EVALUATION OF WATER STRESS AND CO-INOCULATION OF AZOSPIRILLUM BRASILENSE AND RHIZOBIUM TROPICI IN BEANS (PHASEOLUS VULGARIS L.)

Climate change has caused major changes in abiotic factors, with water stress as the greatest threat to agricultural production. The measures aimed at alleviating the problems caused by this limiting production factor have occurred through the adoption of sustainable strategies, especially microbial biotechnology, which uses the interactions between the microorganism and the plant, ensuring productive quality and inducing plant resistance to stresses biotic and abiotic. The objective of the present work was to evaluate the biological nitrogen fixation and the development of bean seedlings, with co-inoculation of two types of inoculants, which were subjected to water stress by different pot capacities. The experiment was conducted in a greenhouse, at Universidade Paranaense - UNIPAR, from April to June 2019. The experimental design was completely randomized (DIC), with 5 replications, 16 treatments and 80 experimental units. The cultivar used was SCS Riqueza. The parameters evaluated were pot capacity (25%, 50%, 75% and 90%); small, large and total nodules, shoot and root length, dry and fresh weight, total carbon and nitrogen. The evaluation of the morphological parameters of the bean seedlings indicated that the co-inoculation technique promoted beneficial effects for the dry mass parameters of shoot, nodule and root. The analysis of the percentage of carbon and nitrogen in the tissues of the seedlings provided an increase in the concentration of these elements in treatments that involved co-inoculation (Azospirillum brasilensis and Rhizobium tropici) with pot capacities of 25 and 75% (CV), demonstrating that the association of microorganisms is beneficial in the limiting water situation.