The Effects of Plant Growth Regulators, Activated Charcoal, and AgNO₃ on Microspore Derived Embryo Formation in Broccoli (Brassica oleracea L. var. italica)

Embryos derived from isolated microspore culture are of great importance for producing homozygous plants for breeding. Microspore culture can reduce time and laborious effort in the breeding of Brassica plants. Microspore derived embryos (MDE) formation in broccoli (Brassica oleracea L. var. italica Plenck) was studied with different plant growth regulators (PGRs), activated charcoal, and silver nitrate (AgNO₃) to determine the optimal chemical conditions in the microspore culture. A 6-benzylaminopurine (BA) concentration of 0.05 mgㆍL-¹ resulted in increased MDE formation compared to those at other BA concentrations. Compared to the 0.05 mgㆍL-¹ BA concentration, fewer MDEs were formed in BA concentrations exceeding 0.1 mgㆍL-¹, similar to those cultured on medium without BA. However, 0.5 × Nitsch and Nitsch (NLN) liquid medium supplemented with 0.05 mgㆍL-¹ napthalene acetic acid (NAA) and BA was more effective in inducing MDE formation than was BA alone. The higher MDE formation rate was observed in 0.5 × NLN liquid culture medium containing 0.05 mgㆍL-¹ NAA and 0.01 mgㆍL-¹ BA. The MDE yield was significantly higher in all concentrations when activated charcoal was added to the microspore culture media. The optimal concentration of activated charcoal was 1.0 mg per petri dish, and the optimum AgNO₃ concentration was 0.1 mgㆍL-¹, which induced MDE formation to 26.2 embryos, compared to 11.6 embryos without AgNO₃.