Cassava periclinal chimeras: Synthesis feasibility, genotype compatibility and combining ability
Periclinal chimera are made constituted of two genotypes growing side by side. One of these genotypes makes up the epidermis, the second forms the internal tissues. As a nonconventional method to improve cassava, it brought its productivity to an extraordinary level that has never been reported before. In previous experiments the chimera were synthesized by hormone treatment, which was applied to the surface of the grafts to promote callus formation. We propose here a simple method that significantly increases the induction of periclinal chimera. It is principally to make grafts in which scions are cut in a slanted position close to a bud and the rootstock cut in the opposite direction. The scion and the rootstock are placed in close contact, having the juxtaposition of the scion and the rootstock so that the buds can make contact with each other. A cello tape is used to fasten and hold them together. We also interpret what has been noted of exceptional chimera productivity based on combining ability between genotypes of multiple ploidy levels and the movement of DNA from one periclinal chimera layer to another. Manihot fortalizensis showed the highest combining ability and the highest compatibility with all cassava cultivars tested. Before synthesizing periclinal chimera it is recommended to examine combining ability between candidate species and varieties.