Parâmetros genéticos e alterações nas freqüências alélicas em três ciclos de seleção divergente para tolerância ao alumínio em milho

• Autor(a) principal: Almeida, Ramon Vinicius de
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4672
• topic: Marcador molecular; Estresse abiótico; Microssatélite; Molecular marker; Abiotic stress; Microsatellite markers; CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA QUANTITATIVA

Aluminum (Al) toxicity is one of the major constraints for agriculture on acid soils, which occupy large regions of the world s agricultural area. At low pH values associated with these soils Al3+ is solubilized into soil solution and is toxic to plants inhibiting root growth and crop yield. Cultivars genetically adapted to acid soils may offer an environmental compatible solution. The aims of this work were (1) to estimate parameters and genetics gains in three cycles of divergent selection to aluminum tolerance and (2) to identify changes in allelic frequencies at five loci near a QTL in chromosome 5 of maize that explain 13% of the Al tolerance. The phenotypic index employed was relative seminal root length (CLR) obtained from nutrient solution. Simple sequence repeats (SSR) were used to detect linkage disequilibrium between marker and QTL. An expressive genetic gain of 49,15% was observed from base population to first generation. This evidence is characteristic from traits that have oligogenic inheritance. Shifts in allelic frequencies in 4 loci in first generation and in all loci, in second generation were exclusively due to effects of genetic drift.