Physicochemical and fatty acid composition of spring canola seeds after treatment with biostimulants

This study evaluates the effects of foliar application of newly developed natural biostimulants on the physicochemical composition and fatty acid profile of seeds of spring oilseed rape (Brassica napus oleifera annua), hybrid “Lakritz”, grown under organic cultivation. During 2 consecutive harvest years, in precise field trials conducted accordingly randomized block design at the Institute of Agriculture and Seed Science “Obraztsov Chiflik” – Ruse, the influence of 3 biostimulants with different characteristics applied in 2 doses was tested. Biostimulants were developed at the Institute of Cryobiology and Food Technologies – Sofia, based on vermicompost extract (HA), chitosan (Cs) and a humic complex containing a naturally identical growth regulator of auxin-type (HAR). It has been established that the application of biostimulants in critical phenological phases leads to an increase in the content of crude proteins and crude fibers in the seeds. Treatment with Cs reduces the content of crude fats compared to the control group, while the influence of the humic extract and the humic complex was less pronounced in the first year. Crude fats increase in the second year of treatment when using the preparations HA 600, HAR 300 and HAR 600. The studied biostimulants improved the fatty acid composition of rapeseed seeds by reducing the total content of undesirable saturated fatty acids (Cs 300, Cs 600, HAR 300, and HAR 600) and erucic acid (Cs 600 and HAR 600), while increasing desirable polyunsaturated fatty acids, thereby enhancing the health properties of rapeseed oil.