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Resumo -O objetivo deste trabalho foi avaliar a adaptabilidade e a estabilidade fenotípicas para a produtividade de cultivares de cafeeiro do grupo Catuaí, pela metododologia de Annicchiarico.

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The nematode Meloidogyne exigua infests Arabica coffee (Coffea arabica L.) plants, leading to severe growth reduction in young trees and decreased bean yield. We investigated the responses of coffee plants to this nematode and estimated the genetic gain in progenies derived from the cross between the cultivar Catuaí and the Timor hybrid. We evaluated 85 F4:5 progenies; the cultivars Mundo Novo IAC 379‐19 and Catuaí Vermelho IAC 99 were used as susceptible controls, and Paraíso MG H 419‐1 and IPR 100 were used as resistant controls. Progeny responses were evaluated using the gall index (GI), reproduction factor (RF), reproduction factor reduction (RFR), and number of eggs and juveniles (J2) per gram of roots (NEJGR). The cultivars IPR 100 and Paraíso MG H 419‐1 and 75 progenies were resistant to M. exigua. Little or no segregation for resistance was observed within the progenies, indicating potential homozygosity at this locus. The GI, RF, RFR, and NEJGR showed high genotypic correlation. The correlated response of decreased NEJGR when selected indirectly by GI was higher than that by direct selection. The GI scale allowed genetic gain to decrease the nematode population and increase resistance; therefore, it can be used as a selection criterion. Linear regression showed that the NEJGR mean was reduced by a value of 450 per selection cycle, which led to a change in the phenotypic mean and explained 95% of the variation. Thus, successive selection cycles could prevent nematode development in coffee tree roots.

SUMMARYRoot-knot nematodes represent a serious threat to world coffee production, especially Meloidogyne incognita and M. paranaensis. Most cultivars of Coffea arabica are highly susceptible to these parasites and cultivation in infested areas has only been possible with the use of resistant C. canephora rootstocks. In this research, three elite clones of C. canephora, selected in areas infested by M. incognita and M. paranaensis, were evaluated in controlled conditions to assess levels of resistance against two populations of M. paranaensis, four populations of M. incognita and a mixed population of both species. The three clones were resistant to both species, but CcK1 and CcR2 were considered most promising because their vegetative growth was not impaired by nematodes.

<p>Coffee cultivars that are better adapted and more productive can help reduce production costs and make coffee cultivation more profitable. The Mundo Novo cultivar has stood out as one of the most productive cultivars of <em>Coffea arabica</em> L. Therefore, the aim of this work was to select Mundo Novo progenies with high bean yield capacity and with other agronomic characteristics of interest. We evaluated the bean yield, seed size, plant height, upper and lower canopy diameter, stem diameter, and plant vigor of 24 F₄ progenies and one check cultivar. The experimental design consisted of a randomized complete block design with three replications and experiments were carried out in two sites: São Sebastião do Paraíso (SSP) and Três Pontas (TP), MG, Brazil. The mixed model approach was used to calculate the genotypic value for each progeny, after which the selective accuracy and genetic gain of the two best progenies in each trait were calculated. To summarize, the simultaneous selection index of Mulamba and Mock was used to select the two most promising progenies at each site. In general, the genetic gain was higher at SSP than at TP. In SSP, the most promising progenies were 1 [IAC376-2 (M. Novo) x IAC386-17 (M. Novo)] and 20 [IAC382-10 (M. Novo) x IAC388-20 (M. Novo)]. In TP, the most promising progeny was 22 [H1535/181 (M. Novo) x (S795) 1344/10/5], together with the check (Mundo Novo IAC379/19). The highest selection gain was expressed for bean size (the percentage of beans retained in sieve 17).</p>

-Brazilian arabica coffee production is based on a set of highly

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