The effect of brassinosteroide on germination parameters of mother seeds of safflower under drought tension

In order to investigate the effect of water deficit tension on mother plant, on vigor and seedling emergence rate percentage of safflower cultivars, the present research was conducted in split plot factorial with randomized complete blocks design with three replications at research farm of Faculty of Agriculture, University of Mohaghegh Ardabili in 2014. Treatments at the main plots included water tension (main plot) in three irrigation levels after 80 millimeter (normal irrigation); 120 millimeter (moderate tension); 160 millimeter (sever tension) evaporation from evaporation pan class A and sub plot included three cultivars of spring safflower (Goldasht, Sina and Faraman) and growth regulator on Brassinosteroid (no consumption and consumption of 10 -7 molar). The results showed that drought tension decreased one-thousand seed weight, percentage and speed of germination, length (radicle, plumule, and seedling), seedling dry weight and seedling vigor index, so that it dropped compared to normal level 14/34%, 79/87%, 66/11%, 30/92%, 34/55%, 32/60% and 48/55%. And among cultivars, Goldasht cultivar had the highest one-thousand seed weight, seedling dry weight, rate and percentage of germination, rootlet length and seedling vigor index. But treatment of brassinosteroide just caused significant increase in one-thousand seed weight and seedling dry weight. For other researchers, it is recommended to use bradycinosteroids at the grading stage. Because the effect of brassinosteroid is likely to decrease over time from flowering to seeding.