Cyanogens and Linamarase Activities in Storage Roots of Cassava Plants from Breeding Program

Storage roots of cassava clones arising from six crosses between cassava varieties of different cyanogen levels were analyzed for total cyanogen content and linamarase (β -glucosidase) activity. Total cyanogen content for 113 clones ranged from 120 to 1941 mg HCN equivalent/kg roots dry wt., the mean±S.D. being 666±387 mg HCN equivalent/kg roots dry wt. Among these, eight clones exhibited low cyanogen content (mean value <200 mg HCN equivalent/kg roots dry wt.) as compared to 19 clones which yielded cyanogen contents greater than 1000 mg HCN equivalent/kg root dry wt. Two clones had cyanogen levels lower than the parental variety with low cyanogen content. Depending on the cassava clones, the β -glucosidase activity of storage roots varied from 1.1 to 5.5 nkat/g root fresh weight and was not correlated with the total cyanogens of the storage roots (r=0.17). Some clones with even lower cyanogen content and higher linamarase activity than their parental variety were observed and these might contribute to safety in cassava consumption. Overall, data on total cyanogen content and linamarase activity in cassava roots have relevance to what processes should be developed for processing cassava roots for consumption.