Regeneration of M1 plants from 'de-embryonated' cotyledons to modify diplontic selection

Peanut (Arachis hypogaea L.) cotyledons, after excision of the embryonal axis, were cultured in enamel trays lined with moist cotton wool. The cotyledons turned green and produced callus, roots or adventitious shoots in the basal region from where the embryonal axis was removed. Application of benzyladenine enhanced the frequency of adventitious shoot formation. When transferred to the field, the cotyledons developed into nearly normal-looking plants which produced pods and seeds. Such cotyledonary plants raised from unirradiated control and seeds exposed to 20 kR of gamma rays were progeny tested in the M2 generation. No mutations were found in 153 cotyledonary plant progenies of control. Sixteen per cent (13 out of 80) of the cotyledonary plant progenies raised from seeds exposed to gamma rays segregated for mutation. This was lower than the number of seed-raised progenies that segregated for mutation. (author)