|Authors: ||A.S. Lédo, S.R.R. Ramos , L.E.C. Diniz, J.L.K. Konan , M.L. George|
|Keywords: ||Cocos nucifera L., genetic resources, in vitro culture, zygotic embryo, contamination|
The present work is a partial report for the introduction of eleven accessions of dwarf coconut and one accession of giant coconut tree into the International Coconut Genebank for Latin America and the Caribbean (ICG-LAC), a partnership between Embrapa Coastal Tablelands (CPATC) and Bioversity International, coordinated by Coconut Genetic Resources Network (COGENT). These accessions, originated from the International Coconut Genebank for Asia, India and Oceania (ICG-AIO), situated at Ivory Coast, were introduced in Brazil through zygotic embryos in November 2008. The mature fruits and endosperm cylinders with embryos were submitted at Ivory Coast to a phytosanitary treatment process according to international technical recommendations for safe movement of vegetal germplasm.
At the Laboratory of Plant Tissue Culture of CPATC, the embryos were excised, surface sterilized and inoculated in Y3 culture medium.
The first evaluation occurred after nine days of inoculation, and it was verified that 1.38% of the embryos were contaminated by fungi and 15.30% by bacteria.
After 12 months of inoculation variation of in vitro develop¬ment was observed within and among accessions and a high percentage of non-germinated and oxidated embryos.
The normal germination percentage varied from 3.33% for ‘Niu Leka Dwarf’ to 33.3% for ‘Malayan Green Dwarf’ accessions.
The non-germinated embryos percentage varied from 18.47% for ‘Tahitian Red Dwarf’ to 47.72% for ‘Sri Lanka Green Dwarf’ accessions.
After 12 months, the contamination was higher for ‘Niu Leka Dwarf’ (70%). The percentage of non-germinated and oxidated embryos varied from 18.47% (‘Tahitian Red Dwarf’) to 47.72% (‘Sri Lanka Green Dwarf’). The great number of collected cylinders with exposed embryos (not protected by endosperm) and cracked endosperm, in addition to the long storage time (7 to 11 days) from collection to inoculation, favored bacterial proliferation.
The non uniform stage of fruits/embryos maturation contributed to high variation of in vitro development.
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