Khosro Azizi - Associate Professor, Department of Agronomy, Faculty of Agriculture, University of Lorestan
Jamshid Nazari Alam - Doctoral student in ecology crop of Lorestan University
Mohammad Faizian - Associate Professor, Department of Soil Science, Faculty of Agriculture, University of Lorestan
Rouhollah Heydari - Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, PO Box ۶۸۱۴۹-۸۹۴۶۸, Khorramabad, Iran

Populations, planting area and density has a significant influence on the various properties of the Milk Thistle. Thus, the effect of Planting area on the four indigenous populations collected from (Shush, poldoktar, Khorramabad and Alashtar) and a crop cultivar were evaluated in the temperate (Khorramabad) and cold (Aleshtar) zone as a randomized complete block design. Also three densities of 6066, 80,000 and 100,000 plants per hectare as subplots and populations of Milk thistle as the main plot were evaluated in a split plot design for two years from 2014-2015. The results showed that Planting area had significant impact on traits such as plant height, grain yield and the silybin active ingredient, but had no significant effect on the other traits. Results of the interaction effects showed that The highest rate of silymarin (21.3 mg.g) and silybin (4.2 mg.g) was obtained in indigenous population of Alashtar and in cold region. The Grain yield in cold regions of Alashtar (0.72 T.ha) and in Khorramabad temperate zone (0.59 T.ha) That had significant difference together. biological yield of Different population was not affected by growth region. The highest plant height, grain and biological yield was obtained at density of 80,000 plants per hectare. With the increasing of density, the grain yield increased at first and then it decreased but it had no effect on the amount of silymarin.

Silymarin, Weather Conditions, Density