English

Abstract

The objective of this study was to estimate genetic parameters and predict the genetic gains of coffee plant progenies using characters that are targeted in coffee breeding. The experiment was conducted in an area naturally infested with Meloidogyne exigua on Ouro Verde Farm, which is located in the municipality of Campos Altos in the state of Minas Gerais- Brazil. Twenty-three progenies that were potentially resistant to root-knot nematodes were used in the study, and seven commercial cultivars were used as controls. The evaluated progenies are in the fourth generation of a cross between ‘Híbrido de Timor’ and ‘Catuaí’, and they were provided by the coffee plant-breeding program conducted in Minas Gerais. The following characters were evaluated in the 2010 to 2011 and 2011 to 2012 crops: Productivity per processed coffee bags per hectare; percentage of grains at the berry stage; percentage of floating grains; grains size; and plant vigor. Furthermore, the number of M. exigua eggs per root gram was evaluated in the latter crop. The following genetic parameters were evaluated: Coefficient of environmental variation; phenotypic variance; genotypic variance; broad sense heritability; coefficient of genetic variation; and variation index. Gains by direct and indirect selection and the selection index, based on the sum of ranks of Mulamba and Mock, were used to estimate the genetic gain prediction. The progenies exhibited large genetic variability for the assessed traits. The index based on the sum of ranks presented higher simultaneous gains in relation to direct and indirect selection. The progenies (H493-1-2-2, H514-7-4-5, H518-2-10-1, and 514-5-2-4) were the most promising in the area infested by M. exigua and were identified for generational advancement based on the two procedures of analytical gain prediction.   Key words: Coffea arabica, selection index, breeding.