Evaluation of cassava (Manihot esculenta Crantz) genotypes for total cyanide content, storage tuber and starch yield in South Western Ethiopia

Abstract

Cassava (Manihot esculenta) is one of the main food crops that significantly contribute to food security and poverty alleviation in South and Southwest Ethiopia. Cyanide present in cassava roots poses a health challenge in the use of cassava for food. It is therefore important to identify the sweet and bitter types for food and industry. In this study, 11 farmers preferred genotypes were assessed for storage tuber yield, cyanide content and starch contents at Jimma, Metu and Tepi during 2015-2017 cropping seasons. From the genotypes analyzed, AAGT-108 (128.35 mg/kg) and AAGT-189 (118.5 mg/kg) are identified for bitter type (high HCN content). Based on storage tuber yield, genotype AAGT-108, AAGT-189 and AAGT 192 produced the highest tuber yield in all tested locations. The starch content varies from 5.11 (Qulle at Metu) to 18.40 (AAGT-108 at Tepi). Similarly, genotypes AAGT-108, AAGT-189 and AAGT-192 are the best materials at Jimma as compared to others and gave the mean starch content of 15.22, 16.98 and 16.61 %, respectively. Based on the overall result of hydrogen cyanide and starch contents, genotype AAGT-108 and AAGT-189 are recommended for bitter type (high HCN content). On contrary, the rest of genotypes have sweet type due to low hydrogen cyanide content below 100 mg/kg and are recommended for human consumption.