Growth and yield response of canola to bacterial inoculants: a three-year field assessment
de Freitas, J.R.
Nine rhizobacteria able to produce auxins (IAA-like substances) in vitro were assessed for the ability to promote growth of canola (Brussica napus L., cv. Legend) in a growth chamber. Strains that exhibited plant growth promotion activity in this screening were then tested as seed inoculants for canola at multiple field sites (n=3 or 4; 16 reps.) in Saskatchewan over a three-year period. Plant growth and yield response varied from site to site and year to year. For example, in the 1993 study Bacillus strain HPR3 increased (P<0.05) seed yield by 104 to 158 kgeha-1 (8-18%) at two of the four sites, but had no effect at the other sites. In the 1994 study, Xunthomonas strain HPR2, strain HPR3 and Arthrobucter strain HPR9 increased (P<0.05) canola seed yield by 90 to 109 kgha-1 (7%) at the Melfort site only. In the 1995 study, strain HPR9 increased (non-significant) seed yield by 140 kgha-1 (12%) at the Melfort site. Non-significant seed yield increases (45- 90 kg-ha-l; 5-8%) also were noted for other strains at other sites. None of the inoculants affected seed oil (%) content, seed emergence or plant height. Sometimes inoculants decreased yields at some sites. Our results demonstrate that some rhizobacteria may benefit canola growth, but edaphic and climatic conditions can influence inoculant efficacy. Furthermore, site-to-site field variability suggests that extensive field testing will be required to demonstrate the potential usefulness of rhizobacteria as biofertilizers.
The following license files are associated with this item: