Callus induction and regeneration efficiency of spring barley cultivars registered in the Czech Republic

Immature zygotic embryos are frequently used for induction of cell cultures in vitro and for genetic transformation. The effect of three synthetic auxins: 2,4-dichlorophenoxyacetic acid (2,4-D), 3,6-dichloro-2-methoxybenzoic acid (dicamba) and 4-amino-3,5,6-trichloropicolinic acid (picloram) on induction and subsequent regeneration capacity of barley. In vitro culture was studied in 12 spring barley cultivars registered in the Czech Republic and a variety of Golden Promise, with known high regeneration efficiency. The callus formation frequency and number of green regenerants were influenced significantly both by genotype and auxin. Most cultivars formed statistically significantly a higher mean number of regenerants (1.95) after the callus induction on the medium with 2.4-D as compared to the media with picloram and dicamba. Only two cultivars (Nordus and SG-S-261) did not respond to the used auxins differently. The highest average number of regenerants (from all three auxins) was obtained with Golden Promise (2.7 plants per one cultivated scutellum). From the set of genotypes used in our study, the cultivars Atribut, Forum, and Scarlett with the mean number of regenerants (2.09-1.57) would be the most suitable cultivars for further transformation use. They differ statistically significantly from the cultivars Nordus, Amulet, Akcent, SG-S-252, Orbit, and Granát (0.42-0.92) which had the lowest mean number of regenerants.