Boosting saffron (Crocus sativus L.) micro-propagation through in vitro corm production

Abstract

Lack of availability of quality planting material is hampering the National program of extending saffron area in Morocco. Tissue culture has been found to be a valuable substitute to vegetative propagation due to high proliferation ratio. Corm storage at 35°C has proved to be beneficial not only in making corms more responsive to shooting but also helps in extending corm dormancy thus enabling to remove the bottle neck of available tissue culture protocols being season dependent. These states of dormancy also facilitate the corms disinfection (100%) after been soaked in pure alcohol, and then in 50% bleach solution. Culturing of saffron corms on MS media supplemented with 1.5 mg L-1 BAP + 0.5 mg L-1 NAA helps to produce 12 shoots/corm after 4 weeks. Further sub-culturing on MS + 6.5 mg L-1 BAP + 0.2 mg L-1 NAA promotes shoot multiplication, and thereafter 16 weeks on a MS medium with 3 mg L-1 BAP in combination with 80 g L-1 sucrose leads to microcorm development up to 2 g weight without any dormancy and can be used successfully for a second multiplication cycle. Direct transfer of in vitro corms on peat substratum has been found promising. The in vitro micro-propagation seems to be a very promising technology for saffron production and will help in the diffusion of any genetic progress generated by the current participatory breeding program of saffron in Morocco.