Variability of butterfat content in cacao (Theobroma cacao L.): combination and correlation with other seed-derived traits at the International Cocoa Genebank, Trinidad

Abstract

Cocoa butterfat and cocoa powder are key economic products from the seeds of the cacao tree (Theobroma cacao L.). In this study, 323 accessions (comprised mainly of Upper Amazon Forasteros and Refractarios) from the International Cocoa Genebank, Trinidad were characterized for one biochemical and five morphological seed-derived traits. The data were analysed using non-parametric statistics including correlation analysis to identify promising parental candidates for future cacao breeding programmes. The Upper Amazon Forastero group had the greatest proportion of accessions with high butterfat content in cotyledons, whereas Refractario and Trinitario groups tended to contain more accessions with high butterfat content per fruit. The correlation of butterfat content of cotyledons with the dry mass of cotyledons was inconsistent in significance and direction. However, consistent significant positive correlations between butterfat content per fruit, cotyledon size and dry mass of cotyledons were found. The results suggested that butterfat content is a likely trait for independent selection but that selection for increased cotyledon size could lead to the selection of genotypes for high butterfat yield. Several promising accessions exhibited favourable levels of multiple traits and MATINA 1/7, CRU 51, AM 2/91 [POU], CRU 133, EET 58 [ECU] and POUND 18/A [POU] could be recommended as good choices for parental stock in breeding programmes for improving cacao butterfat content.