Agronomic contribution of PGPR in Argentina: evolution and perspectives. Mesa redonda 7. MC ? 012

DIAZ ZORITA, MARTIN

La Falda. Córdoba

Workshop; PGPR Latinoamérica 2014. II Latin American PGPR Workshop. II Taller Latinoamericano sobre Rizobacterias Promotoras del Desarrollo Vegetal; 2014

UNRC. Univ. Nacional de Quilmes. Univ. de Antioquía

Abundant natural processes related with plant growth have the participation of microorganisms from the rizosphere responsible for the normal functioning of the agroecosystems. Several of these processes have a direct contribution to the nutrition of the plants, for example atmospheric nitrogen fixation of rhizobia in symbiosis with legumes or organic mineralization or mineral solubilization of fungi or bacteria increasing the availability of certain nutrients. Other microorganisms promote the root development having an indirect or derivate effect on the enhancement of plant growth and productivity. Certain microorganisms from the rizhosphere contribute to the health of the plants controlling them against pest and diseases. The studies and extensive experiences showing the benefits of the inoculation with rizosphere microorganism on crop growth are abundant. The purpose of this presentation is to expose and to discuss about several of the contributions of the inoculation with selected plant growth promoter?s microorganisms to the growth and productivity of extensive crops in Argentina. The seed application of formulations containing Azospirillum brasilense in wheat (Trititucm aestivum) or corn (Zea mays), among other crops, showed enhancement in the early growth of the crops (more shoot and root biomass production) with more grain yields. From the evaluation of 550 wheat field trials and 279 field trials with corn, the mean grain yield response over the control was 6 % and the benefits were observed in more than 72% of the sites. Azospirillum brasilense in combination with Sinorhizobium meliloti showed benefits in the establishment of alfalfa (Medicago sativa) pastures supporting the incorporation in the industrial seed treatment process. Pseudomonas sp. and Penicillium bilaiae are other microorganisms from the rizosphere included in several inoculants because of their contribution enhancing the availability and plant uptake of nutrients. In the case of the inoculation of soybean (Glycine max (L.) Merrill) seeds with Penicillium bilaiae, the field evaluation of 106 sites showed, independently of the phosphorus fertilization strategy, a better roots growth, 8 % mean increase in grain yields and a greater consistence in the response to Bradyrhizobium japonicum inoculation. The crop results to the inoculation with rhizobia, mainly supported for the direct effect on nitrogen nutrition of legumes, support the growth and the sustainment use inoculants for their production among disperse environmental conditions. In the case of inoculants containing plant growth promoters, although their benefits to mitigate abiotic stresses providing multiple benefits for crop production, their use in the current production programs is limited. Among others, the current challenge for their development is relevant to intensify its valorization under regular production conditions as well as its communication integrated to sustainable crop management programs. CONFERENCIA