Acta Agronómica
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13094
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Item Comparison of fructification efficiency between reciprocal crosses in Coffea canephora(Universidad Nacional de Colombia, 2023-10-09) Ferrão, Maria Amélia Gava; Fonseca, Aymbiré Francisco Almeida da; Ferrão, Romário Gava; Volpi, Paulo Sérgio; Verdin Filho, Abrão Carlos; Rocha, Rodrigo Barros; Riva-Souza, Elaine ManelliThis study aimed to assess and compare the behavior of superior genotypes of Coffea canephora in terms of fruiting capacity using directed hybridizations in a full diallel design with reciprocals.Hybridizations were performed using 12 possible combinations between genotypes 02, 03, 23 and 83 from the Incaper breeding program. High estimates of the genotypic coefficient of determination in terms of the total number of pinheads per cross (TNP) and fruit set (FS) indicated variability of genetic nature. FS averaged 52,27%, ranging from 31,32% to 82,09%, with the higher rates relating to clone 23 as the male parent. Differences were found between reciprocal crosses in the combinations with genotype 23, which emerged as the donor plant with the best fruiting rate, but poor receiving ability. Clone 83 prevailed as the best receiving plant and the least effective donor. In the comparison of these two genotypes, antagonism was observed in their behavior when they were used as pollen-donor plants (male parents) and pollen-receiver plants (female parents), highlighting their possible maternal effect. Crosses involving clones 02 and 03 showed no differences when used reciprocally. The estimates of genotypic correlations were negative for the four associations involving the FS characteristic, being of greater magnitude with TNP.Item Segregation analysis of molecular markers in a population derived from Coffea liberica Hiern x C. eugenioides L.(Universidad Nacional de Colombia, 2014) Gartner, Germán Ariel López; McCouch, Susan Rutherford; Botero, María del Pilar MoncadaCoffee is a very important crop for the world economy. The commercial coffee production is based on two species, Coffea arabica L. (70%) and C. canephora Pierre (30%). C. arabica is the only allotetraploid (2n=4x=44) species, which has its primary center of diversity in the southwestern Ethiopia highlands. C. arabica is the only species cultivated in Colombia and represents a very important economic and social value. However, C. arabica has a very narrow genetic diversity and therefore, the use of diploid species on coffee breeding is very important because they allow to broad its diversity. In this work, the genetic segregation patterns were evaluated on a population of 101 F1 hybrid plants from a cross between the diploid species C. liberica and C. eugenioides using 618 molecular markers, of which 168 SSRs and 2 ESTs exhibited polymorphic patterns that allowed segregation analysis. Approximately 24% of the loci were null alleles, and the segregation distortion reached 23.5% at a < 0.01. A total of four segregant types were observed, from up to seven possibilities. The origins of null alleles, possible causes of segre gation distortion, different segregation patterns obtained and recombination frequencies are discussed. The knowledge derived from this study allowed to better understand the genetic segregation behavior of these markers with the aim of developing genetic maps that have important applications for coffee breeding programs as well as other commercial crops.