The Effect of Fertilization with Sulphur, Boron, and Amino Acids on the Content of Glucosinolate in Winter Rape Seeds

Abstract

The study was carried out in 2016–2019 at the Zawady Agricultural Experimental Station (52°03’ N and 22°33’ E) belonging to the University of Natural Sciences and Humanities in Siedlce, in Poland. The field experiment was established in a split-plot design with three replicates. The studied factors were: I. Three winter rape morphotypes: population morphotype (Monolit variety); restored morphotype with traditional growth type (PT248 variety); restored morphotype with a semi-dwarf growth type (PX115 variety); II. Types of foliar nutrition: (1) control variant—sprayed with water, without foliar nutrition and amino acids; (2) biostimulant Aminoplant; (3) foliar fertilizer Siarkomag + foliar fertilizer Bormax; (4) foliar fertilizer Siarkomag + foliar fertilizer Bormax + biostimulant Aminoplant. The aim of the study was to determine the effect of foliar application of sulphur, boron, and amino acids on the content of glucosinolates in seeds of three winter rape morphotypes (Monolit, PX115, and PT248). The foliar feeding applied reduced the feed value of winter rape seeds. On treatments (2, 4), where only amino acids were used or in addition in combination with sulphur and boron, the increase in glucosinolate concentration (GLS) was the largest. Regardless of the type of foliar fertilization used, the Monolit variety contained the lowest concentration of these compounds. The content of glucosinolates in rapeseeds of the studied cultivars varied during the years of the experiment. Studies have shown that the value of this feature increased with the growth of water stress occurring before harvest.