Mutation induction based on in vivo and in vitro techniques as tools for cassava breeding

Mutation induction with radiation and chemical mutagens in Cassava (Manihot esculenta) is aimed at optimizing genetic variation in the frame of a Coordinated Research Program (CRP) sponsored by the Italian government in cooperation with the FAO/IAEA Joint Division and a number of African institutes mutagenic treatments were applied to in vivo and in vitro cuttings. In vivo techniques were already established and applied to a breeding program in Ghana aimed to select cassava clones with increased starch quality and mealiness. In the IEAEA Laboratories (Seibersdorf) in vitro technologies are currently investigated and applied to cassava clones. The paper reports on methodological investigations of in vitro mutagenesis with physical and chemical mutagen in nodal cuttings of cassava and the evaluation of early assessable M1V1 effects which are indicative for a mutagenic response. Most significant differences in mutagenic efficiency were obtained when the induced effect to acute and fractionate gamma doses treatments were compared. The potential of in vitro tissue culture of cassava, for mutation breeding will be also discussed.