( I ) Unvernalized seeds were sown on November and soon after the sowing, the material plants, selected from the variety groups which differed from each other by ecological characteristics such as spring and winter habit of growth and photoperiodic response after vernalization, were treated for 50 days with differerit temperatures and photoperiods, Then all the materials transfered to the green house with 24 hour photoperiod and their heading behavior was recorded.
