Promotion of rice growth and productivity as a result of seed inoculation with Azospirillum brasilense

The present study refers to the results obtained in four experiments carried out in the 2015/2016 crop: Toledo/PR; Palotina/PR; Cascavel/PR; and Sao Miguel do Iguacu/PR. The objective of the present study was to evaluate the agronomic efficiency of Azospirillum brasilense (pest strains Ab-V5 and Ab-V6) in four distinct rice culture regions (Oryza sativa L.). The tests were performed to meet the requirements of the Ministry of Agriculture, Livestock and Supply regarding the registration of the product. The experiments were conducted in a randomized block design with seven treatments and four replications, totaling 28 plots each. Rice cultivar IAC 201 was used in all four experiments. At stage R7, 10 plants were collected to measure morphobiometric variables and nitrogen content in grains (N grains). The results showed that in all evaluated sites the use of liquid inoculation with A. brasilense increased rice crop development as well as productivity. Thus, inoculation of rice seeds with A. brasilense strains Ab-V5 and Ab-V6 based inoculant in the liquid formulations increased the yield and yield components of rice crop in different regions. The inoculant based on A. brasilense strains Ab-V5 and Ab-V6, using the liquid vehicle, presented higher agronomic efficiency for rice cultivation. The inoculant based on A. brasilense strains Ab-V5 and Ab-V6 using the peat medium has good agronomic efficiency similar to the standard inoculant. These results were satisfactory contributing also to the sustainability in the agriculture.\r\n\r\n\tKey words: Diazotrophic bacteria, plant growth promoting bacteria, nitrogen fertilization, seed inoculation, Oryza sativa L.