The effect of salinity on seed yield and oil of Silybum marianum (L.) Gaertn

Milk thistle [Silybum marianum (L.) Gaertn] is an annual or biennial plant, native to the Mediterranean area, which has spread in north and south of Iran. A fruit of milk thistle contains a relatively high amount (approx. 20%) of oil, which exhibits wound-healing, anti-burn, and hepatoprotective properties. Experimental: In this research, a pot experiment was conducted using a completely randomized design with seven level of salinities [1.09(control), 3, 6, 9, 12, and 15 dS/m] for two genotypes, Ahvaz wild type and cultivated German origin (Royston). At the harvest, the results have showed that both genotypes grow satisfactorily and had a normal size in soils up to salinity of 9 dS/m, compared to the control plants. However, growth parameters such as number of capitula per plant, main shoot capitulum's diameter, and seed yield and yield components per plant was reduced with salinity greater than 9dS/m in both genotypes. The seed oil content reduced with salinity greater than 9 dS/m slightly. Industrial and practical recommendations: Our results suggested that both types of milk thistle could survive salinity up to 15 dS/m and produced seeds but maximum yield seed get in up to 9 dS/m. Growing milk thistle in low fertile soil and under moderate salinity (≤9.0 dS/m) conditions could be important not only such as a cover crop against soil erosions but also for producing seeds of greater value for medicinal and nutrition purposes