Hospedabilidade de genótipos de milho aos nematoides Pratylenchus brachyururs, Meloidogyne incognita e Meloidogyne javanica

Abstract

More than 40 species of nematodes are reported parasitizing maize roots in all cultivation areas and damage caused by some of these phytonematoids can lead to a reduction of 20 - 30% in crop productivity. This work aims at evaluating the hostability of maize genotypes to Pratylenchus brachyurus, Meloidogyne incognita and Meloidogyne javanica nematodes. The experiment was conducted in a greenhouse at Instituto de Ciências Agrárias (ICIAG) of the Federal University of Uberlândia, in Umuarama Campus. The experimental design was a randomized block design in a 19x3 factorial scheme with five replications. The tested genotypes were M1 Helix, M2 Helix, M3 Helix, M4 Helix, M5 Helix, M6 Helix, M7 Helix, M8 Helix, M9 Helix, M10 Helix, LG6033PRO2, 3040VIP3, LG6036PRO3, LG36790PRO3, LG36610PRO3, 30F53VYHR, LG36600VIP3, LG3055PRO3 and GNZ2005. Nematode reproduction was evaluated 60 and 90 days after inoculation for Meloidogyne and Pratylenchus nematodes genera, respectively. The Reproduction Factor (RF) was calculated by counting the number of eggs in the soil and root system of the plants of each genotype. Regarding the nematode Meloidogyne incognita the genotypes that presented as bad hosts were M2, M3, M7, M9, LG6033PRO2, 3040VIP3, LG36790PRO3, LG36610PRO3 and LG36600VIP3 with RF ranging from 0.20 to 0.96; for Meloidogyne javanica, except for genotypes M4, LG36610PRO3 and 30F53VYHR, all others behaved as bad hosts with RF < 1; for the nematode Pratylenchus brachyurus, with RF of 0.87, M6 proved to be the worst host, genotypes M7 (1.92), 30F53VYHR (1.89) and GNZ2005 (1.66) presented low nematode multiplication rate. For the crop rotation system, genotypes M3 and LG36610PRO3 may be recommended for areas with Meloidogyne incognita, M5, M6 and LG3055PRO3 in areas with Meloidogyne javanica and for areas with Pratylenchus brachyurus the genotype M6.