Abstract

In the Western Amazon, Brazil, Coffea canephora Pierre is the main species cultivated because it has good adaptation to the climate and soils of the region. Among the factors that limit the yield of this crop, Meloidogyne or root-knot nematode, caused by the root knot nematode, is an aggressive disease present in the state of Rondonia. The aim of this study was to evaluate the reaction of fifteen clones of C. canephora, belonging to the cultivar BRS Ouro Preto, to Meloidogyne incognita (Est I2). Therefore, six seedlings with six months of growth in a nursery from each one of the clones of the cultivar were transferred to pots containing a sterilized substrate in a greenhouse. Following the same design, three clonal genotypes selected from the cultivar IAC Apoatã (C. canephora botanical variety Robusta) served as resistant controls, and seedlings of C. arabica of the Obatã line and tomato (Solanum lycopersicum) cv. Santa Clara (20 days after germination) as susceptible controls, for a total of 120 pots. A 10 ml suspension containing 5000 eggs of M. incognita was inoculated on each plant, and after 150 days, they were evaluated with regards to root fresh weight (FWR), number of galls (NG), number of eggs (NE), and the nematode reproduction factor (RF = final population/initial population). Except for the clone K98M-0061, which exhibited galls (29.17), all the clones of the variety BRS Ouro Preto showed resistance at levels equivalent to those of the controls of the var. Apoatã (RF <1) and good root development. Thus, it can be concluded that the total composition of clones of the variety BRS Ouro Preto is resistant to M. incognita in Rondonia.

Key words: Coffee, Meloidogyne, plant selection.