what is the method of cassava propagation?

Answer 1

CIAT has been developing and implementing in vitro systems for cassava since the 1980s. Procedures include cleaning cassava of pathogens (especially those of viral and bacterial origin), micropropagation, conservation, and germplasm exchange.
Two propagation schemes are currently being followed, one that is low-cost and the other for mass production. The first scheme uses a participatory approach, which was first developed with a group of women farmers in the Department of Cauca, Colombia, with support from FIDAR, CBN, and PRGA. The scheme succeeded in establishing a facility for in vitro propagation in the field, replacing conventional laboratory inputs and equipment but maintaining the propagation rate (1:3).

The second scheme, involving RITA® bioreactors, increases the efficiency of solid-system propagation from 1:3 to 1:10-12. In this system, explants are periodically bathed, for short periods, in liquids containing high dosages of cytokinins.

CIAT holds in trust the most complete world collection of in vitro cassava, with about 6000 entries stored in a space of no larger than 40 m2. This active collection supports the material exchange systems of cassava germplasm certified as virus-free. Material conserved this way must be periodically subcultured to fresh mediums.

To establish complementary conservation systems for cassava, research is being conducted on systems of conservation in liquid nitrogen known as cryoconservation. Studies carried out with cassava apices made possible the establishment of a conservation system using programmers thereby achieving, for most of the tested clones, the recovery of material after freezing. Currently, encapsulation-dehydration systems are being developed to permit simple manipulations of the material during freezing. Preliminary trials with a sample from the core collection have shown the comparative advantage of this technique, compared with classic systems.

Protocols of cryoconservation have also been developed for cassava seeds and friable embryogenic callus, and some fruit trees.