Shoot regeneration frequency from cotyledon explants in Micro-Tom (MT) and MT- Rg1. A. MT and MT-Rg1 explants (8 days old) were tested in MS medium supplemented with 5 μM 6-benzylaminopurine (BAP) or 5 μM Zeatin. B. MT and MT-Rg1 explants with different ages (days after sowing) were tested in MS medium supplemented with 5 μM BAP. C. MT explants (8 days old) were tested in MS medium supplemented with 5 μM BAP or 5 μM Zeatin with or without 2 days pre-incubation in MS medium supplemented with 0.4 μM 1-naphthaleneacetic acid (NAA). In all treatments, the regeneration frequency (percentage of explants with well formed adventitious shoots) was observed 21 days after explants inoculation. Vertical bars indicate ± standard deviation of the mean (n = 6 Petri dishes with 20 explants each). Different letters indicate significant differences at P ≤ 0.05 (Student's t-test).