IS THERE GENETIC VARIABILITY IN DWARF COCONUT ACCESSIONS PRESERVED IN BRAZIL?1 1 Paper extracted from the doctoral thesis of the first author.

HÁ VARIABILIDE GENÉTICA EM ACESSOS DE COQUEIRO-ANÃO CONSERVADOS NO BRASIL?

Kamila Marcelino Brito Sobral Manoel Abilio de Queiroz Izaias da Silva Lima Neto Ronaldo Simão de Oliveira Semíramis Rabelo Ramalho Ramos About the authors

ABSTRACT

Dwarf coconut tree is the main variety for commercial use in Brazil, which ranks fourth in world coconut production. However, the genotypes used still have limitations and genetic variability is required. The aim of this study was to estimate the genetic variability in dwarf coconut accessions preserved at the Germplasm Bank of Brazil at different harvesting times and using agronomic descriptors of plant and fruits. The accessions Brazilian Green Dwarf-Jiqui, Cameroon Red Dwarf, Malayan Red Dwarf, Brazilian Red Dwarf-Gramame, Brazilian Yellow Dwarf-Gramame, and Malayan Yellow Dwarf were assessed by means of 30 descriptors Variance analysis was performed and the genetic diversity was quantified by using the Mahalanobis’ generalized distance and expressed by means of UPGMA clusters, Tocher optimization, and canonical variables. The maximum likelihood analysis was used to estimate the components of variance with the data of each plant in a sample of 11 descriptors of great importance for the genetic improvement of the coconut tree. A phenotypic divergence was found among the accessions using the UPGMA clusters, Tocher optimization and graphic dispersion obtained with canonical variables. The use of the maximum likelihood analysis confirms the existence of genetic variability in the accessions for the descriptors fruit polar and equatorial diameter, nut polar diameter, total fruit weight, and epicarp thickness, which presented a heritability varying from 0.17 to 0.39. There is a possibility of genetic gains with the selection of these traits for use of accessions in breeding programs.

Keywords:
Cocos nucifera L; Phenotypic traits; Multivariate analysis; Germplasm; Plant genetic resources

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