Soybean diseases integrated control with biological and chemical fungicides in differents resistance level of genotypes

Abstract

For “4.0 Agriculture strategies”, the development of integrated crop solutions joining new resistant cultivars, chemical and biological control against diseases, are primordial steps in the preservation of plant yield potential. The objective of this thesis was to evaluate the soybean genotypes response with qualitative (monogenic heritage) and quantitative (polygenic heritage) resistance level for Asian Soybean Rust (ASR) in association with chemical and biological fungicides for Area Under Disease Progress AUDPC) and Grain Yeld. The genotypes studied, consisted of four promising soybean lines (UFU L266, UFU L216, UFU L154, UFU L218) developed by Germplasm Laboratory of Uberlândia Federal University (LAGER / UFU) with partial resistance against Phakopsora pachyrhizi and six cultivars with complete resistance as TMG 7062 IPRO, TMG 7063 IPRO and susceptible to rust, the BMX DESAFIO 8473RSF, BMX FLECHA IPRO, NA 5909 IPRO, MONSOY 7739 IPRO. The study was conducted in two different seasons in field conditions (2017/2018 and 2018/2019). The variables consisted of 40 different management combinations, varying the genetic, chemical (trifloxystrobin + prothioconazole) and biological (Penicillium spp.) controls. The fungicides were sprayed alone (or chemical or biological), or associated (chemical + biological), with an interval of 14 days, in four applications, during the crop development. It was evaluated severity for ASR, powdery mildew and Septoria brown spot and calculated AUDPC (area under disease progress curve), for the genotypes with and without association with fungicides. Grain yield was also evaluated. In the present study was observed different interaction between the genotype, chemical and biological fungicides, for AUDPC and Grain Yeld. Considering only genetic control, genotypes with complete resistance for soybean as TMG 7062 IPRO AND TMG 7063 IPRO with dominant resistance genes performed with the lowest AUDPC levels independent trial season for ASR but didn’t corresponded on higher Grain Yeld levels. Followed, the partial resistance genotypes UFU L266 and UFU L216 performed as second lowest AUDPC level. The cultivars BMX FLECHA IPRO performed as the highest AUDPC levels in both seasons for ASR. According to AUDPC levels on the two seasons evaluated, the diseases pressure influenced the resistance expression. According to data from both season, for genotypes with partial or non- resistance level, was higher influence and interaction with fungicides management. The use of trifloxystrobin + prothioconazole solo and mixture of trifloxystrobin + prothioconazole + biological fungicide (Penicillium sp.) in mostly genotypes tested had thelowest AUDPC levels and highest values for Grain Yield. In both season, genotypes with partialor without resistance to ASR had higher synergic interaction with chemical and biological fungicides.