Effect of Different Priming Treatments on Quality of Long-Term Stored Seeds of Apium graveolens var. rapaceum DC

In order to improve germplasm preservation of local cultivar “Friulano”, belonging to Apium graveolens var. rapaceum (Miller) Gaudin) seed germination of a seed lot, stored for prolonged time at -20°C, was assessed in comparison to that of a commercial cultivar. In order to increase the seed performance during germination, three different priming pretreatments (hydropriming for 24 h, osmopriming for 24 h, and osmopriming for 7 days) were performed. Additionally, seed sowing was undertaken on both potting soil and Petri dish plate condition. Analysis of seed quality was estimated by measurement of germination percentage, germination energy and the time to reach the 50% of full germination (T50). The results evidenced that conservation of celeriac dried seeds of “Friulano” cultivar at -20°C for one year maintained a good level of seed germination (ranging from 38% to 53%), not statistically diverse from the that of commercial cultivar, for both short hydro- and osmopriming treatments. The germination percentage increased when primed seeds have been treated in Petri dishes (up to 70%-80%). Furthermore, osmopriming for 24 h positively affected the germination energy, similarly to that observed in commercial cultivar, being statistically higher compared to hydropriming- and prolonged osmopriming-treated samples. Accordingly, T50 in short osmopriming treated seeds was low, indicating that this treatment induced a rapid and uniform germination, being most of the seeds germinated within one week. In conclusion, these findings represent an important informative step in amelioration of ex situ conservation of a rare autochthonous horticultural cultivar in North-eastern of Italy.