No abstract

The aim of the research was to study the response of various flax genotypes to the treatment of plants with a sulfonylurea herbicide – Magnum (active ingredient is metsulfuron-methyl) and to identify resistant forms for use in breeding programs for herbicide resistance. In 2018-2020 an assessment of 24 varieties and promising lines of fiber flax of domestic and foreign selection for resistance to this herbicide was carried out, the treatment of crops with the preparation was carried out at the recommended consumption rate of 0.01 kg/ha in the “herringbone” phase. It has been proved that the use of this herbicide leads to uneven plant growth during the “herringbone – flowering” period, which negatively affects the yield and quality of flax fiber. The decrease in the main indicators of the productivity and quality of the fiber in the variant with the use of the herbicide in comparison with the control, depending on the genotype was: in plant height – up to 44.4 %, in the weight of the technical part – 71.1 %, in the fiber mass – 74.8 %, in «myklost» (the ratio of the technical length of stem to its diameter)– 46.3 %, in the length of the elementary fiber – 27.7 %. A high level of resistance (over 80 %) to the herbicide Magnum for all analyzed traits was shown by the varieties Atlant (Russia) and Mogilevsky (Belarus). It was shown that when treating fiber flax plants with the herbicide, as a rule, an increase in inflorescence occurs due to a decrease in the technical length of the stem. It results in rise of the main indicators of seed productivity in most of genotypes under the influence of the Magnum preparation – the number of bolls and seeds per plant (up to 3.2 times). The exception was the variety Vega 2 (Lithuania), which had a decrease in the number of bolls per plant in the variant with herbicide treatment compared with the control by 1.8 times, and in the number of seeds by 5.3 times. This varietywasalso the most sensitive to the effect of Magnum in all parameters of productivity and fiber quality. The results are consistent with the data obtained whentreating various collection samples of fiber flax with a tank mixture Magnum + Herbitox L + Miura at the recommended consumption rates (0.007 + 0.6 + 1.0 kg(l)/ha).