Silver nitrate (AgNO3) boosted high-frequency multiple shoot regeneration from cotyledonary node explants of okra (abelmoschus esculentus L.)

Abstract

Okra (Abelmoschus esculentus L.) regeneration frequency to a large extent depends on its genetic structure and its recalcitricity. In present study, the influence of silver nitrate (AgNO3) in combination with cytokinins such as 6-benzyl amino purine (BAP) and kinetin (KIN) to regenerate multiple shoots from cotyledonary node explants of A. esculentus were optimized. Cotyledonary node explants were excited from 10-days old okra in vitro seedlings and incubated on Murishage and Skoog (MS) medium supplemented with different concentration and the combination of BAP alone and in combination with KIN. The highest percentage of shoot bud regeneration (75%) was achieved on MS medium supplemented with 2.0 mgL-1 BAP. Highest percentage of shoot multiplication and proliferation (85%) with 6.75 shoots per explant having 3.75 cm length was obtained on MS medium containing 1.5 mgL-1 BAP + 1.5 mgL-1 KIN + 3.0 mgL-1 AgNO3. On the other hand, non-containing AgNO3, the combination of 1.5 mgL-1 BAP + 1.5 mgL-1 KIN, a maximum of 53% shoot multiplication with 2.3 shoots per explant having 3.75 cm length was recorded. Individual shoots were elongated on MS medium supplemented with 1.5 mgL-1 BAP + 1.5 mgL-1 GA3 (Gibberellic acid) (shoot length 5.60 ± 0.70a cm) and rooted on half strength MS medium + 1.0 mgL-1 IBA (Indole 3-butiric acid) + 200 mgL-1 AC (Activated charcoal), with highest root formation 83% with 5.20 roots per shoot having 4.8 cm length was achieved. The current protocol will be useful for the development of okra transgenic plant as a result of genetic transformation.