differences in grain yields between these variants are not mathematically proven. Changes in grain yield are mainly due to changes in the grain number per spike and grain weight per spike of durum wheat. The use of investigated herbicides and tank mixtures between antigrass and anti-broad-leaf herbicides does not lead to negative changes in physical properties of durum wheat grain and in sowing properties of durum wheat sowing-seeds.