Agronomic characterization of some spontaneous genotypes of milk thistle (Silybum marianum L. Gaertn.) in mediterranean environment

Spontaneous populations of Silybum marianum L. of three environments were evaluated for their biological and productive traits. Despite the different environmental conditions of the studied sites (hill and plane), a there was a general uniformity in the main observed plant traits. Hilly environments produced a higher number of secondary flower heads compared with the plane site. Seeds in the secondary flower heads had a conspicuously lower weight (-56%) when compared to the primary ones. Plant height and height of the first branch insertion was positively related, directly or indirectly, to the seed yield. A first approach for the definition of an ideotype is proposed.