Uso de suelos supresivos como tratamiento biológico para controlar la infección de Mildiu (Peronospora variabilis Gaum.) en el cultivo de quinua (Chenopodium quinoa Willd.)

Abstract

BIOTECNOLOGÍA AGRÍCOLA, FITOPATOLOGÍA, SUELOS SUPRESIVOS, CONTROL BIOLÓGICO, ACTIVIDAD ANTIMICROBIANA, BIOINSUMOS, MILDIU, QUINUA, PERONOSPORA VARIABILIS Abstract: Quinoa (Chenopodium quinoa Willd.) cultivation faces a significant threat from downy mildew (Peronospora variabilis Gaum.), a disease capable of reducing yields by up to ninety percent, which represents a serious obstacle to food security in high-altitude regions. To address this issue, the use of suppressive soils as a biological treatment was proposed, offering an ecological and cost-effective alternative to synthetic fungicides. The research was conducted through a comparative analysis between suppressive and conducive soils, evaluating their physicochemical and microbiological characteristics, including metagenomic analysis to identify the present microbial diversity. A bio-input was developed from the suppressive soil and evaluated through in vitro tests to determine its biocontrol capacity against P. variabilis and later validated under greenhouse conditions through inoculation in quinoa plants. The results revealed that the suppressive soil exhibited a slightly more acidic pH, higher organic matter content, and significantly greater beneficial microbial diversity, conditions that favor the establishment of antagonistic microorganisms. The formulated bio-input completely inhibited the pathogen's growth in laboratory conditions, and in greenhouse trials, the treated plants achieved one hundred percent survival, in contrast with the high mortality observed in the control groups. This confirmed that the use of suppressive soils and derived bio-inputs, supported by microbiological analysis with a metagenomic approach, represents an effective, sustainable strategy aligned with the principles of ecological agriculture for the control of downy mildew in quinoa.