Diversidade genética de Prunus persica por meio de marcadores microssatélites

• Autor(a) principal: Santos, Telma Miranda dos
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4605
• topic: Prunus persica; Diversidade; Microssatélites; Prunus persica; Diversity; Microsatellite; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

The peach tree, a predominantly autogamous plant with an outcrossing rate of less than 5%, is one of the most researched fruit species worldwide. The presence of genetic variability is crucial for progress in plant breeding. Molecular markers are useful for detecting variations in the genome, and microsatellite markers have been shown to be highly efficient in genetic analysis of species such as the peach, which has low genetic diversity. This study aimed to evaluate the informativeness of 22 Simple Sequence Repeats (SSR) loci and assess the genetic similarity between peach cultivars. The study was conducted at the Laboratório de Biotecnologia e Melhoramento Vegetal of the Departamento de Fitotecnia, Universidade Federal de Viçosa, in Viçosa, MG. We calculated the allele frequency, the expected and observed heterozygosities and the average polymorphic information content (PIC). The genetic similarity between two cultivars was calculated by the weighted index, based on the number of common alleles that they share. With these data, a dissimilarity matrix was generated that was used to perform a cluster analysis using the UPGMA hierarchical clustering method. All statistical analyses were performed using the GENES program. Of the 22 SSR primers, eight were polymorphic, and the others were not amplified. A total of 53 alleles were amplified, and the mean number of alleles per locus was 6.625, which ranged between 4 and 9. The allele frequency ranged from 0.0072 to 0.4928 when we used primers UDP98 411 and UDP98 022. The expected heterozygosity ranged from 0.5143 to 0.8579, averaging 0.7105, with the observation at 1.0. The most informative loci were UDP96 005, UDP98 021 and UDP98 407, with PIC of 0.8142, and 0.8258 0.8416, while the least informative were UDP98 022 and UDP98 411 with PIC 0.3963. The average of this parameter for all loci was 0.6553. Data analysis of 53 alleles resulting from the amplification of eight SSR primers did not distinguish all analyzed cultivars. The greatest dissimilarity found was 87.74%. The average dissimilarity was 49.97%, with those between half-siblings at 44.87% and between siblings, 11.85%. There were no differences in the Joia 3 of Joia 4 and Aldrigui of Gaúcho cultivars or of Campinas 1 of Olympia. Peach varieties that had different phenotypic characteristics could not be separated based on information from the primers.