Effect of Soil Fertilizer,Foliar Fertilizer,and Growth Regulator Application on Milk Thistle Development,Seed Yield,and Silymarin Content

Abstract

An important consideration for milk thistle (Silybum marianum L.) cultivation is regulating development to lengthen the reproductive stage and increase seed yield with high silymarin content. The treatment of milk thistle with foliar fertilizers and growth regulators—thidiazuron (Dropp^®), 2,3,5‐triiodobenzoic acid (Tiba^®), mepiquat chloride (Pix^®), and prohexadione‐Ca (Regalis^®)—resulted in an increase in the proportion of mature flower heads. Highest seed yield was observed in plants treated with Pix^® and mineral soil fertilization, whereas in plants treated with foliar fertilizers, highest yields were observed with Pix^® and Regalis^®. The highest content of silymarin was found in plants treated with Dropp^® and foliar fertilizer. Generally, treatment of milk thistle with plant‐growth regulators in combination with soil or foliar mineral fertilizers increased the total amount of silymarin by increasing seed yield per hectare.