Improvement of seed germination in winter strawberry (Rubus buergeri Miq.)

Seeds of winter strawberry (Rubus buergeri Miq.) germinate at a low rate over an extended period due to their hard coat and deep dormancy. This study compared the effects of different physicochemical treatments on the germination rate and duration of the germination period of winter strawberry seeds. Seeds were treated by sandpaper scarification, sulfuric acid (H₂SO₄) scarification, and gibberellic acid (GA₃). Of these physicochemical treatments, sandpaper scarification produced the greatest improvement to the germination rate and shortening of the germination period. Treatment with GA₃ also produced positive effects, albeit to a lesser level. By contrast, sulfuric acid scarification decreased the germination rate relative to the control group. Although GA₃ treatment had positive effects on true leaf formation and subsequent growth of seedlings, sandpaper scarification was the most effective method of inducing true leaf formation within a short period and, subsequently, for ensuring normal growth. Sandpaper scarification of seed resulted in > 90% germination, representing an approximately 80% improvement compared with the control group by week 6. Moreover, true leaves emerged in ~ 70% of seedlings within 6 weeks. Sandpaper scarification was thus a very effective seed treatment, not only for improving the germination rate and shortening the germination period of winter strawberry seeds but also for producing healthy seedlings.