Diversity in oil content and fatty acid profile in seeds of wild cassava germplasm

- We analyzed oil content and fatty acid profile in seed of wild Manihot species.
- The oil and fatty acid contents varied between species and accessions within a species.
- Linoleic acid was the most prevalent acid in seeds of the wild cassava species analyzed.
- Seeds of some wild cassava were larger than of cultivated cassava.
- The content of oil is comparable to the oil content in seeds of species already used as oil crops.

Cassava (Manihot esculenta) is the only commercial species of the Manihot genus, cultivated for its starchy tuber roots. However, cassava seeds are known to be rich in oils and fats, there are scant reports on the content and properties of oil from cassava seeds and its wild relatives. Wild Manihot species usually produce a higher number of seeds with a large diversity in shape and weight. Seeds of 106 accessions belonging to 12 species of Manihot from the collection of Embrapa Cassava and Fruits were evaluated for oil content by NMR and fatty acids composition by gas chromatography. The oil content ranged from 17.2% (M. caerulescens) to 30.7% (M. flabellifolia) and the species clustered into eight different groups based on the oil content. Five fatty acids were found in all species with the average content of the fatty acids being: linoleic (C18:2) 61.5%; oleic (C18:1) 20.0%; palmitic (C16:0) 12.3%; stearic (C18:0) 4.5%; and linolenic (C18:3) 1.7%. The content of fatty acids varied significantly between species as well as between accessions within a species. The highest content of linoleic acid was in seeds of M. peruviana, M. pseudoglaziovii, M. cecropiaefolia, M. flabellifolia, M. glaziovii and M. carthaginensis (average of 65%); and the highest level of oleic acid was in M. caerulescens, M. esculenta, M. anomala, M. dichotoma and M. tomentosa (average of 23%). The collection of Embrapa's Manihot germplasm is a valuable source for cassava breeding programs, containing a large variability in seed size, oil content and fatty acid composition. The oil from seeds of wild Manihot species may be equally valuable for industrial uses as oil from seeds of other Euphorbiaceae species.