Morphogenic Potential of Different Explants of Broccoli (Brassica oleracea L. var. italica): Important “Nutrient-Rich” Vegetable, Using Thidiazuron

Abstract

Broccoli is a high-valued nutritionally rich important cole vegetable crop. But its quality and quantity are largely affected by various pests, diseases, and environmental stresses. Traditional plant breeding technologies alone are not sufficient to control its massive losses because of no natural genetic variations present in its germplasm. Genetic manipulation can supplement the conventional agricultural practices for broccoli improvement. The objective of the present study was to evaluate the effectiveness of thidiazuron (TDZ) in in vitro high-frequency plant regeneration studies in broccoli using hypocotyl, cotyledon, petiole, and leaf explants. Highly efficient and reproducible regeneration protocol has been optimized in broccoli cv. Solan green head. Explants were cultured on Murashige-Skoog (MS) medium, containing different TDZ concentrations and combinations such as TDZ alone, TDZ + adenine, TDZ + NAA (naphthalene acetic acid), and TDZ + IAA (indole acetic acid). Total 36 combinations were used; the maximum shoot regeneration response was observed in hypocotyl explants (95.92%) on MS medium supplemented with 2.0 μM TDZ + 0.5 μM IAA followed by petiole explants (91.55%) on MS medium with 2.0 μM TDZ + 0.107 μM NAA. Leaf explants gave (89.25%) shoot regeneration response on MS medium containing 1.0 μM TDZ + 0.107 μM NAA and cotyledon explants producing multiple shoots (88.88%) on MS medium supplemented with 2.0 μM TDZ + 0.59 mM adenine. After completed shoot regeneration, high-frequency (100%) root regeneration response was observed on rooting medium containing 0.10 mg/l NAA. For hardening, in vitro regenerated plantlets were transferred to pots containing cocopeat and successfully acclimatized. Well developed in vitro plant regeneration protocol has been optimized in broccoli cv. Solan green head using potent cytokinin thidiazuron.