Varied responses to copper for plant regeneration from calli of different rice varieties

Enrichment of copper to the culture mediumcould enhance the plant regeneration from cal-lus of indica rice variety Qiugui＇ai 11.Westudied the effect of copper on plant regenera-tion of other rice varieties. Calli of 14 indica and 2 japonica varietieswere induced from disinfected mature embryoson an agar-gelled medium containing N_6 basalelements and 2 mg/L 2,4-D.Compact andnodular calli were selected and proliferated onthe same fresh medium.After 1 or 2 passages