Effect of plant density and N-fertilizer on seed vigour and some related indices in milk thistle (Silybum marianum. L)

To study the effects of plant density and N-fertilizer on seed vigour of milk thistle (Silybum marianum) an experiment was conducted in 2005 at research station of Hammand Absard. The harvested seeds were stored in a suitable place for a year, then they were used for measuring of seed vigour, mean daily germination, mean time of germination, seedling vigour index (calculated by seedling dry weight and seedling length), electrical conductivity, cold test and accelerated ageing test. The results indicated that with increasing the mother plants growth achieved by decreasing the plant density and increasing of N-fertilizer, the seeds vigour increased. It had also a positive effect on mean daily germination, mean time of germination, seedling vigour index and decreasing the electrical conductivity of seeds. There was a positive correlation between increasing of the seed power against cold, heat and water stress and improving of the mothers plant growth.