Abstract

Background: Okra (Abelmoschus esculentus) is belongs to the family Malvaceae and genus Hibiscus. Conventional propagation of okra in a large scale is limited due to bacterial, fungal, viral disease and seed dormancy. Hence, micropropagation offers great potential to increasing the commercial availability of okra. This study aimed to investigate the effect of MS strength, sucrose concentration, and pH on the in vitro propagation of A. esculentus from shoot tips.

Results: Okra seeds were sterilized with 70% alcohol, 30% (v/v) Berekina and 0.13% HgCl2 (w/v) for 5, 40 and 10 minutes respectively. The shoots were excised from in vitro germinated seedlings and transferred to full strength MS liquid medium containing 1mg/L BAP. The in vitro initiated shoot tips were transferred to different MS strength (1, ½, ⅓, ¼) medium, sucrose concentration (30 g/L, 20 g/L, 15 g/L, 10 g/L) and pH level (pH 6.6, 6.2, 5.8, 5.4, 5.0) that contained 1.5 mg/L BAP and 200 mg/L activated charcoal. For rooting, different MS strength (full, ½, ⅓, ¼), sucrose (30 g/L, 20 g/L, 15 g/L and 10 g/L) and pH (6.6, 6.2, 5.8, 5.4, 5.0) that contained 1mg/L IBA with 200 mg/L activated charcoal were used. Full strength MS medium containing 30 g/L sucrose at pH 5.8 produced the highest mean shoot number (7.93), mean leaf number (14.37) and mean length (6.4 cm) per explant. Similarly, at pH 6.2 and 6.6 maximum shoot mean number (6.53, 5.80), leaf number (12.77, 10.43) and shoot length (6.32, 5.82 cm) were produced respectively. Maximum mean root number (15.73) and root length (6.05 cm) were recorded at ½ MS strength. At pH 5.8, 6.2 and 6.6 maximum mean root number (1.77, 1.47, 1.80) and root length (1.38, 1.25, 1.39 cm) were obtained. After acclimatization, 86% of plants survived in greenhouse.

Conclusion: Decreasing the MS strength, sucrose concentration and pH level had an inhibiting effect on both shoot multiplication and root formation of okra. Besides increasing pH value showed inhibiting effect on shoot multiplication.

Keywords: Abelmoschus esculentus; Micropropagation; MS medium; pH; Salt strength