Allelopathic compounds reduce the growth and productivity of upland rice plants, especially in consecutive plantations.
The rhizobacteria Pseudomonas fluorescens BRM-32111 and Burkholderia pyrrocinia BRM-32113 have been recorded as
growth promoters in rice. This study was developed to understand the effect of the application of rhizobacteria on upland
rice plants in consecutive plantations. Experiments were conducted in a completely randomized design with four replications
of four treatments: rice seed inoculated with P. fluorescens BRM-32111, rice seed inoculated with B. pyrrocinia BRM-32113
(both sown on soil with rice residue), non-inoculated plants sown on soil with rice residue (control with residue (WR)), and
non-inoculated plants on soil with no residue (NR). Roots and seedling growth were adversely affected by allelopathic
compounds in control WR plants. Plants inoculated with rhizobacteria P. fluorescens BRM-32111 or B. pyrrocinia BRM-32113
induced an increase of 88% in biomass, 3% in the leaf area, 40% in length, 67% in root biomass, 21% in chlorophyll a,
53% in chlorophyll (a+b), 50% in rate of carbon assimilation (A), 227% in A/rubisco carboxylation efficiency (Ci) and 63%
in water use efficiency (WUE) compared to control WR plants. These results indicate that rhizobacteria P. fluorescens
BRM-32111 and B. pyrrocinia BRM-32113 increase the tolerance of rice plants to stress from allelochemicals. There are
possible practical agricultural applications of these results for mitigating the effects of environmental allelochemistry on
upland rice.