Occurrence of foliar diseases in soybean cultivars in western São Paulo State
Occurrence of foliar diseases in soybean cultivars in western São Paulo State
-
DOI: https://doi.org/10.22533/at.ed.09736226010414
-
Palavras-chave: Glycine max, manejo integrado, resistência genética
-
Keywords: Glycine max, integrated management, genetic resistance
-
Abstract: Soybean cultivars may exhibit differential susceptibility to diseases depending on the production environment. Therefore, the occurrence of foliar diseases was evaluated in 24 soybean cultivars grown in the municipalities of Assis, Cândido Mota, and Palmital, São Paulo State, Brazil, aiming to identify differences in cultivar response and generate information to support growers and regional technicians in selecting cultivars for future growing seasons in the region. A randomized complete block design was used, with 24 cultivars and four replications per trial, and means were grouped using the Scott–Knott test at 5% probability. The evaluated traits were incidence and severity of the main diseases, with incidence characterized by the presence of visual disease symptoms and severity assessed using diagrammatic scales. Significant differences were observed among diseases, cultivars, and growing areas. The main foliar diseases observed across the three growing areas were downy mildew, cercospora blight, target spot, and anthracnose, with mean incidences of 28.9, 14.0, 11.7, and 1.8%, respectively. Disease severity was generally low and below 0.5% in most cultivars. Cultivars M 7222 I2X, GF 67IX26 I2X, GH 6630 I2X, TMG GUANANDI I2X, and HO PRATA I2X stood out by showing lower occurrence of the main diseases, suggesting a greater level of tolerance. Among the evaluated environments, Palmital showed greater disease intensity. Other diseases occurred sporadically and at low frequency, indicating the effectiveness of the phytosanitary management adopted and/or the late occurrence of infections. These results highlight the importance of continuous regional evaluations under different growing conditions to obtain consistent information regarding the susceptibility of new soybean cultivars to major diseases.
- Ivan Herman Fischer
- Juliana Cristina Sodario Cruz
- Sergio Doná