Seed germination of five sage species (Salvia sp.) of populations native to Greece

In the present study, the effect of seed pretreatment and incubation temperature, on seed germination rate of five Mediterranean sage species S. fruticosa, S. officinalis, S. pomifera ssp. pomifera, S. ringens and S. tomentosa was examined. Seeds of all five species were collected from native populations in August 2019 and stored at room conditions, in darkness, for 5 months. The seeds were placed for germination at constant temperatures of 10, 15, 20 and 25 degrees C, under darkness, either without pretreatment (control) or after chemical surface scarification, by immersion in dense H2SO4 for 15 min. Two different substrate types were used, peat: perlite 1:1, v/v and filter paper moistened with water, in Petri dishes. In S. fruticosa, higher seed germination rates were observed in peat:perlite at temperatures of 10 and 15 degrees C, without seed pretreatment (33 and 23%, respectively), while the same trend was observed in Petri dishes. In S. pomifera ssp. pomifera high seed germination rates were observed in peat:perlite at temperatures of 10, 15 and 20 degrees C, without seed pretreatment (45, 38 and 43%, respectively). At 25 degrees C S. fruticosa and S. pomifera ssp. pomifera seed germination was very low (<6%) under all treatments. In the other three species very low germination rates (<13%) were generally observed under all treatments. In conclusion, lower temperatures of 10 and 15 degrees C had a favourable effect on seed germination of S. fruticosa and S. pomifera ssp. pomifera, whereas in S. officinalis, S. tomentosa and S. ringens further investigation is required. Generally, it was observed that both on peat:perlite substrates and Petri dishes, seed germination was improved for seeds that were not pretreated with chemical scarification.