Photosynthesis parameters and productivity of crambe abyssinica when using growth regulators

The article presents an assessment of the formation of photosynthetic activity of crambe abyssinica and its productivity depending on foliar feeding with growth regulators to optimize the elements of its cultivation technology in the forest-steppe conditions of the Middle Volga region. Experimental work was carried out in 2021–2023. The object of research was the crambe abyssinica variety Demetra. The experimental design included the following options: control (without treatment); Blackjack (1.0 l/ha); Humate K/Na (1.0 l/ha); Zircon (1.0 l/ha); Albit (0.5 l/ha). The study conditions were different, the GTC varied from 0.80 to 1.29. Foliar treatment with preparations was carried out at the beginning of the budding phase of the crop. The use of growth regulators had a positive effect on the photosynthetic activity of crambe crops. Their use contributed to an increase in the assimilation surface area by 6.2…8.9 thousand m²/ha, photosynthetic potential by 0.3…0.5 thousand m² × day/ha, net photosynthetic productivity by 0.3…1, 5 g/m² × day and leaf surface index by 0.17…0.35 compared with the control. The largest area of leaves was formed during the flowering phase of crambe and was noted in variants with foliar treatment with the regulators Blackjack and Humate K/Na (69.1 and 70.3 thousand m²/ha). The maximum value of photosynthetic potential was noted in the variant with the use of Humate K/Na (3.40 million m²/ha × day). The highest indicator of net photosynthetic productivity (4.95 g/m² × day) was observed in the variant treated with Zircon. The greatest increase in this parameter was observed against the background of the Zircon and Blackjack regulators, which amounted to 2.44. The coefficient of PAR use by crambe plants was 1.28…1.78 % depending on the treatment used, with 1.16 % in the control variant. The average crambe yield for 2021–2023 was 1.69…1.98 t/ha. The use of growth regulators contributed to a significant increase in yield, the increase was 0.21…0.29 t/ha. The most effective were the Zircon and Blackjack regulators, the use of which ensured the formation of the highest seed yield – 1.98 and 1.94 t/ha, respectively.