Rooting and acclimatization of cassava (Manihot esculenta) ex vitro

Micropropagation of cassava is relatively straightforward and shoots from microcuttings can root without plant growth regulators in vitro. However, acclimatizing in vitro rooted shoots can result in high mortality. Cassava roots are prone to deterioration following wounding or bruising causing great losses during acclimatization. Direct rooting was conducted of cassava shoots pretreated by growing them in vitro on 0% to 10% sucrose. Shoots, 1.5 cm in length from the varying sucrose media were rooted in vitro in medium grade vermiculite or in situ in ProMix (TM) potting medium. Sucrose levels > 6% caused shorter plants than the other treatments. Shoots rooted equally well with both media. A success rate of > 95% was obtained following rooting in vermiculite followed by transfer and acclimatization in a ProMix (TM) potting medium. Vermiculite was easily removed from cassava roots reducing the damage normally occurring during the rinsing and removal of adhering gelled medium. In vitro rooting of cassava in vermiculite increases survival rates during acclimatization. Direct rooting in pots was most successful from shoots grown on 4% to 8% sucrose.