Methods for overcoming seed dormancy of Schizolobium parahyba var. Amazonicum

Abstract Schizolobium parahyba var. amazonicum is a tree species of great commercial interest, however, its seeds present tegumentary dormancy. Thus, the objective of this work was to evaluate the efficiency of different scarification methods to suppress seeds dormancy of S. parahyba. The treatments consisted in the following scarification methods: Grain 400 mechanical sandpaper (Sandpaper); Water at 100°C for 1 minute (Water-1m); Water at 100°C for 2 minutes (Water-2m); 70% NaOH for 12 hours (NaOH-12h) and 70% NaOH for 24 hours (NaOH-24h). Germination and growth were assessed during a time of 40 and 60 days, respectively, in order to obtain the variables of germination percentage, survival, mean emergence time (MET), speed emergence index (SEI), and growth in height. The treatments Sandpaper, Water-1m, and Water-2 presented the highest seedlings emergency (99%, 98%, and 97%, respectively) and the highest survival means (98%, 96%, and 92%, respectively). The treatment with electric sandpaper showed to be a good alternative whether compared with the scarification with manual sandpaper. The thermal treatments with hot water at 100°C during 1 minute and 2 minutes also showed to be a good alternative in relation to the conventional dormancy suppression of S. parahyba seeds due to its greater practicality and shorter initial seed preparation time.