Influence of seeding rate on yield and oil output of spring rapeseed, cultivated no-till technology, was assessed in 2023-2025 field experiment, conducted on leached chernozem of Muslyumovskiy District of the Republic of Tatarstan. Kyurri and Kultus hybrids were studied at seeding rates of 500, 600, 700, and 800 thousand viable seeds/ha in a two-factor design with four replicates. Weather conditions during the study years formed a contrasting series in moisture availability and temperature regime, which made it possible to evaluate the stability of technological solutions. The average yield in the experiment increased from 3.22 t/ha in 2023 to 3.42 t/ha in 2024 and 3.90 t/ha in 2025; Kyurri hybrid had an average yield advantage (3.57 t/ha) compared to Kultus (3.46 t/ha). The response to the seeding rate varied: for Kyurri, yield growth was maintained with an increase in the rate to 700-800 thousand seeds/ha, while for Kultus, the maximum was recorded at 600 thousand seeds/ha and decreased at 700-800 thousand seeds/ha. The average seed oil content was higher at 600-700 thousand seeds/ha; for Kyurri, the maximum average value was 600 thousand seeds/ha (44.00%). Gross oil yield as an integral performance criterion (yield × oil content) showed an optimum of 700 thousand viable seeds/ha for Kyurri (1.585 kg/ha) and 600 thousand viable seeds/ha for Kultus (1.545 kg/ha); for Kultus, at 700-800 thousand seeds/ha, a risk of decreased oil yield was identified in some years. The obtained data provide a regionally verified justification for seeding rates for modern rapeseed hybrids in the no-till system on leached chernozems of the Republic of Tatarstan, with a focus on maximizing oil yield.
Motovalov et al. (Wed,) studied this question.