Selectivity and stability of herbicides, herbicide tank mixtures and herbicide combinations on seed yield of Clearfield oilseed canola (Brassica napus L.)

G. Delchev*

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 31 May 2021; accepted for publication 26 July 2021)

Abstract. During the period 2018-2020 a field experiment was carried out with the winter Clearfield oilseed canola hybrid Phoenix CL (Brassica napus L). Factor A included the years of investigation. Factor B included untreated control, 2 combined herbicides: Cleranda SC and Cleravo SC; 6 herbicide tank mixtures: Electron 500 SC + Maza 4 SL, Springbok + Maza 4 SL, Tanaris + Maza 4 SL, Butisan max + Maza 4 SL, Cliofar 600 SL + Maza 4 SL and Galera super + Maza 4 SL; 6 herbicide combinations: Caliph 480 ЕC + Maza 4 SL, Caliph mega + Maza 4 SL, Bismark CS + Maza 4 SL, Nero ЕC + Maza 4 SL, Brasan 540 EC + Maza 4 SL and Colsor trio ЕC + Maza 4 SL. Herbicides Cleranda, Cleravo and Maza were used in addition with adjuvant Dash HC. Foliar-applied herbicides were treated during 2-4 leaf canola stage. Soil-applied combined herbicides were treated during after sowing before emergence period of the canola. It was found that: (i) the highest seed yields are obtained by use of combined herbicide Cleranda, followed by herbicide tank mixture Electron + Maza and combined herbicide Cleravo; (ii) the high canola yields are also obtained by herbicide tank mixtures Butizan max + Maza, Springbok + Maza, Tanaris + Maza, as well as by herbicide combinations Caliph mega + Maza, Brasan + Maza, Bismarck + Maza; (iii) technologically the most valuable are combined herbicide Cleranda, followed by herbicide tank mixture Electron + Maza and combined herbicide Cleravo; (iv) in terms of technology for growing winter Clearfield oilseed canola, herbicide tank mixtures Springbok + Maza, Butisan max + Maza and Tanaris + Maza, as well as herbicide combinations Caliph mega + Maza, Bismar + Maza and, Nero + Maza get high rating; herbicide tank mixtures Cliofar + Maza and Galera super + Maza and herbicide combinations Caliph + Maza and Colsor trio + Maza get low rating.