Service 01 · Flagship service
Phenotyping and disease-resistance assessment
Assessment of the response of genetic materials to the main forest diseases. The trials, in greenhouse, field and controlled environment, measure the severity, progress and impact of each disease on each clone.
Why phenotype
Resistance can only be assessed in the presence of the pathogen
A clone can go through years of selection for volume and wood quality without ever being exposed to the pathogen to which it is susceptible. In a clonal plantation, that genotype occupies thousands of hectares, and the loss appears only at the end of the rotation.
- Growth trial: does not reveal susceptibility. In the absence of the pathogen, resistant and susceptible clones behave the same way.
- Occurrence in the field: varies with year, region and inoculum pressure. The absence of symptoms does not indicate resistance; the clone may have escaped the disease.
- Controlled trial: reproduces the three conditions for disease (healthy host, aggressive pathogen and favorable environment) and classifies the clones by direct measurement.
Risk calculator
Risk that no clone is resistant
In Clonar's trials, the proportion of resistant clones ranges from 29% to 59%, depending on the pathogen. When phenotyping is done only at the end of the program, with few finalists, the probability that all of them are susceptible becomes relevant.
- Choose the pathogen and the number of clones that reach the disease test.
- Compare few clones at the end of the program with many clones at the start.
- With early phenotyping, susceptible clones are discarded before the investment in field trials, when discarding them costs less.
Calculation: (1 − p)n, where p = proportion of resistant clones observed in Clonar trials for the pathogen (technical presentation, 2026). Assumes independent clones; related clones tend to behave similarly, which increases the effective risk. Dots: expected value, green = resistant.
Diseases assessed
Protocol and assessed variable by disease
| Disease | Agent | Site of attack | Main variable assessed | Resistant clones in the trials |
|---|---|---|---|---|
 Ceratocystis wilt | Ceratocystis fimbriata fungus | Wood and vascular system | Lesion length in the wood (cm) and wilting | |
 Bacterial wilt | Ralstonia solanacearum bacterium | Roots and vessels | Wilt incidence and severity | |
 Shoot blight | Erwinia psidii bacterium | Shoot tips and new shoots | Shoot blight severity | |
 Calonectria leaf blight | Calonectria pteridis fungus | Leaves | Lesioned leaf area and defoliation | |
 Teratosphaeria leaf disease | Teratosphaeria nubilosa fungus | Juvenile and adult leaves | Leaf spot severity | |
 Bacterial leaf blight | Xanthomonas axonopodis bacterium | Leaves | Severity of leaf lesions | |
 Myrtle rust | Austropuccinia psidii fungus | Shoots and young leaves | Rating scale by pustule type |
Resistant clones in the trials: proportion of the total number of clones evaluated per pathogen, Clonar resistance trials (technical presentation, 2026). Green = resistant; ochre = susceptible.
Trial stages
From planning to report, in five stages
Planning
Clones, diseases, controls and experimental design are defined with the client's team.
Controls of known response in every trialStandardized plants
Healthy seedlings of the same age and size, so that the differences observed are due to the genotype.
Healthy hostInoculation
Representative isolates from the collection, with inoculum prepared and quantified for each pathogen.
Aggressive pathogenIncubation and assessment
Environment favorable to infection, and assessment with standardized scales and direct measurements.
Favorable environmentAnalysis and report
Statistical analysis, classification by clone and recommendation for the program.
Resistant · tolerant · susceptibleTechnical report
Contents of the phenotyping report
The report presents the classification of each genetic material with the data that support it, in a format that can be incorporated into the selection index.
- Comparison with controls of known resistant and susceptible response, which validate the trial.
- Technical presentation meeting with the client's breeding team.
- Confidentiality: genetic materials and results belong to the client.
Phenotyping report · structure- Trial identificationClones, disease, isolates used with origin and collection code
- Design and conditionsReplicates, controls, inoculum, recorded temperature and humidity
- Results by cloneMeans, variability and statistical analysis of the assessed variable
- ClassificationResistantTolerantSusceptible
- Photographic recordSymptoms by clone and controls, on the assessment dates
- RecommendationTechnical interpretation for the breeding program
Custom trials
Trials adjusted to the question of each program
The resistance assessment protocol is adjusted to the program stage, the planting region and the diseases of greatest importance to the company.
Isolates from the region
When the problem is localized, the pathogen is collected and isolated from the affected stand and included in the trial.
Several isolates per disease
Panels of isolates with different levels of aggressiveness, to assess resistance against the variability of the pathogen.
Multi-pathogen panel
The same batch evaluated for two or more diseases, with an integrated reading of the health of each clone.
Screening at the start of the program
Large batches evaluated at the start of the program, when discarding a clone costs little and phenotyping gives the greatest return.
Frequently asked questions
Common questions about phenotyping trials
How many clones can I evaluate in one trial?
The trial is sized in the proposal: it ranges from screening large populations at the start of the program to confirming a few finalists. The number of replicates and controls follows the batch size, so that the statistical comparison remains valid.
Do the isolates used represent my region?
The collection holds 2,234 isolates from different regions, hosts and collection years, and isolates are chosen by origin and aggressiveness. When the problem is specific to one area, the pathogen can be collected in the client's area and included in the trial.
Do greenhouse results apply to the field?
The controlled trial reproduces the three conditions for disease under high, uniform inoculum pressure, which makes it possible to separate resistant from susceptible clones in a short time. When the question requires it, field validation is included as a stage of an applied research project.
How long does a trial take?
It depends on the disease, the pathogen and the number of planned assessments. The timeline of each trial is stated in the proposal.
Do I need to send plants, or does Clonar produce them?
The arrangement is defined in the proposal, according to the genetic material and the client's logistics.
Are the results confidential?
Yes. Genetic materials and results belong to the client and are handled confidentially.
Next step
Trial proposal for clones being released or batches under screening
Indicate the disease, the number of clones and the program stage. The technical team replies within one business day with a trial proposal.
or write to comercialclonar@gmail.com