Influence of explant collection period, antibrowning strategy and growth regulators composition on in vitro propagation of Bhagwa pomegranate

In vitro propagation is a rapid mean for production of disease-free and healthy plants. Using nodal segments for in vitro propagation of pomegranate cv. Bhagwa, the effect of time of explant collection and anti-browning strategy on culture establishment were investigated. A combination of growth regulators (BAP, NAA) and growth substances (AgNO₃, Adenine sulphate) were also tested for shoot bud initiation, shoot proliferation and in vitro rooting. In a culture cycle of April to July months, the maximum explant establishment (58.07%) was recorded in the month of April. The medium supplemented with activated charcoal (2.5 g l⁻¹) induced significantly higher culture establishment (63.9%) than control and the treatments involving pre-culture shaking of explants with polyvinylpyrrolidone (PVP) (1.0%) solution or antioxidants (100 mg l⁻¹ citric acid + 150 mg l⁻¹ ascorbic acid) solution. For shoot bud initiation from nodal segments, different levels of BAP (0.5, 1.0, 1.5 and 2.0 mg l⁻¹) alone or with NAA (0.25 mg l⁻¹) were tested. The significantly highest response (85.17%) was achieved on MS medium supplemented with BAP (1.0 mg l⁻¹) + NAA (0.25 mg l⁻¹). The AgNO₃ (1.5 mg l⁻¹) enabled maximum survival of cultured shoots during sub-culture stage. The MS medium containing BAP (0.5 mg l⁻¹) + NAA (0.5 mg l⁻¹) + AgNO₃ (1.5 mg l⁻¹) + Adenine sulphate (40 mg l⁻¹) was good for shoot multiplication. The half strength MS medium supplemented with NAA (1.0 mg l⁻¹), was suitable for rooting of shoots in vitro.