Micropropagation of Jojoba (Simmondsia Chinensis) an oil Yielding Plant of High Commercial Value

Abstract

The present work deals with micropopagation potential of jojoba (Simmondsia chinensis) an oil yielding plant of high commercial value. To explore the callogenic and organogenic potential of different explants, five explants (leaf, cotyledon, stem, shoot apices and nodal segments) were used in two media MS and B5 (containing different concentration of NAA, IAA, GA3, 2, 4-D, BAP, Kin and 2ip). Callus was initiated in all explants at all supplementation of auxins and cytokinin. Callus induction and its proliferation varied depending upon the explant type, its size and hormonal combination. However, 0.5 cm long nodal explant proved best for callogenesis. The combination MS+5mg/1 IAA and 10mg/1 BAP proved the best because it formed 100% callus after 14 days. The callus obtained from nodal explant also proved best for regeneration. Shoots were obtained after 30 days of inoculation on the medium used for callogenesis. For rooting, out of different combinations MS+10mg/1 IBA and 1mg/1 IAA proved best as 90% rooting was achieved in this combination in 25 days. For in vitro micropropagation two explains i.e. shoots apex and nodal segments of variable sizes were used on two media, MS and SH supplemented with various concentrations of IAA and BAP. Of the two explants of variable size used, 2.5 cm long nodal segment were found more efficient in shooting and its proliferation. Out of two media, MS and B5, MS+5mg/1 IAA + 10mg/1 BAP proved best as it gave 100 % regeneration in 10 days. Micropropagated shoots from nodal segments failed to ro0ot when transferred to MS medium probably due to release of phenols which retards rooting. Special stem wound technique was adopted with these shoots prior to placing them on MS medium containing different concentration of sucrose and IBA. The shoots having vertical incision just above their cut ends and dipped in 0.8% PvP and 20.3mg/1 IBA proved best I rooting response when later placed on 1/2 MS+2.03 mg/1 IBA and 1.5% sucrose. Nodal segments were also explored for embryogenic potential. Out of different concentration MS containing 1.5mg/1 NAA + 2.0mg/1 2ip, induced embryogenesis. Terminal nodes proved best for callusing than subterminal one. After 4 weeks of initiation callus contained numerous globular shaped pre-embroids, which after 6 weeks of initiation changed to heart shaped and after 8-10 weeks into torpedo shaped embryoids. Cultures shooting, rooting and embryogenesis were maintained under three light systems with varying photoperiod ad intensity. Photosystem-I proved best for its suitability for shooting, rooting and embryogenesis. In vitro regenerated plantlets (callogenic and micropropagated) were successfully transferred to clay pots filled with autoclaved sand and compost (1:1). Under high moisture condition, these plantlets grew well and after two week of hardening plantlets were shifted to large pot. They acclimatized well to low moisture environmental stress. The present results are quite significant as growth conditions, culture media, hardening and acclimatization protocols have been optimized. This is step towards for commercial production of male and plants are desired.