Resumo

SANTANA M, Giovanna F; VELASQUEZ S, Rosalía  e  MATA, Jonás. Carbon source effect on cacao organogenesis and somatic embryogenesis: Citogenetic analysis. Agronomía Trop. [online]. 2010, vol.60, n.2, pp.193-202. ISSN 0002-192X.

The culture of anthers and petals in vitro has been used in this research in order to get a protocol to induce callus formation and somatic embryogenesis in seven venezuelan cacao, Theobroma cacao L., cultivars: OCUMARE-61, OCUMARE-67, CHORONÍ-42, GUASARE-133, CHUAO-2, SANTA CRUZ DE LA VEGA-6 and SANTA CRUZ-10, using DKW media and three different carbon sources: glucose, fructose and sucrose. The randomized desing in a factorial arrangement 3x7 was used. Floral buds of 1.5 to 2 mm of length with microspores in tetrad stage were selected and treated at 12 °C for 48h. To callus and proembriogenic masses development, coconut water and aminoacids respectively was added in culture medium. The results of percentage of expanded explants, necrosis, callus induction and ploidy level were analyzed through Kruskal and Wallis test. In this research, callus formation was diffi cult for both explants and responses varies with cultivars and carbon source. Histological analysis allowed to establish the formation of organogenic callus in some cultivars, but only OCUMARE-61 anthers and CHUAO-2 petioles growing in media supplemented with sucrose, root formation was observed. Somatic embryogenesis was formed from SANTA CRUZ-10 petioles with glucose. The chromosomal analysis of roots revealed haploid number (2n=X=10), indicating the viability to obtain haploid cocoa plants through the anther culture technique, so it is important to study the effect of the physical and chemical factors may have under the induction of shoots and roots of cocoa somatic embryos

Palavras-chave : anthers; haploid; in vitro; petals; Theobroma cacao L.