African Journal of Biotechnology Vol. 4 (11), pp. 1256-1268, November 2005          
ISSN 1684–5315 © 2005 Academic Journals

Full Length Research Paper

Genetic relationships among Ethiopian mustard genotypes based on oil content and fatty acid composition

Tsige Genet¹*, M.T. Labuschagne¹ and A. Hugo²

Departments of ¹Plant Sciences and ²Microbiology, Biochemistry and Food Science, University of the Free State, P.O.Box 339, Bloemfontein 9300, Republic of South Africa.

*Corresponding author. E-mail: Tsigegenet@yahoo.com, Tel: +251-8-380591; Fax: +251-8-380235.

^ΏCorresponding author current address: Amhara Regional Agricultural Research Institute, Adet Research P.O.Box 1626, Bahir Dar, Ethiopia. Tel: +251-058-3380591; Fax: +251-058-3380235.

Accepted 12 September, 2005

Quantification and classification of genetic diversity among genotypes is essential for parental selection in breeding programs. The objective of this study was to classify and cluster Ethiopian mustard genotypes according to their fatty acid composition, and to assess the genetic relationship between the genotypes. This study revealed wide variation in fatty acid composition. Principal component analysis showed that desaturation ratio, elongation ratio, monounsaturated fatty acids, oleic desaturation ratio, and vaccinic acid had the highest loading in the first component that accounted for 39.28% of the total variation. For the second principal component stearic acid, saturated fatty acid, palmitic acid, oleic desaturation ratio, polyunsaturated fatty acids, and α-linolenic acid had the highest loading that accounted for 30.97% of the total variation. Five principal components explained 96.01% of the total variation. The dendrogram generated by the UPGMA cluster analysis grouped B. carinata genotypes into 11 distinct clusters. The pair-wise mean genetic distance estimates based on fatty acid composition was 1.080.02. The information generated from this study can be used to plan crosses and maximize the use of genetic diversity and expression of heterosis.

Key words: Brassica carinata, capillary gas chromatography, fatty acids, genetic diversity, oil content.