Morphological and Biochemical Characterization of Soybean Nodulating Rhizobia Indigenous to Zambia
Bibliographic record
Abstract
Soybean [Glycine max (L.) Merrill] is known for nitrogen fixation by rhizobia present in the soil with which it establishes an efficient symbiosis. In Zambia, current rhizobial inoculants used in soybeans production are based on non-indigenous strains; this creates a need to isolate local strains that can be used for the development of local inoculants for soybeans in Zambian soils. This paper reports the isolation and characterization of rhizobial isolates from virgin and cultivated soils of the three agro-ecological regions of Zambia. Rhizobia were isolated using the Trap Method and characterized using selected morphological and biochemical markers. A total of 61 isolates were isolated on Yeast Extract Mannitol (YEM) agar medium. Isolates varied in colony form, color, margin and texture. From the 61 isolates from the three regions, 87 % were circular, 8 % irregular and 5 % punctuate in form with 100 % convex elevation. The isolates had 88% entire, 10% undulate and 2 % lobate colony margins with different colors – 56 % cream, 24 % white, 11 % yellow, 5 % transparent and 3 % pink. Transparent colonies were peculiar to Region I and III while pink colonies were peculiar to Region III. All isolates produced mucous, were gram negative and rod shaped, a characteristic of rhizobial cells. None of the isolates could tolerate extremes of pH (4 and 9) in growth medium but grew well at pH 6.8. All isolates utilized glucose as a source of carbon. Based on the Bromothymol Blue (BTB) assay, 59 isolates were fast growing while two isolates from cultivated soils of region II were slow growing. The fast growing 59 isolates showed an acidic reaction changing the medium from green to yellow, while the others showed an alkaline reaction. Based on the results, the 59 fast-growers could be Ensifer fredii or/and Rhizobium tropici rather than Bradyrhizobium. However, further tests to confirm these findings using ketolactose, genetic characterization and inclusion of reference strains, are still needed and are being recommended here.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".