Effect of low BAP Levels on Multiple Shoots Induction in Indigenous Nigerian Pumpkin (Cucurbita pepo Linn.)

Abstract

Indigenous Nigerian pumpkin is a cucurbitaceous plant primarily grown in Southwestern Nigeria for its young leaves, which are relished as pleasant-tasting vegetable. In spite of its nutritional value, the plant is scarcely available compared to other vegetables. As a result, development of a rapid in vitro regeneration procedure is imperative to ensure all year round availability. The influence of 6-Benzylaminopurine (BAP) and 2,4-dichlorophenoxyacetic acid on multiple shoots induction from cotyledonary node explant of indigenous Nigerian pumpkin has been previously reported. However, the concentrations of BAP used may have been high, hence the inhibition of shoots formation on medium amended with plant growth regulators (PGRs). Can low concentrations of BAP alone elicit multiple shoots from cotyledonary node explant of indigenous Nigerian pumpkin? To ascertain this, we cultured cotyledonary node explants derived from 3-week-old in vitro grown seedlings for 8 weeks on Murashige and Skoog (MS) basal medium fortified with 0.35, 0.45 and 0.55 mg/L BAP. Medium without BAP (0.00 mg/L) was used as control. Mean number of shoots per explant was not statistically significant (P≤0.05) among the BAP concentrations employed except for control and medium augmented with 0.45 mg/L BAP. Medium fortified with 0.45 mg/L of BAP gave 3.25±0.921 shoots per explant and was therefore most effective for multiple shoots induction. The result showed that low levels of BAP were capable of inducing shoots formation from cotyledonary node explant of indigenous Nigerian pumpkin. Nevertheless, much lower BAP concentration than used in the present study should be investigated for the likelihood to elicit higher shoot responses.