Efficacy of Cladosporium cladosporioides C24G as a Multifunctional Agent in Upland Rice in Agroecological Systems

Abstract

The occurrence of diseases in rice, mainly rice blast (Magnaporthe oryzae), is the main cause of yield reduction, and it has been controlled with the abusive use of fungicides in the conventional production system. To produce rice in an agroecological system, some measures, such as biological control, facilitates the transition from one system to another. The biological agent C24G classified as Cladosporium cladosporioides has been isolated from the phylloplane of rice plants and is a potential antagonist to rice pathogens. The aim of this study was to verify the efficiency of C. cladosporioides C24G under field conditions, in an agroecological system. During two growing seasons, C. cladosporioides was tested in a randomized block design in 4 replicates. The treatments consisted of: microbiolized rice seeds with C. cladosporioides, plant sprayed (2 applications), microbiolized rice seeds with C. cladosporioides + plant sprayed (2 ap.), plant sprayed (8 ap.) and microbiolized rice seeds with C. cladosporioides + plant sprayed (8 ap.) and control (no microbiolization and no spray). We evaluated leaf and panicle blast severity, physiological parameters associated with gas exchange, and grain yield. Leaf and panicle blast suppression was up to 85.58% and 79.63% in growing season 2016/2017, respectively, and 83.06% and 74.98% in growing season 2017/2018. At growing season 2016/2017, we observed an increase of the following parameters: photosynthetic rate (A) of 70.99% and 53.52% and transpiration (E) of 22.98% and 59.73% at vegetative and reproductive stage respectively, stomatal conductance (gs) of 126.66% at reproductive stage, water use efficiency (WUE) was up to 55.29% at vegetative stage, biomass 34.56% and yield 51.30%. At the growing season 2017/2018, we observed an increase at the photosynthetic rate (A) of 29.71%, at reproductive stage, biomass, 89.40%, and yield, 34.19%. We conclude that the treatments, microbiolized rice seeds or plant sprayed, allows the insertion of C. cladosporioides into the agroecological system, facilitating the agroecological transition with considerable grain yield, and leading to a final product without residues.