[en] Dry seeds of rice were implanted with 15∼ 30 keV nitrogen ion beam of various doses. The biological effects in M₁ and mutation in M₂ were studied. The results showed that the nitrogen ion could induce the variation on the chromosome structure of rice. The chromosomal aberration rate of cells tended to be increased with increase of implanted ion dose. However, the aberration rate was low than that induced with ⁶⁰Co γ-rays. Peroxidase isozymograms in rice seedling were changed after ion beam implanting. Frequency of the chlorophyll mutation implanted by nitrogen ion beam was higher than that induced by γ-rays. Mutation frequencies of heading date and plant height were similar between ion beam implanting and γ-rays irradiation