Desempenho de linhagens de soja em ambientes com nematoides das galhas

Abstract

Soybeans are the main crop in Brazilian agribusiness, but they are facing phytosanitary problems, among which the increase in areas with the presence of nematodes, mainly of the Meloidogyne genus, stands out. Continuous research is essential to develop new management strategies and cultivars that are more resistant to these pathogens, making it essential to have soybean improvement programs aimed at obtaining cultivars capable of increasing productivity in areas with the presence of root-knot nematodes. In this context, the objective was to evaluate in the field the behavior of soybean cultivars/lines in terms of severity for root-knot nematodes, comparing the results with phenotypic data obtained in a greenhouse, with the purpose of validating the phenotyping method for use in breeding programs aimed at obtaining resistant cultivars. The field experiments were conducted in the municipalities of Manoel Viana-RS and São Francisco de Assis-RS, in areas naturally infested with nematodes M. incognita and M.javanica. In these areas, reboleiras with a higher incidence of nematodes were visually identified, with prior preparation for the installation of the experiment. The greenhouse tests were conducted in Cambé-PR at the GDM plant health laboratory. The soil was previously prepared for the multiplication of root-knot nematodes, and then used to prepare the pots, in which the lines and cultivars used in the present study were sown. In both experiments, eleven cultivars/experimental lines were used. The genotypes were evaluated for gall intensity using the rating scale from 0 to 5, proposed by the National Cultivar Protection Service, MAPA (2012). Regarding the phenotypic behavior of the tested strains, both in field and greenhouse experiments, the lowest gall index (GI) was observed in SBI225105 and, in turn, the highest score in the SBI225110 strain for M. incognita. Considering M. javanica, all strains evaluated were classified as susceptible.