Toona Sureni (Blume) Merr. Seeds Invigoration Using Co-60 Gamma-Rays Irradiation

Deteriorated seeds can be improved by invigoration treatment, including gamma-ray irradiation by Cobalt-60 (Co-60). The purpose of this study was to determine the proper dose of gamma-ray irradiation (Co-60) to increase the decreased vigor of suren (Toona sureni (Blume) Merr.) seeds. This study uses a factorial completely randomized design (CRD) with aging and irradiation as the treatments. Aging factors consisted of 0, 2, and 4 days. Irradiation factor consisted of 7 levels, namely 0, 5, 10, 20, 40, 80, and 100 Gy, repeated four times. The parameters observed were the electrical conductivity, germination percentage, germination speed, and seedling height. The results showed that Seed aging treatment significantly affected Suren seed germination with 75% (2 days aging) and 56% (4 days aging) germination. The 40 Gy dose of gamma-ray irradiation could increase germination percentage and germination speed of low suren seed vigor increasing 51.42% and 60.21%, respectively. Simultaneously, the cell membrane damage of stored suren increased with gamma-ray irradiation treatment of more than 40 Gy based on electrical conductivity. In seeds with high germination, such as seeds without aging and seed aging for two days with a germination percentage of 80% and 75%, respectively, the invigoration treatment was not effective. Invigoration treatment was effective in increasing the deteriorated or low viability and vigor of the suren seeds.