Embryogenic callus induction and plant regeneration in Triticum tauschii, the diploid D-genome donor for bread wheat (Triticum aestivum)

Immature embryos of seven accessions of Triticum tauschii (Coss.) Schmal. were used to produce embryogenic callus suitable for initiation of suspension cultures. Several modifications of Murashige and Skoog basal medium (MS) were evaluated for callus induction from scutellar tissues of embryos. Nodular, embryogenic calli were induced from all accessions when MS medium was supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) and a mixture of L-glutamine, L-asparagine and L-proline. Early differentiation of these embryogenic calli was overcome by substituting Dicamba for 2,4-D. Addition of 575 mg L(-1) of L-proline gave a rapid increase in the production of nodular embryogenic callus in most of the accessions. Using this protocol, the embryogenic capacity of this type of callus was maintained for more than a year following further modification of the MS medium. A clear genotype dependency as well as media effects on the production of callus were observed.