Resumo

MICHELANGELI DE CLAVIJO, Claret C; MEDINA M, Ada M; ARTIOLI G, Paola I  e  MATA, Jonás. Cytogenetic studies of annato embryogenic structures and regenerated plantlets. Agronomía Trop. [online]. 2006, vol.56, n.1, pp.129-137. ISSN 0002-192X.

At this time, a protocol for regeneration of plantlets through somatic embryogenesis from annatto, Bixa orellana L., anthers has been efficiently achieved in different genotypes. In order to verify if plantlets obtained were haploid or if spontaneous chromosome duplication had occurred, cytogenetic studies were made on normal and abnormal embryos, as well as on in vitro cultivated and acclimatized plants regenerated by this technique in the greenhouse. A description of the most efficient processes of prefixation, fixation, hydrolysis and dyeing for each genetic material evaluated is presented. According to mitotic countings, they were all haploids (n=8 chromosomes), showing great stability in chromosome number at different phases. These studies indicate the importance of obtaining relevant information on genetic stability in order to establish protocols using mutagenic agents such as colchicine in breeding programs where dihaploids annatto plants are to be obtained by means of somatic embryo techniques from anther culture.

Palavras-chave : Bixa orellana L; anther culture; haploid.

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