Content and distribution of cyanogenic compounds in cassava roots and leaves in association with physiological age

Abstract

Background: Cassava roots are widely consumed in tropical regions of Asia, Africa, and Latin America. Although the protein,vitamin, carotenoid, and mineral content in the leaves makes them a nutritionally attractive option, their consumption is limited due to their high levels of cyanogenic compounds (CCs). In this study, the CC content in different parts of the plant (leaves, storage root cortex, and parenchyma) was assessed at harvest for 50 landrace genotypes representative of cassava diversity in Latin America. The changes in CC in leaves at different physiological ages (3, 6, 9, and 11 months after planting) were also investigated. Results: The average CC was higher in the cortex (804 ppm) and leaves (655 ppm) than in root parenchyma (305 ppm). Geno-types from different regions of Latin America, as identified by seven genetic diversity groups, differed significantly in CC levels. The Andean and Amazon groups had, respectively, the lowest (P = 0.0008) and highest (P < 0.0001) CC levels in all three partsof the plants. Cyanogenic compound concentrations were higher in leaves from young plants (P < 0.0001) and decreased with increasing physiological age. Conclusion: The results help to guide the selection of parental lines with low CC levels for breeding and to contribute to the expanded use of cassava and its by-products for food and feed. Cassava for fresh consumption, especially, requires varieties with low total CC content, especially in the root cortex and parenchyma. COL1108 (204, 213, and 174 ppm, respectively, in the parenchyma, cortex, and leaves) and PER297 (83, 238, and 299 ppm, respectively, in the parenchyma, cortex, and leaves)can fulfill this requirement