Four interspecific hybrids between cassava (Manihot esculenta Crantz) and wild Manihot species were polyploidized by colchicines application to buds of cuttings. Totally tetraploid types as well as sectorial and periclinal chimeras were produced. Somatic selection applied to lateral buds of sectorial chimeras induced totally tetraploids. Fertility was restored in the sterile interspecific hybrids by chromosome dupling up to 93% viable pollen production in the tetraploids compared to 13% in diploids, which could lead to the evolution of new Manihot species. Periclinal chimeras showed high vigour compared to both tetraploid and diploid plants.
Cassava, polyploidy, chimera, pollen viability, hybrid fertility, interspecific hybrids
