Varietal features of crop structure elements formation and yield of oilseed flax in the conditions of Western Siberia

From 2022 to 2024, a number of economically valuable traits in six oilseed flax varieties recommended for cultivation in the West Siberian region: Severny, Chibis, Yantar, Avgust, Azurit, and Amber, were assessed on meadow-chernozem soil at the experimental farm of the Omsk State Agrarian University named after P.A. Stolypin. Over the three years of research, the shortest growing season of 92-94 days was observed for the Severny, Avgust, and Azurit varieties, while the longest, 103 days, was observed for Amber. For the Yantar and Chibis varieties, this figure was 96 days. The Chibis variety had the highest plant density (448.5 pcs/m2), exceeding other varieties by 0.6–2.3 pcs., but the best plant counts before harvest were demonstrated by the Avgust and Amber varieties (376.3–376.8 pcs/m2). Plant survival before harvest was 83.2–84.2% depending on the variety studied. Oilseed flax yield is determined by such structural elements as the number of capsules per plant, the number of seeds per capsule, and the thousand-seed weight. In terms of large-seed capacity, the control varieties Severny and Avgust were the undisputed leaders throughout all years of observation – 6.84–8.14 g, while the Amber variety had the lowest thousand-seed weight – 4.82–5.77 grams. It was found that in the soil and climatic conditions of the southern forest-steppe of Western Siberia, when using adaptive (environmental plasticity index greater than 1) and early maturing (vegetation period 92–93 days) varieties of oilseed flax Avgust and Azurit, it is possible to obtain over 1.8–1.9 t/ha of seeds with an oil content level of 49.8–50.1%, which will ensure a fat yield per unit area of about 939.9–965.4 kilograms.