Uso de resistência genética e fungicidas no controle da ferrugem asiática da soja

Abstract

Soybean is the main agricultural product. However, the productive potential is constantly threatened by soybean disease complexes. Most notably asian soybean rust, caused by the Phakopsora pachyrhizi. The main form of disease control is the use of fungicides. The dependence on this method resulted in an increase in production costs, due to the increase in the number of applications due to the low efficiency of the fungicides over time. Thus, companies in the field of soybean genetic improvement, have been seeking to develop cultivars with efficient levels of tolerance/resistance. Therefore, this work was carried out with the objective of carrying out soybean rust control through the use of tolerant cultivars, integrated with the chemical control of the disease. A randomized complete block experimental design was carried out, with three replicates, arranged in bifactorial scheme (cultivars X treatments). One susceptible cultivar (BMX Delta 59I60 RSF IPRO), one cultivar registered as rust tolerant (TMG7063 IPRO INOX®) and two tolerant soybean lines, of belonging to the germplasm bank of the company GDM Seeds, were used. Six treatments were used. In treatment 1 (control), fungicide applications weren’t applied; treatment 2 (propiconazole + difeconazole) prioritized control end of season diseases; treatments 3 and 5 [(Protioconazole + trifloxystrobin) and (Benzovindiflupyr + Picoxystrobin)] with four and three applications, respectively in each treatment; treatments 4 and 6 [(ciproconazole + trifloxystrobin) and (ciproconazole + Picoxystrobin)] with four and three applications, respectively in each treatment. The genotypes TMG 7063, GDM1 and GDM2 the progress of soybean rust. In the control treatment, a higher incidence was observed in all genotypes. There wasn’t evolution of the disease in the GDM lineages. In the cultivars BMX Delta and TMG 7063, there was a greater evolution in the control and management treatments end of season diseases. A higher level of defoliation was observed in the susceptible genotype. The genotypes BMX Delta, TMG 7063 and GDM1 showed a significant increase in productivity in treatments with fungicides in relation to the control. The productive of thelineage GDM2 wans’t altered with the treatments used, showing the tolerance of this soybean line to soybean rust.