Breeding for acquired disease resistance in open pollinated yam genotypes through cytoplasm defense mechanism - a review

Resistant varieties developed through plant breeding have made much contribution to Agriculture. This is because stability in crop production depends more on resistant varieties. Based on this, detailed review on the cytoplasm resistance and cytoplasm defense was carried out to enable Plant breeders develop yam genotypes with acquired disease resistance. Therefore yam plants that failed to inherit resistance genes could be made to acquire cytolasmic resistance mechanisms through field evaluation in hotspot agro ecologies. In cytoplasmic resistance, the plant plasmids acquired foreign genes to make such yam plant resistant to pathogens. Even if the pathogen has penetrated the preformed defense structures, the yam plants could respond by forming defense structures which involve the cytoplasm of the yam plant cells under attack to destroy the pathogen, a process known as cytoplasmic defense reaction. Protoplasm of related and unrelated yam plants could also be fused causing the regenerated yam plants to acquire resistance to major diseases. With these cytoplasmic defense mechanisms, yam plants could effectively thrive in pathogen prone environments. Developed disease resistant yam plants are not expensive to maintain and are environmentally friendly.