Agroecological assessment of spring rapeseed varieties in forest-steppe conditions of the Middle Volga region

The article presents an agroecological assessment of spring rapeseed varieties for productivity and adaptability in the forest-steppe conditions of the Middle Volga region. The object of research was 14 varieties of spring rapeseed of domestic and foreign selection. The experiment was carried out in 2020-2023 on the fields of the FSBRI. Meteorological conditions during the years of research were contrasting. The hydrothermal coefficient varied from 0.70 (2020) to 1.24 (2022). On average for 2020-2023, the yield of spring rapeseed varieties was quite high and varied between 1.67-1.86 t/ha. The highest productivity was observed in the varieties Ruyan (1.86 t/ha), Rif (1.84 t/ha), Sibiryak-60 (1.83 t/ha), Ability (1.82 t/ha) and Novosel (1.81 t/ha). These varieties were 0.14-0.19 t/ha higher than the standard variety Galant. The variability in the yield of varieties over the years was average, the coefficient of variation was 3.16-12.34%. The varieties Erebus (Cv = 12.34%) and Nadezhny 92 (Cv = 11.81 %) were characterized by the greatest variation in yield. The most stable varieties over the years were Novosel and Galant, the coefficient of variation of which was 3.46 and 3.16 %. The highest oil content was observed in the Tavrion (46.9 %) and Ruyan (46.6 %) varieties; the increase relative to the standard was 5.2 and 4.9 %. The content of erucic acid remained quite low and varied from 0.06 % in the Duke variety to 2.35 % in the Nadezhny 92 variety. The highest content of oleic acid (65.42 and 65.77 %) was observed in the Tavrion and Ruyan varieties. High environmental sustainability was noted in the varieties Novosel (-0.15) and Galant (-0.12), high genetic flexibility - in the varieties Rif (1.89) and Ruyan (1.87 t/ha). These varieties have a high level of stability (110.2 and 111.4), which indicates their ability to maintain a consistently high level of yield in different climatic conditions. All studied varieties had high agronomic stability (87.66-96.84 %) and a coefficient of responsiveness to improving growing conditions (1.08-1.33). The varieties Ruyan, Rif, Sibiryak-60, Novosel, Neman and Ability have a high degree of agroecological adaptability, which characterizes their resistance to changing environmental factors and responsiveness to improved agroclimatic conditions.