Thermal shock to overcome the dormancy of diaspores Tectona grandis L. f.

Abstract

The objective of this study was to testpre-germinationtreatments to overcome Tectona grandis L. f. diaspores dormancy.  The experiment was conducted at the UFT Laboratory of Seed and seedling nursery - Campus of Gurupi. Six parent trees were utilized as seed providers, all of them located in the agroforestry system. The treatments were: (T1) intact seeds; (T2) seed heating in an oven at 80 °C for 12 h without immersion in water; (T3) seed heating in an oven at 80 °C for 12 h, followed by immersion in water for 6 h; (T4) seed heating in an oven at 80 °C for 12 h, followed by immersion in water for 8 hours; (S5) seed heating in an oven at 80 °C for 12 h, followed by immersion in water for 10 h; (T6) seed soaking  for 16 h at night and warming in the sun for 8 hours during the day, followed by immersion in the end for 24 h; (T7) seed soaking for 16 h at night and warming in the sun for 8 hours, for three days, and at the end, soaking for 24 hours. Seedling emergence, emergency speed index, length and mass were biomass. The mean results were submitted to analysis of variance and compared by Tukey at 5% probability.We conclude that treatment (T2) provided the best results percentage and emergency speed index, but still gave low values, requiring further studies with this species.