Micropropagation for recovery of Cucumis hystrix

A micropropagation protocol that allows for the efficient cloning of C. hys trix was developed using 1 mm shoot-tip explants prepared from plants grown in the greenhouse. Establishment of Stage I cultures was greatest (83%) wh en shoot tips were cultured in modified MS (Murashige and Skoog, 1962) medi um containing (per liter) 30 g sucrose, 0.1 g myo-inositol, and 5 g Agargel plus 1.7 muM indole-3-butyric acid (IBA), 0.5 muM kinetin and 0.3 muM gibb erillic acid (GA(3)) (IKG). Benzyladenine (BA, 5 muM) proved best for Stage II shoot proliferation. Over 35 shoots were obtained per vessel (five shou ts per vessel) when explants were cultured in medium containing BA. Less th an 10 shoots were obtained per vessel when kinetin (0.5-5 muM) and IKG were used. Stage II cultures established from 1 cm shoot tips obtained from Sta ge I shoots produced more shoots (1.3-fold) than single node explants. Root ing and plantlet acclimatization were best when shoots greater than 1.5 cm were incubated in MS medium containing 0.5 muM naphthalene acetic acid (NAA ). Higher NAA concentrations stimulated rooting but inhibited shoot elongat ion and reduced the ability of plantlets to survive acclimatization to ambi ent conditions. Plantlet height influenced acclimatization. Over 72% of pla ntlets survived acclimatization if they were at least 4.6 cm when transferr ed to soilless growing medium.