Wilson Menezes Aragão

Genetic Relationships among Tall Coconut Palm ( Cocos nucifera L.) Accessions of the International Coconut Genebank for Latin America and the Caribbean (ICG-LAC), Evaluated Using Microsatellite Markers (SSRs)

The diversity and genetic relationships among two accessions of tall coconut palms collected in Brazil and seven accessions introduced from different geographic regions of the world were analyzed using 25 microsatellite primers, 19 of which were polymorphic and detected between 4 and 10 alleles per locus, with an average of 6.57. The observed and expected heterozygosity ranged from 0.25 and 0.40 in the Rennell Islands Tall (RIT) accession to 0.54 and 0.62 in the Polynesian Tall (PYT) accession. The analysis of genetic structure resulted in the formation of five distinct groups. The first group was formed by the accessions Brazilian Tall—Praia do Forte (BRTPF), Brazilian Tall—Merepe (BRTMe) and West African Tall (WAT); the second group consisted of Malaysian Tall (MLT); the third group of RIT; the fourth group of Vanuatu Tall (VTT); and the fifth group of Rotuman Tall (RTMT), Tonga Tall (TONT) and PYT. The dendrogram based on the nearest-neighbor method detected the formation of two main groups and five subgroups, indicating that the genetic relationships of the accessions are based on their geographic regions of origin. The analyses revealed genetic relationships between the accessions collected in Brazil and the accession from Africa, and among palms from South East Asia and the South Pacific, confirming the common origin of these accessions. The information obtained in this study can guide decisions on germplasm conservation activities and the efficient selection of genetically divergent parents for use in coconut breeding programs in Brazil, which are attempting to select for disease resistance, mainly to lethal yellowing, among other characteristics.

RAPD markers in the genetic diversity study of the coconut palm

The coconut palm (Cocos nucifera L.) has a range of genetic divergence, mainly in the colour, shape and size of the finit. However, the current knowledge of such variability is insufficient for a proper characterisation of this species. Over the years, different attempts have been made to use morphological and physiological traits as markers for the study of the genetic diversity in the coconut palm. The studied traits comprised the morphology of finit and vegetative organs, the speed of seed germination, characteristics of the floral biology, and physicochemical properties of the seed. However, these studies have shown that the use of such markers is limited by their susceptibility to environmental influences (Bourdeix et al, 1993).

Variabilidade e comportamento de cultivares de coqueiro anão nos tabuleiros costeiros do norte de Sergipe

The objective of this work was to evaluate the variability of dwarf coconut palm cultivars for morphologic characters in the Coastal Boards of the North of Sergipe State. The experimental design was randomized block, with six cultivars, four blocks and 16 usefull plants/plot. The experiment was driven since 1997, in the Agreste farm in Neopolis (SE). The cultivars dwarf coconut palm red dwarf of Brazil Gramame (AVBrG), of Malaysia (AVM) and Cameroon (AVC), yellow dwarf of Brazil de Gramame (AABrG) and of Malaysia (AAM) and the green dwarf of Brazil de Jiqui (AVeBrJ). For each characteristic, quarterly evaluations from 2001 the 2004, were analyses of variance and estimate of the components of variation phenotypical, genotipycal and environmental. There is variability among the dwarves for the characteristics: alive leaf number (NFV), emitted leaf number (NFE), leaf number dead (NFM), circumference of stem (CircE), length of stem (CE), number of emitted inflorescence (NIE) and number of feminine flowers for inflorescence (NFFI). The AVC and the AVeBrJ presented smaller CE that the other dwarves, important characteristic for reduction of the load of the coconut palm. The AAM was superior to the AAM, AABrG, AVeBrJ and AVC for the CircE, while. The AVC presented inferior behavior in relation to the others for NFV, NFE, CircE and NIE being similar to them for NFFI. The AVeBrJ was superior to the AAM, AVBrG and AVM in relation to NFFI.