Morphological Characterization of Ugandan Isolates of Sphaceloma sp. Causing Cowpea Scab Disease
Bibliographic record
Abstract
Scab is an important fungal disease of cowpea, affecting both young and old tissues including stems, leaves and pods of susceptible cowpea genotypes, leading to significant yield losses of up to 100% under severe infections. Colony characteristics on agar media, symptomatology, phylogenetic affinity of hosts and host range have been used to justify taxonomic distinctions. The correct identification and description of a pathogen is paramount in understanding its control or developing genotypes resistant to it. This study involved the isolation and culture of the scab fungus (Sphaceloma sp.) from infected plant parts (leaves and pods) collected from farmers’ fields across major cowpea growing districts and agro-ecological zones in Uganda. The fungus was characterized using growth habit on potato dextrose agar (PDA) media, conidia features, variability in radial growth rate (mm/day) among the isolates and pathogenicity and virulence of some isolates on 20 selected cowpea genotypes with different levels of resistance. A total of 495 Sphaceloma sp. isolates comprising of 419 from infected leaves and 76 from infected pods were obtained following isolation and culture. There was a wide variation in the isolates based on the amount, nature, colour, depth and rate of mycelia growth, features of conidia and number of septations. Based on the mean incidence, severity, AUDPC and pathogenicity on the 20 genotypes, the isolates were put into three pathogenicity groups. Isolates were mostly slow growing (> 14 days to cover entire 90 mm petri dish). Genotypes NE 31 and NE 70 showed broad spectrum of resistance to the isolates and could therefore be recommended as parental lines in the cowpea breeding programme to develop cultivars with wide horizontal resistance to the scab disease.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".