A Novel Approach for the Determination of an Optimal Medium for Improving Rapid Micropropagation of Cucurbit Citrullus mucosospermus Fursa

Abstract

The search for a suitable medium for In vitro regeneration, whatever the species cultured, is always done by tests including successive steps of removal of components of the culture medium that do not give the expected results. This is the usual procedure. However, the effects of interactions are not taken into account. It is therefore with the aim of taking into account the interactions between the constituents of the culture medium in the formulation of the medium that motivated the present study. Therefore, in order to find the optimal composition with a minimum of experiments or trials, experimental planning was a particularly useful tool. The results of the experiments are analyzed and recommended response values are calculated. A Box-Behnken design wasused by varying three factors: MS mineral elements, sucrose and 6-benzylaminopurine (BAP). Agar concentration has been kept constant. Shoot induction depended on the interaction between levels of sucrose, BAP and MS mineral elements in the medium. The optimum formulation for numerous shoots production is medium containing 1.5 strength of MS mineral elements, 35 g/l sucrose and 1 mg/l BAP solidified with 6 g/l agar. After 3 weeks of culture, 76.7% of the cotyledon explants (proximal parts) regenerated shoots with an average of 12 shoots per explant and a mean shoot length of 17 mm. Compared with the usual procedure, this procedure showed an increment of shoots number per explant and shoot length. The shoots regenerated were directly rooted. Overall, these results make a relevant contribution to the optimization of In vitro propagation of Citrullus mucosospermus Fursa oleaginous type and other hard to propagate related species.