GENETIC DIFFERENTIATION AMONG ECUADORIAN THEOBROMA-CACAO L ACCESSIONSUSING DNA AND MORPHOLOGICAL ANALYSES

The quality of Ecuadorian cacao is presently threatened by the introdu ction of hybrid material. An estimation of genetic diversity in Ecuado r is required in order to avoid the loss of fine flavored cocoa. Genet ic variability amongst 60 Ecuadorian genotypes of Theobroma cacao has been evaluated using molecular and phenotypic markers. The two distanc e matrices derived from the molecular and phenotypic data were found t o be correlated (R-2 = 0.5). Dynamic clustering analyses classified th e genotypes in two or three groups depending on the markers used. The genotypes coming from Sebastian Arteaga (SA) and Balao Chico (BCH) pla ntations appeared related to each other suggesting a common genetic or igin. They also may be considered as a distinct group with high RFLP h omozygosity. The EETP (Estacion Experimental Tropical Pichilingue of E cuador) collection was comprised of more variable genotypes possessing variable heterozygosity levels. The low heterozygous genotypes may be genetically related to SA and BCH trees, whereas the higher heterozyg ous genotypes may have resulted from hybridizations between original N acional material of Ecuador and genotypes imported from Trinidad at th e beginning of the century. Thus genetic introgression may have occurr ed giving rise to a range of variation between Nacional and hybrid for ms.