Abstract :
To study the diversity in the in vitro and phenological responses, the model discriminant was used. Six new hybrid cocoa genotypes namely L120-A2, L126-A3, L231-A4, L232-A9, L233-A4 and L330-A9 were analyzed. Three culture media namely PCG1, PCG3 and PCG4, based on DKW basal medium, only differing in hormonal concentration, were sown with staminodes and petals extracted from floral buds. SCA6 and C151-61 were used as controls. The 6 cocoa hybrids were assessed 3 months later by scoring and calculating of the callogenesis and embryogenesis variables. Parameters from variable means were processed via the Principal Component (PCA), Hierarchical Cluster (HCA) and Factorial Discriminant Analyses (FDA). For the PCA, the number of embryogenic explants, embryos number yielded per embryogenic explants, embryogenesis percentage, flowering level, fructification level and leaves flush were
revealed to be pertinent. It was the same in the first year of the study. However, for the FDA, only the number of callogenic explants and leaves flush were showed to be pertinent. This indicates that the pertinentness appears to vary from analysis to analysis. Cocoa hybrids known as L120-A2, L126-A3, L231-
A4 and L330-A9 yielded the highest number of callogenic explants and expressed the highest leaf flush. The first 3 are half sibs of common father IMC67, justifying their belonging to the same group. The discriminant model associated with the analysis is spelt Z1 = - 29.123 + 0.201*Flush + 1.710*Ncal. It
significantly and completely discriminated the clusters in the proportion of 96.20%. The predicting of the membership cluster of new observations, from their number of callogenic explants and leaves flush, was discussed.
Keyword :
Callogenesis; Callus growth media; Leaves flush.