Effects of planting season and population type on quantitative and qualitative performance of Milk Thistle (Silybum marianum L.)

This study was aimed to evaluate the quantitative and qualitative performance of different populations of Milk Thistle (Silybum marianum L.( under the influence of autumn and spring planting season. Therefore, a split plot experiment was conducted including autumn and spring planting as main plots and four local populations (Shush, Poldoktar, Khoram Abad and Aleshtar) and a crop cultivar as sub plots. The study was carried out in the Faculty of Agriculture, Lorestan University, for two years 2014-2015. In addition, the native and crop populations of this species in Aleshtar were compared in a randomized complete block design. Based on the results, there was a significant difference between spring and autumn planting seasons. The highest plant height (107 cm), capitol diameter (44 mm), number of grains in capitol (78) and grain yield (1000 kg ha-1) were obtained in autumn planting. The interaction effect of planting season and population type showed that the highest content of silymarin (22 mg/g of dry weight) and silybin (3.9 mg /g of dry weight) was obtained from the crop cultivar in autumn planting. The comparison between native and crop populations in Aleshtar region showed that the highest content of silybin (4.2 mg /g of dry weight) and silymarin (more than 21 mg / g of dry weight) was recorded for native Aleshtar population compared with other populations. In general, it was determined that the highest and lowest quantitative and qualitative performance of Milk Thistle in the temperate region of Khorramabad was obtained in autumn planting, and the highest content of silymarin and silybin was recorded for the native Aleshtar population compared with other populations.