A series of rice somaclonal variants with photooxidation tolerance have been screened and preliminarily identified. It is indicated that somaclonal variants (regenerating plants) from calli of mature caryopsis of 02428 and Chugoku 91 which are tolerable to photooxidation are also tolerant and that those from 842, Meixuan Minghui 63-38, Meixuan Minghui 63-53, and Guichao 2 which are sensitive to photooxidation display a wide spectrum from sensitivity to tolerance under photooxidative condition, among them (168 variants) from 4 sensitive parents 2 variants (numbered as 93012, 93236) have strong ability and 17 variants have medium ability against photooxidation. Decline of net photosynthetic rates of these tolerant variants is remarkably less than that of sensitive variants under photooxidative condition. Moreover it is initially proved in posterities of some variants that this type of variation is of genetic stability. We suggest that rice somaclonal variants with photooxidation tolerance provide a new source of variation which could be used in breeding rice cultivars with higher photosynthetic efficiency in the near future.
