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

Abstract

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