Plant regeneration from mature Avena tissue explants

Successful plant transformation is dependent upon a reliable plant regenera tion system. In cereals, immature embryos are the explants of choice but ar e inconvenient due to their temporal nature and maintenance requirements. T he effects of three different auxins, 2,4-D, dicamba, and picloram, on two mature tissue explant types, mature embryo and hypocotyl, of three Avena ge notypes, GAF/Park, Park, and 88Ab3073, were evaluated for callus formation, somatic embryogenesis (SE), and plant regeneration capabilities. Both matu re embryo and hypocotyl explants were proliferated on modified Murashige an d Skoog (MS) basal medium containing 5, 10, and 20 mu M of each auxin and w ere regenerated on 1/2-MS medium without hormone. Although plant number was significantly correlated with SE number, it was not absolutely linked to a priori somatic embryogenesis, especially for 88AB3073 explants. While stim ulating callus growth, both dicamba and picloram decreased embryogenicity a nd regenerability over that obtained with 2,4-D. Picloram may be useful for the isolation of SE-related genes as somatic embryogenesis in oat callus w as strongly inhibited in the presence of picloram.