Evaluation of the Combined Effect of Heterodera glycines and Macrophomina phaseolina on Soybean Yield in Naturally Infested Fields with Spatial Regression Analysis and in Greenhouse Studies.
Phytopathology
; 110(2): 406-417, 2020 Feb.
Article
em En
| MEDLINE
| ID: mdl-31535924
Heterodera glycines, the soybean cyst nematode, and Macrophomina phaseolina, causal agent of charcoal rot, are economically important soybean pathogens. The impact and effect of these pathogens on soybean yield in coinfested fields in the Midwest production region is not known. Both pathogens are soilborne, with spatially aggregated distribution and effects. Spatial regression analysis, therefore, is an appropriate method to account for the spatial dependency in either the dependent variable or regression error term from data produced in fields naturally infested with H. glycines and M. phaseolina. The objectives of this study were twofold: to evaluate the combined effect of H. glycines and M. phaseolina on soybean yield in naturally infested commercial fields with ordinary least squares and spatial regression models; and to evaluate, under environmentally controlled conditions, the combined effect of H. glycines and M. phaseolina through nematode reproduction and plant tissue fungal colonization. Six trials were conducted in fields naturally infested with H. glycines and M. phaseolina in Ohio. Systematic-grid sampling was used to determine the population densities of H. glycines and M. phaseolina, and soybean yield estimates. Though not used in any statistical analysis, M. phaseolina colony forming units from plant tissue, charcoal rot severity, and H. glycines type were also recorded and summarized. In two greenhouse experiments, treatments consisted of H. glycines alone, M. phaseolina alone, and coinfestation of soybean with both pathogens. Moran's I test indicated that the yield from five fields was spatially correlated (P < 0.05) and aggregated. In these fields, to account for spatial dependence, spatial regression models were fitted to the data. Spatial regression analyses revealed a significant interaction effect between H. glycines and M. phaseolina on soybean yield for fields with high initial population densities of both pathogens. In the greenhouse experiments, H. glycines reproduction was significantly (P < 0.05) reduced in the presence of M. phaseolina; however, soybean tissue fungal colonization was not affected by the presence of H. glycines. The direct mechanisms by which H. glycines and M. phaseolina interact were not demonstrated in this study. Future studies must be conducted in the field and greenhouse to better understand this interaction effect.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Glycine max
/
Tylenchoidea
Tipo de estudo:
Prognostic_studies
Limite:
Animals
País/Região como assunto:
America do norte
Idioma:
En
Revista:
Phytopathology
Assunto da revista:
BOTANICA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Paraguai
País de publicação:
Estados Unidos