Callus Initiation and Plant Regeneration from Triticale Embryos1

Abstract

This study was conduced to determine optimal concentrations of sucrose and combinations of growth regulators required for callus initiation and plant regeneration from immature embryos of 'Councill' and other triticales (X Triticosecale Wittmack) and to make histological observations of triticale callus during differentiation and organogenesis. Immature triticale embryos were cultured on a basal medium containing the salts of Murashige and Skoog and vitamins plus selected concentrations of sucrose and different auxins or cytokinins, alone or in combination. The optimal concentration of sucrose for increasing fresh weight of callus derived from hexaploid embryos was 20 g/liter. The addition of 2, 4‐D [(2, 4 dichlorophenoxy) acetic acid] to the basal medium was superior to the addition of IAA (indoleacetic acid), kinetin (6‐furfurylaminopurine) and auxin/cytokinin combinations for both callus initiation and growth. higher concentrations of 2, 4‐D (6 mg/liter) promoted callus initiation and growth, but prevented plant regeneration on callus subsequently subcultured to a medium without growth regulators. Histological observations gave evidence of formation of active growth centers or meristemoids in callus. These subsequently led to differentiated root primordia. Our study showed that triticale embryos behaved similar to other cereals in their callus initiation and plant regeneration traits.