Breaking seed dormancy in a forest plant: Grewia damine Gaertn

Seeds of Grewia damine are dormant and vegetative propagation is difficult which act as an obstacle for the introduction of this species for commercial or conservation processes. Therefore, the present study was conducted to identify the seed dormancy breaking treatments to improve seed germination of G. damine. The following dormancy breaking treatments were applied: control (intact seeds); scarified seeds with sand paper; hot water treatment (100⁰C) for 5, 10 and 15 minutes; refrigeration at 2-5⁰C for 1, 2 and 3 weeks; Conc. H₂SO₄ or HNO₃ immersion for 5, 10 and 15 minutes. Germination parameters were measured and the data were subjected to ANOVA in Minitab 15. A significantly high (p < 0.05) germination percentage (93%) and other germination parameters (GS= 13.628, GMT= 4.956, GI= 5.556 and T_50%= 5.447) were recorded in the treatment of scarification with a sand paper followed by the treatments with Conc. H₂SO₄ for 15 minutes and boiling water for 5 minutes where germination was 55 %. While significantly low germination of 22 % was recorded with Conc. HNO₃ for 15 minutes. The results suggests that seeds of G. damine possess a physical dormancy. None of the untreated seeds of G. damine germinated within the study period and scarification with a sand paper proved to be the most effective method of breaking seed dormancy. Hence seeds could be used by the nurserymen after breaking dormancy to produce plant material at large scale.