Submitted to: Plant Genetic Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2008
Publication Date: 5/19/2008
Citation: Khan, N., Motilal, L.A., Sukha, D.A., Bekele, F.L., Iwaro, A.D., Bidaisee, P., Umaharn, L.H., Grierson, L.H., Zhang, D. 2008. Variability of butterfat content in cacao (Theobroma cacao L.): combination and correlation with other seed-derived traits at the International Cocoa Genebank, Trinidad. Plant Genetic Resources. http://dx.doi.org/10.1017/S1479262108994132. Interpretive Summary: Cocoa is an important tropical crop since it is the source of cocoa butter and powder for the confectionery industry. Genetic resources of cocoa are important for breeding new cocoa varieties and thus are of great importance for a sustainable cocoa production. Understand the variation of cocoa butterfat and powder in the germplasm collection is essential for breeding new cocoa varieties with improved yield and quality of cocoa butterfat and powder. The present study analyzed 323 cocoa varieties from the International Cocoa Genebank, Trinidad for cocoa butterfat and cocoa powder, as well as other related economic traits. The results improved our understanding of the range of cocoa butterfat and cocoa powder in the germplasm collection. It also clarified the relationship among the traits associated with cocoa butterfat and cocoa powder yields. Several promising varieties with multiple traits were identified as good candidates for parental stock for breeding programs. This information will be useful to cocoa breeders, cocoa farmers and the chocolate industry.
Technical Abstract: Cocoa butterfat and cocoa powder are key economic products from the cacao tree (Theobroma cacao L.). In this study, 323 accessions from the International Cocoa Genebank, Trinidad were analysed for bean number (BNO), bean size as bean length x bean width (BLW), bean mass (BM), bean mass per fruit (BMF), seed butterfat content (%BF), butterfat content per fruit (BFF) and pod index (PI) using non-parametric statistics including correlation analysis to identify promising parental candidates. BM and BNO were not correlated suggesting independent selection for these traits. BLW was positively correlated with BM and negatively correlated with PI (both at P<0.001) suggesting simultaneous improvement of these three traits. Upper Amazon Forastero population had the greatest proportion of high %BF whereas Refractario and Trinitario tended to contain more BFF accessions. BFF or %BF was not generally correlated with any of the other studied traits except for BFF and BLW (rs = 0.46) in Upper Amazon Forasteros. Butterfat content is suggested to be an independently selected trait in Theobroma cacao L. Several promising accessions combined favourable levels of multiple traits with MATINA 1/7, CRU 51, AM 2/91, CRU 133, EET 58 and POUND 18/A as good choices for parental stock in breeding programmes.