Genetic-diversity assessed by microsatellites in tropical maize populations submitted to a high-intensity reciprocal recurrent selection |
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Authors: | Luciana Rossini Pinto Maria Lucia Carneiro Vieira Cláudio Lopes de Souza Jr Anete Pereira de Souza |
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Institution: | (1) Departamento de Genética, C.P. 83, Universidade de São Paulo, Escola Superior de Agricultura `Luiz de Queiroz', 13400-970 Piracicaba, Brazil;(2) Departamento de Genética e Evolução, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, C.P. 6010, 13083-970 Campinas, Brazil |
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Abstract: | BR-105 and BR-106 are important tropical maize populations, which were submitted to a high-intensity reciprocal recurrent
selection, generating the IG-3 and IG-4synthetics. Using 30-microsatellite loci,we measured and compared the genetic diversity
of these populations and their synthetics. The populations did not differ significantly regarding the amount of genetic diversity.
As a consequence of selection, genetic variability losses, in terms of mean number of alleles per locus,proportion of polymorphic
loci, and gene diversity did occur and were greater in the synthetic IG-3 than IG-4. In the synthetics, the number of loci
in adherence to Hardy-Weinberg proportions was superior to that observed in the populations. The Wright's mean fixation index
was higher than the mean value expected for outcrossing species (5%) indicating as light excess of homozygotic individuals
in both populations. The genetic distances confirmed the favourable effects of one cycle of recurrent selection, as the synthetics
became more isolated in comparison to the original populations.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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Keywords: | genetic diversity microsatellites recurrent selection tropical maize |
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