Temporal Responses of Canola (Brassica napus L.) to Methylobacterium oryzae Applications under Controlled Conditions

Background: Plant growth-promoting bacteria can influence crop establishment, but responses may depend on the timing and frequency of application. This study examined temporal responses of canola (Brassica napus L. cv. Lakritz) to Methylobacterium oryzae DSM 18207 under controlled conditions. Methods: A seven-day germination assay compared untreated and bacterially treated seeds. A separate pot experiment evaluated five regimes: an untreated control, seed treatment alone, and seed treatment followed by one, two or three foliar applications. Germination patterns, early seedling fresh and dry biomass, and eight vegetative growth and biomass traits were assessed. Results: Treated seeds showed lower early germination counts than controls, but final means were similar (71.00 and 71.33, respectively). At the early seedling stage, fresh biomass was 0.0416 g after bacterial treatment and 0.0523 g in controls; corresponding dry biomass means were 0.0032 and 0.0035 g. In the pot experiment, application regimes differed numerically across traits. The regime with three foliar applications had the highest mean plant height and shoot length, whereas dry shoot weight was numerically higher under the regimes with one or two foliar applications than under the control. However, none of the treatment differences was considered statistically significant. Conclusions: Under the tested conditions, the application regimes did not demonstrate statistically verified growth promotion. The observed patterns warrant further investigation with increased replication, consistent application procedures and measurements of bacterial establishment.