The effect of colour grading of milk thistle (Silybum marianum (L.) Gaertn.) seeds on their quality for sowing
Introduction: Milk thistle (Silybum marianum (L.) Gaertn.) is a medicinal plant belonging to Asteraceae family. Extract from milk thistle achenes (termed in practice as seeds) contains sylimarin, which protects liver cells against inorganic and organic toxic compounds. Objective: The aim of the research was to evaluate the effect of colour grading on the quality of milk thistle seeds. Methods: Seeds were graded manually by colour according to the Royal Horticultural Society Colour Chart, issued in Great Britain. In three samples two fractions of seeds were separated: beige and brown, whereas seeds of the fourth sample were graded into three fractions: yellow, beige and brown. The 1000-seed weight and germination of graded and non-graded seeds were evaluated. Infestation of graded seeds with fungi was assessed. Results: Brown seeds had a higher 1000-seed weight than beige or yellow ones. Germination at the final count of beige seeds did not differ as compared to that of brown seeds or was even better. Milk thistle seeds were infested with numerous fungi, however Alternaria alternata and Ulocladium consortiale predominated. Conclusions: Less mature beige seeds can be used as sowing material because their germination at the final count did not differ as compared to that of fully mature brown seeds or was even better. Infestation of these seeds with some of the fungi was lower than brown seeds.