<![CDATA[Abstract. Nguyen VL, Nguyen XH, Dang XC, Truong TTN, Ho VT. 2026. Field-based assessment of rhizosphere bacterial communities in banana and Goeppertia allouia in response to a banana fiber-derived bioproduct. Nusantara Bioscience 18 (1): n180109. https://doi.org/10.13057/nusbiosci/n180109. Banana fiber processing generates substantial residual biomass that can potentially be converted into value-added agricultural inputs. This field-based study provides a comparative assessment of rhizosphere bacterial communities associated with banana (Musa spp.) and Goeppertia allouia observed under local management practices in a farmer-managed agricultural system. Utilizing three composite biological replicates per treatment, rhizosphere soil samples were collected from fertilized and unfertilized plots, and microbial communities were analyzed using 16S rRNA gene sequencing. Amplicon Sequence Variants (ASVs) were generated using the DADA2 pipeline and classified against the SILVA database. No statistically significant differences in alpha diversity were observed, although ASV richness ranged from 6,045 to 10,270 across samples. In contrast, beta diversity analysis revealed differences in microbial community composition. Bray-Curtis dissimilarity values indicated separation between the two crop species (> 80), while within-treatment variation ranged from 38.30 to 66.34. PERMANOVA analysis showed that plant species were significantly associated with variation in microbial community composition (R² = 0.41, p = 0.001), whereas fertilizer treatment showed a weaker but detectable association (p < 0.05). At the phylum level, Proteobacteria (35-45%) and Firmicutes (5-10%) were relatively more abundant in fertilized soils, while Acidobacteriota (10-15%) and Chloroflexi (12-18%) were more represented in unfertilized soils. These observed shifts reflect crop-specific and management-associated bacterial profiles, with plant species showing a stronger association than fertilizer treatment. Overall, the findings provide preliminary insights into rhizosphere microbial variation under field conditions. Given the farmer-managed design, lack of baseline soil characterization, and observational nature of the study, the results should be interpreted as indicative of community-level patterns rather than definitive evidence of treatment effects. From a practical perspective, the findings support cautious use of banana fiber-derived bioproducts as a complementary soil input, while emphasizing that crop identity and field heterogeneity must be considered when interpreting microbiome responses.]]>
