Progress on cassava improvement through biotechnology at the National Root Crops Research Institute, Umudike

A plant tissue culture laboratory was set up at the National Root Crops Research Institute, Umudike in 1990 through the support of the International Atomic Energy Agency Vienna. The primary objectives are to improve root and tuber crops through mutation breeding and in vitro culture techniques. Rapid micropropagation is routinely carried out for cassava, to multiply irradiated plantlets through the various vegetative cycles (M1V0-M1V3) leading subsequently to the selection of desirable mutants. Plantlets of two cassava cultivars (TMS 30572 and U/41044 raised) in vitro were irradiated using 20 and 25 Gy after a radiation sensitivity test. Up to five thousand M1V3 plantlets at the first instance, will be hardened, transplanted to the field and screened for early maturing types, reduced cyanide levels, resistance to pests (green spider mites and mealy bug) as well as the African Mosaic Virus. Some observable characters in the M1V2 population in vitro include very vigorous growth and stunting with pronounced tuberlet formation. Up to 58.96 percent loss was sustained in the Institute's cassava germplasm collections between 1980-1990 due to pests, diseases and adverse weather conditions. Consequently, duplication of collections in vitro for safer preservation is in progress.