EFFECT OF NITROGEN FERTILIZATION ON YIELD AND QUALITY OF MILK THISTLE [SILYBUM MARIANUM L. (GAERTN.)] ACHENES

Milk thistle is cultivated especially for the medical substance called the silymarin complex, which can be used in human medicine and in animal nutrition. The composition of this complex depends on many factors and one of these factors is fertilization. This aim of this study was to determine the effect of nitrogen fertilization on the yield and quality of milk thistle achenes. A pot experiment was established and the milk thistle cultivar Mirel was used as a model crop. The effect of four variants of nitrogen fertilization (lower and higher single doses, lower and higher split doses) was observed. The observing parameters were the content of macronutrients in aerial vegetative mass, height, weight and dry matter weight of milk thistle plants, number of inflorescences and achenes per plant, 1000 achenes weight, yield of achenes per plant and content of the silymarin complex in achenes. The variant with a higher single dose of N showed the significantly highest number of achenes (254.5) and yield of achenes (7.9 g per plant). The significantly highest number of mature inflorescences (2.5 per plant) was found in variants with single doses of N. Nitrogen fertilization slightly modified the content of silymarin complex constituents in achenes. The highest content of silybin was in the variant with a higher split dose of N, while the significantly highest content of silychristin was in the variant with a lower single dose. Plants from the variant with a higher single dose had a significantly higher content of silychristin and isosilybin than the control variant. The total content of the silymarin complex in achenes was increased only in the variant with a higher split dose of nitrogen (higher by about 6% in comparison with the control).