Ultraviolet radiation (UVR) is a powerful ionizing mutagen capable of altering plant cell chromosomes and enhancing genetic diversity. The category of UVR used, was Ultraviolet C (UV-C) with a wavelength of 100-280 nanometers (nm). This study assessed effects of UV-C treatments on Corchorus olitorius (C. olitorius) seed germination, speed of germination, seedling vigor and mitotic cell division; of Amugbadu and Oniyaya accessions. Sourced from National Horticulture Research Institute (NIHORT) Ibadan, Nigeria. Five experiments (4 Laboratory and 1 field) were conducted at Babcock University Ilishan, Ogun state, Nigeria, consisting of five treatments. Four were exposed to UV-C radiation for 1-4 hours at 254 nm, with intensity of 54mJcm-2 and Wet Heat Treatment, which is the control. Each treatments were replicated three times, data collected on above measured parameters, analyzed using Analysis of variance, Duncan Multiple Range Test at (1% and 5% levels of probability) and Pearson correlation coefficient. Results showed highly significant treatments effects on germination count/percentage, germination index, and seedling vigor at 1% probability level. A generally low/decline of UV-C treatments effects were observed, except for 3-hours exposure. Evident in treatments impact mean germination percentage ranging from 18.67 (1hr) to 77.33 (control). UV-C treatments led to prolonged cellular in-activities at interphase and inhibitory changes at some mitotic phases, indicating cellular stress. Despite these low and inhibitory effects, all treatments induced C. olitorius seed germination and break its dormancy; offering insights into crop response or resilience to UV stress and potential for genetic improvement.

Keywords: Mitotic index, seed germination, seedling vigor, roots cells microscopic views.