In Vitro Shoot Regeneration and Development of Microcorms of Moroccan Saffron (Crocus sativus L.)

Abstract

Crocus sativus L. is a male sterile vegetatively propagated plant. Its flower produces stigmas that when dried, constitute the source of a spice commonly known as Saffron. Slow vegetative propagation and diseases limit the production and the development of saffron. “In vitro” culture could be an effective method to overcome these limitations by improving the quantity and the quality of the planting materials. In this work, Crocus sativus L. segments corms of cultivar from the region of Taliouine (Southeast of Morocco) were used for the propagation through indirect organogenesis. To optimize the in vitro growth conditions, we have used the Murashige and Skoog medium (MS medium), supplemented with 2.4-dichlorophenoxyacetic acid (2.4-D) and with 6-benzylaminopurin (BAP) at combination of various concentrations. Our results showed the formation of callus in 85.42% of explants that grow in a culture medium supplemented with 2,4-D combined with BAP, at a concentration of 1mg/l each. In addition, we observed that increasing the concentration of BAP in the culture medium to 1.5mg/l improved the rate of shoots initiation (0.81). In the meantime, we noted that a combination of BAP (8mg/l) and Naphthalene acetic acid (NAA; 2mg/l) has significantly improved the rate of the formation of advanced shoots (6.65). Finally, the shoots that developed were transferred to an induction medium of roots and corms. As a result, we observed that 50% of shoots tested in ½ MS medium supplemented with 2.4-D and of BAP (1 mg/l each) and 5% sucrose, formed corms. Our study provides a first database for in vitro culture of Moroccan saffron cultivars.