Biochemical characterization of some Nigerian <i>Corchorus L.</i> species

Abstract

Corchorus (L) is an important vegetable, grown mainly for its leaves. It contributes to the dietary requirements of the local populace as well as local economy. Five accessions, three labeled NHCO3, NHCO25 and NHCO26 obtained from the Plant Genetic Resources Unit of Nigerian  Institute of Horticulture (NIHORT), Ibadan and two BN/OD/01 and  ON/OD/02 obtained from home gardens were evaluated for their  proximate: ash, moisture, carbohydrate, protein, lipid and fibre contents.
Result showed that all biochemical parameters evaluated vary significantly (P0.05) among the accessions. Accession NHCO25 had the highest ash (8.82 ± 0.87), lipid (10.83 ± 1.27) and moisture content (11.31 ± 0.93). Accession NHCO26 had the highest carbohydratecontent (17.94 ± 0.17)
but is low in crude fibre content. ON/OD/02 had the highest protein content (62.96 ± 4.80). The highest crude fibre content was obtained from  accession NHCO3. Data obtained were standardized and subjected to principal component analysis to determine which proximate parameter accounted most for the variation observed in the five accessions studied. PCA axes 1, 2, and 3 accounted for 96.25% of the total variation. At PCA I ash and lipid accounted for the variations, fibre in PCA II and moisture in PCA III. Single linkage cluster analysis was accessed to group accessions based on similarities and differences in characters. A resulting dendrogram from the data reflected a clustering pattern of three cluster groups. Cluster I contained accession NHCO26, cluster II contained accession NHCO3, BN/OD/01 and ON/OD/02; while cluster III contained accession NHCO25. Accession NHCO25 and NHCO26 were the most distinct and diverse of all the accessions and could serve as sources of variability in character for Corchorusgermplasm improvement. These results revealed that the  accessions of Corchorus evaluated contain appreciable amounts of lipids,
ash, fibre and moisture contents and these components could account for the variability among these accessions. This study suggests proximate analysis as another window for determining variability among crop plants.

Key words: Corchorus, leafy vegetable, biochemical characterization,  principal component analysis, single cluster analysis.