Characterization of resistance response of Coffea canephora genotypes to Meloiddogyne incognita (Est I2) root-knot nematode

Abstract

ABSTRACT:Meloidogynose is prominent among the factors that limit yield in C. canephora in the western Amazon, Brazil. It is caused by species of "root-knot nematode"; the most important and aggressive of these species for coffee is M. incognita. The aim of this study was to assist the selection of resistant genotypes by characterizing the reaction of 32 C. canephora clones to M. incognita (Est I2). These genotypes are selected plants from the Germplasm Bank of Embrapa Rondônia of the botanical varieties Conilon, Robusta and intervarietal hybrids. The experiments were conducted under greenhouse conditions by inoculating six seedlings for each clone with 10 ml of suspension containing 5000 eggs of a pure inoculum of M. incognita. At 150 days after inoculation, evaluations were made of fresh weight of roots (FWR), total number of galls (NG), total number of eggs (NE), and the nematode reproduction factor (RF=final population/initial population). In contrast with the susceptible controls of arabica coffee (RF=1.2) and tomato plants (RF=31.3), six clones of the Conilon botanical variety, five clones of the Robusta botanical variety and eight intervarietal hybrids reacted as resistant to M. incognita, exhibiting RF<1 and a reduced number of galls (NG mean = <10). The clones identified as resistant in this study were integrated in the coffee breeding program in Rondônia for development of cultivars resistant to the root-knot nematode adapted to tropical conditions. Index terms: Coffee, meloidogynose, plant selection, plant breeding, Rondônia. Caracterização da resposta de resistência de genótipos de Coffea canephora ao Nematoide-das-Galhas Meloidogyne incognita (Est I2)RESUMO: Entre os fatores que limitam a produtividade do C. canephora na Amazônia Ocidental destaca-se a meloidogynose, causada por espécies do "Nematoide-das-Galhas", dentre as quais a mais importante e agressiva ao cafeeiro é M. incognita. O objetivo desse trabalho foi caracterizar a resistência à M. incognita (Est I2) de 32 genótipos das variedades botânicas Conilon, Robusta e híbridos intervarietais provenientes do Banco de Germoplasma da Embrapa Rondônia. Os experimentos foram realizados em casa de vegetação com a inoculação de seis mudas para cada clone com 10 ml de suspensão contendo 5000 ovos de inóculo puro de M. incognita. Cento e cinquenta dias após a inoculação foram avaliados o peso fresco (PF), o número de galhas (NG), o número de ovos (NO) e o fator de reprodução do nematoide (FR= população final/população inicial). Em comparação com as testemunhas suscetíveis de café arábica e do tomateiro (FR=1,2 e 31,3, respectivamente), os clones da variedade botânica Conilon (694, 160, 837, 46, 909, 890), da variedade botânica Robusta (1111, 8152, 8192, 10141, 8152) e os materiais híbridos (844, 1005, 169, 54, 453, 120, 193, 636) reagiram como resistentes à M. incognita, apresentando FR<1 e reduzido número de galhas (NG médio = <10). Os clones identificados como resistentes foram integrados ao programa de melhoramento genético do cafeeiro visando o ...

Resistance of new Coffea canephora clones to root-knot nematode (Meloidogyne incognita) in the western amazon

“…As expected, the treatments used as resistant and susceptible controls showed significant differences in the resistance traits means ( Table 2). The reproduction factor of 0.37 of the Apoatã-2258 and BRS2299 treatments indicates that these clones, also classified as resistant by Santos et al, (2018a), showed resistance to M. incognita. Such results confirm the resistance of the Apoatã cultivar which has been used as an alternative in control of root-knot nematodes.…”

“…Plant selection of C. canephora genotypes with resistance to root knot nematodes may be considered in the development of new resistant cultivars (Lima et al, 2015;Fatobene et al, 2018). Of the 32 genotypes of C. canephora evaluated by Santos et al (2018a), it was observed that nine showed higher susceptibility to M. incognita. In a study of 73 wild Coffea spp, plants were identified 18 genotypes of C. canephora resistant to Meloidogyne spp.…”

Coffea canephora breeding: estimated and achieved gains from selection in the Western Amazon, Brazil

“…classification and nematode resistance. The full-sib clones G10-P8 and G13-P8 of high field yield, also differentiated by their high sieve classification, rust resistance, and uniformity of maturation (SANTOS et al, 2017, SANTOS et al, 2018. In 2019, the clones G10-P8, G13-P8, G14-P4, G16-P7, and G20-P7 were registered in the Ministry of Agriculture and recommended for planting in Western Amazon regions (MAPA/RNC, 2019).…”

Amazonian Robustas - new Coffea canephora coffee cultivars for the Western Brazilian Amazon

“…Less aggressive and of difficult diagnosis, Meloidogyne exigua is the most widespread species that causes damage to Coffea arabica plants. The species Meloidogyne incognita -EI2 has occurred most in C. canephora cultivation in the state of Rondônia (Santos et al 2018). AL Teixeira et al…”

“…The resistance response to nematodes was evaluated based on tests conducted in a greenhouse in Porto Velho and Ji-Paraná, RO. Clones considered susceptible through observation showed root knots, eggs, and juveniles of the nematode in the roots exceeding the established standards (Santos et al 2018). When choosing clones for planting, care should be taken when using clones considered to be very susceptible in areas whose history indicates high nematode infestation (Table 4).…”