Phosphorus fertilization reduces the severity of charcoal rot ( Macrophomina phaseolina ) and the arbuscular mycorrhizal protection in soybean

CHIOCCHIO, VIVIANA; SPAGNOLETTI, FEDERICO N.; LAVADO, RAUL S.; LEIVA, MICAELA

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE-ZEITSCHRIFT FUR PFLANZENERNAHRUNG UND BODENKUNDE

WILEY-V C H VERLAG GMBH

Año: 2018 p. 1 - 6

1436-8730

The effects of phosphorus (P) application on the relationship between the arbuscular mycorrhizalfungus (AMF) Rhizophagus intraradices and the pathogen Macrophomina phaseolina (charcoalrot) affecting soybean (Glycine max L.) are unknown. We evaluated the effects of P on both theseverity of the pathogen and the AMF protection against the charcoal rot in soybean. We con-ducted greenhouse experiments with a randomized multifactorial design with ten replications.The treatments were: two concentrations of P as superphosphate (0 and 50 kg of P ha?1), inocu-lated and non-inoculated with the AMF R. intraradices, and infected and non-infected withM. phaseolina. Soybean was seeded in pots containing 1 kg of sterilized substrate soil : sand :perlite (7 : 3 : 2). When soybean completed pod formation (R4 phenological stage), the plantswere harvested. Plant parameters, mycorrhizal colonization, and disease severity were meas-ured. The presence of M. phaseolina negatively affected soybean biomass, but AMF inoculationimproved it. Phosphorus reduced AMF colonization but not arbuscules percentage. Moreover,both P and AMF inoculation had a negative effect on disease severity, although P also reducedmycorrhizal protection. These results suggest that phosphorus application could reduce diseaseseverity, but can simultaneously partially reduce the AMF protection against the pathogen. Theseeffects should be considered in agricultural integrated management practices of soybean.