Growth promoters in banana seedlings submitted to saline irrigation

The objective of this study was to evaluate the effect of inoculation of a plant growth promoter bacteria on the growth of micropropagated banana seedlings cultivar Williams under irrigation with water at different saline levels. The experiment was carried out in a greenhouse at Embrapa Agroindústria Tropical, Fortaleza, State of Ceará. The experimental design was in randomized blocks, in a 3 x 4 factorial scheme, corresponding to the three factors for growth promotion (negative control: water; Osmocote® slow-release fertilizer and a Bacillus spp. bacterium) subjected to four levels of irrigation water salinity (S1 = 0.5; S2 = 1.5; S3 = 3.0 and S4 = 4.5 dS m-1), and five blocks, totaling 60 experimental units. Sixty days after transplanting (DAT) and application of treatments, the following variables related to plant growth were measured: number of leaves (NL), pseudostem diameter (PD), plant height (PH), leaf area (LA), and root length (RL). The rise in saline levels in the irrigation water negatively influenced the variables number of leaves, pseudostem diameter, root length, and leaf area, showing a decreasing linear behavior. The variables number of leaves and leaf area of seedlings inoculated in association with Bacillus spp. did not differ from each other, regardless of the saline level. This indicated a likely increase in the response to the salinity tolerance of the seedlings. Treatment with Osmocote® fertilizer differed statistically for variables plant height, pseudostem diameter, and leaf area.