Plant regeneration from callus of intergeneric hybrid Agropyron repens (L.) Beauv.
x Bromus inermis Leyss cv. nanus (AGROMUS) was carried out on a new culture medium
designated medium-F. Within 21 days of the plating of inflorescence primordia the
initiated callus showed globular structures. From the 21st. day of culture, one step
plant regeneration occurred on the callus without subculture. The new basal medium
reported in this work was effective in callus initiation and plant regeneration of
the hybrid AGROMUS by (i) the reduction of the total ion strength (2.6 g/l, 22.5 mM)
of macroelements compared to MS (4.5 g/l, 45.2 mM), (ii) the use of NH4NO3 as the
sole N-source, and (iii) the application of KH2PO4 at an 8 times higher concentration
(1160 mg/l, 8.5 mM) when compared to the Murashige and Skoog medium composition. This
medium provided a 2 to 10 fold reduction in the 2,4-dichlorophenoxyacetic acid supplement
needed for the callus initiation and one step plant regeneration after a gibberellic
acid (2 mg/l, for 5 days) pretreatment of tillers. The regenerated plantlets were
subcultured in multi-shoot culture and potted in soil to grow for further analysis.