Classification and breaking methods of galbanum(Ferula gummosa BIOSS)seeddormancy

Galbanum (Ferula gummosa BIOSS) is a medicinal, commercial and industrial plant in Iran but its cultivation is restricted by seed dormancy. Therefore, a study was conducted to determine class and environmental requirements for breaking of seed dormancy. During imbibition study, both scarified and intact seeds exhibited similar pattern in water uptake and it seems there is not physical dormancy. Moreover, excised embryos from dormant seeds did not germinate in MS medium, therefore there was not mechanical dormancy. Cold stratification (3˚C) for 75 days reduced seed dormancy (germination percentage increased up to 94%). Increment in stratification temperature reduced dormancy, as cold stratified seeds for 75 days had 50 and 35% germination in 6 and 10˚C, respectively. Stratification of seeds in alternative temperatures increased seed germination, but storing wet seeds in high temperatures for long time caused seed deterioration and decreased seed viability. Thus, the longest time in which seeds can be stored at high temperature (20 ˚C) is 30 days and seeds start to deteriorate after this time. The best condition for dormancy breaking was alternative temperatures (60/30 days, hot-cold) which resulted in 87% germination. It was shown that embryo grows during cold stratification. According to the results, galbanum seed dormancy is classified as Deep-Complex Morphophysiological dormancy.