Resposta de cultivares de trigo à inoculação com Methylobacterium symbioticum sob diferentes doses de adubação nitrogenada

Abstract

The study evaluated the response of the inoculation of the bacterium Methylobacterium symbioticum in the nitrogen fertilization of two wheat cultivars (TBIO Calibre and TBIO Trunfo), aiming to verify the potential enhancement in vegetative development and, consequently, in productivity. The experiment was carried out in Marmeleiro-PR, in a randomized block design with six fertilization treatments (control, nitrogen fertilization in two doses, bacterium alone, and combinations of bacterium + nitrogen). The evaluated variables included plant height, number of tillers, chlorophyll content, thousand-grain weight, leaf biomass, leaf NPK contents, number of spikelets, grains per spike, thousand-grain weight, and yield. The inoculation was performed aerially at a rate of 333 g ha−1 (concentration of 3 × 107 CFU), five days before the urea topdressing, favoring the plant-bacterium interaction. Statistical analyses were conducted using GENES software, applying ANOVA and Duncan’s test at 5% probability, in addition to Pearson’s correlation. The results showed that the inoculation with M. symbioticum, especially when associated with 80 kg ha−1 N, significantly increased the number of spikes per plant, chlorophyll B content, and leaf nitrogen concentration, mainly in the TBIO Trunfo cultivar. On the other hand, TBIO Calibre stood out for its higher thousand-grain weight and overall productivity. Correlation analyses evidenced positive associations among yield, plant height, tillering, and leaf nutrient contents, as well as an inverse relationship between the number of spikes and thousand-grain weight. It is concluded that the use of M. symbioticum is a promising strategy for the sustainable management of wheat, mainly regarding vegetative parameters, although it did not show a significant effect on total productivity. However, the results still require validation under different environmental and genetic conditions.