Effect of the flower bud length on cocoa somatic embryogenesis

Abstract

The traditional propagation methods (sexual and asexual) in the cultivation of Cocoa, Theobroma cacao L., have not been the most convenient because plants grow up with undesirable agronomic characteristics by the producers. At present, the somatic embryogenesis seemed to be the most suitable way to produce cocoa plants of economic importance. The objective of this study was to determine the effect of the length of the flower bud (BF) has on the induction of cocoa somatic embryos (IES) from the floral structure of the genotypes Ocumare-61, Ocumare-67, Choroni-42, and Choroni-163. The callus induction (IC) was achieved by staminodes explants growing in DKW medium supplemented with TDZ, 2,4-D y 80 g l-1 of saccharose. The proembriogenic structures were transferred to DKW medium supplemented with amino acids and KNO , under conditions of darkness and 27±2 ºC to object of inducing the development of somatic embryos and to diminish the necrosis of the tissue by the effect of phenolics products. After a month of culture, a genotypic response was observed on the induction of callus, the best answer was observed in the genotype OC-61, continued by OC-67, CHO-43, and CHO-163. The last one showed the smallest percentage of the formation of callus per experimental unit. An organogenic response was observed, roots formation, in all genotypes evaluated; when these calli were cultivated in a medium for embryos development, the percentage and average number of roots for explante varied with the genotype