Diversidade genética e análise de dialelo para escolha de progenitores no melhoramento de Coffea arabica
Os programas de melhoramento genético do cafeeiro têm como principal objetivo a obtenção de cultivares com características agronômicas e tecnológicas de interesse, qualidade superior de bebida e resistência a pragas e doenças, aliadas a elevado potencial produtivo. Uma ferramenta útil para auxiliar...
|Nível de Acesso:||openAccess|
Universidade Federal de Viçosa
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|Citação:||MEDEIROS, Alexsandra Correia. Diversidade genética e análise de dialelo para escolha de progenitores no melhoramento de Coffea arabica. 2016. 59 f. Dissertação (Mestrado em Genética e Melhoramento) - Universidade Federal de Viçosa, Viçosa. 2016.|
|Resumo inglês:||The main objectives of coffee breeding programs is to obtain cultivars with good agronomic traits, better cup quality and resistance to pests and diseases combined with high yield potential. A useful tool to assist the selection of promising parents for these programs is the study of genetic diversity using molecular markers. Another method used is the diallel cross. Diallel shave been applied to obtain information on the genetic potential of cultivars, as well as its combination capacities that result in hybrids of promising segregating populations. Thus, this study aimed to apply these two methods, the analysis of genetic diversity and circulant diallel to assist Coffea arabica breeding programs. Molecular markers were also used for certification of hybrids. Twelve SSR (Simple Sequence Repeats) molecular markers were used to assess the genetic diversity of 76 potential parents and certificate 48 potential hybrids. The analysis of genetic distance matrix and the dendrograms showed that Catiguá MG2 x Acauã, Catiguá MG2 x Topazio MG 1190, Catiguá MG2 x Arara, Catiguá MG2 x Bourbon Amarelo and Catiguá MG2 x Tupi Ferrero are the crosses that optimize the genetic distance between parents. With molecular markers data, seven potential hybrids showed to be result of self-pollination and the remaining 41 plants were identified as true hybrids. The circulant diallel analyses were assessed with eight parents and 12 hybrids, using ten agronomic traits. The general and specific combining abilities were estimated, as well as the means of the parents, hybrids and predicted hybrids for each trait. For the main agronomic trait (vegetative vigor and yield), crossings that should be prioritized are between the parents Catiguá MG2 and UFV 311-63, and between Catiguá MG2 and Acauã Novo based on the genetic parameters estimation. A correlation analysis was performed to study the relationship between molecular genetic distance, phenotypic genetic diversity, phenotypic mean and combining ability of the plants evaluated in diallel. There was a greater correlation between genetic distance and phenotypic mean of the traits evaluated and combining ability, when compared to phenotypic distance. Furthermore, the most strongly correlated traits with genetic diversity were vegetative vigor and yield.|