Boron is one of the most important nutrients required for the growth and development of plants. However, boron deficiency or excess also affects the physiological development of plants such as germination and seedling development. In this study, the effects of boron applications of 0-8 ml L-1 (4 concentrations) in 2 linseed cultivars [Beyaz Gelin (C1) and Sarı Dane (C2)] were investigated under laboratory conditions. In the study; germination percentage (GP), mean germination time (MGT), seeding length (SL), root length (RL), seedling fresh weight (SFW), seedling dry weight (SDW), root fresh weight (RFW), root dry weight (RDW) and relative water content (RWC) parameters were examined. As a result of the study, it has been determined that there are decreases in the properties of the cultivars in terms of the parameters examined with boron applications. It has been determined that especially 8 mg L-1 application has a toxic effect and prevents seedling and root development.