OPTIMIZATION OF EXPLANT STERILIZATION PROTOCOL AND PHYTOHORMONAL COMPOSITION OF THE CULTURE MEDIUM FOR ESTABLISHMENT OF MAIZE IN VITRO CULTURE

The aim of the study was to optimize the sterilization scheme of explants using antifungal agents and to determine the effect of the phytohormonal composition of the nutrient medium on the stimulation of callus formation and shoot and root proliferation in maize in vitro. Materials and methods. At the stage of introducing maize seeds into in vitro culture, four sterilization schemes with and without fungicides were tested. The effect of cytokinin and auxin phytohormones: 6-benzyl-aminopurine (6-BAP) and indoleacetic acid (IAA) on the regeneration processes of maize in in vitro culture was determined. Results. It was found that the highest yield of sterile explants in in vitro culture was provided by treatment with “Horus” (85.8%) and “Hinozol” (95.2%). In terms of seedling viability and root length, the best results were obtained with Horus (15% and 45% higher than the control, respectively). It was established that the MS medium with 2 mg/l IAA and 0.5 mg/l 6-BAP had the best effect on explant survival (84%), callus formation processes (47%) and rhizogenesis (30%), while MS with 6-BAP 2 mg/l and IAA 0.5 mg/l was best for stimulating shoot formation. Conclusion. The optimal scheme for sterilizing maize seeds as explants for in vitro culture is: washing with soap solution (5 min), washing with running water (5 min), treatment with “Bleach” (NaOCl 10.5 g/l, 15 min), washing with sterile distillate twice, treatment with “Horus” (1.4 g/l, 15 min), washing with sterile distillate three times. It was found that the best medium for introduction into a sterile culture was MS medium: with an increased content of auxins (IAA 2 mg/l) – for inducing callus and rhizogenesis; cytokinins (6-BAP 2 mg/l) – for stimulating organogenesis.