Contents
Controlled Pollination Methods
Successful cannabis hybridization depends on proper pollen control to ensure genetic integrity and prevent unwanted cross-pollination.
Male Isolation Techniques
| Method | Equipment | Best For | Considerations |
|---|
| Separate Room | Isolated grow space with negative pressure | Commercial breeding | Most secure but requires dedicated space |
| Isolation Chamber | Tent or cabinet with filtered exhaust | Small-scale breeding | Effective with proper protocols |
| Greenhouse Section | Physical barriers, separate ventilation | Multiple breeding projects | Requires careful management |
| Pollination Bags | Non-woven fabric or paper bags | Individual branch pollination | Economical, allows multiple crosses on one plant |
Female Preparation
| Stage | Visual Indicators | Optimal for Pollination | Notes |
|---|
| Early flowering | First white pistils visible | Too early | Poor seed set |
| Mid flowering | 50-75% of pistils white and extended | Ideal timing | Maximum receptivity |
| Late flowering | Pistils darkening, retracting | Less effective | Reduced seed set |
| Very late | Most pistils brown/orange | Poor results | Few viable seeds |
Pollen Collection & Storage
Collection Methods
| Method | Procedure | Advantages | Disadvantages |
|---|
| Direct Tap | Gently tap mature flowers over clean surface | Simple, immediate use | Less efficient collection |
| Paper Bag | Place bag over maturing flowers for 1-2 days | Easy, collects most pollen | May include flower debris |
| Screen Method | Sift flowers through fine mesh screen | Cleaner pollen sample | More labor intensive |
| Vacuum Collection | Use modified vacuum with filter | Most efficient for large scale | Requires specialized equipment |
Processing & Storage
| Step | Materials | Protocol | Notes |
|---|
| Drying | Silica gel packets | Place collected pollen in paper envelope with desiccant for 24-48 hours | Critical step, removes moisture |
| Screening | Fine mesh screen (100-200μm) | Gently sift dried pollen to remove debris | Improves purity and viability |
| Packaging | Paper coin envelopes, small glass vials | Place 0.1-0.5g portions in separate containers | Prevents repeated thawing of main stock |
| Storage | Freezer (-20°C) | Add desiccant packet to container before freezing | Label clearly with date and male source |
Pollen Viability
| Storage Method | Expected Viability | Testing Method |
|---|
| Room temperature | 1-3 days | Apply to female flower, check seed formation |
| Refrigerator (4°C) | 1-3 weeks | Fluorescein diacetate staining, 0.5% solution |
| Freezer (-20°C) with desiccant | 6-12 months | Germination on 5% sucrose agar, count germinated grains |
| Ultra-cold (-80°C) | 1-2+ years | In vitro germination, specialized equipment |
Hybridization Techniques
Standard Pollination Methods
| Technique | Application | Procedure | Considerations |
|---|
| Whole Plant | Seed production | Apply pollen to entire female plant | Maximum seed yield but uses more pollen |
| Branch Selection | Multiple crosses | Apply pollen to labeled branches | Allows multiple fathers on one mother |
| Limited Bud Sites | Test crosses | Apply pollen to specific lower buds | Economical for testing multiple males |
| Isolation Bag | Precise control | Cover branch with pollen inside breathable bag | Prevents unwanted pollination |
Diluting Pollen for Application
| Carrier | Ratio (Pollen:Carrier) | Application Method | Notes |
|---|
| Flour | 1:20 - 1:50 | Soft brush or shaker | Most common, inexpensive |
| Talc | 1:20 - 1:50 | Soft brush or shaker | Flows well, inert material |
| None | Pure pollen | Watercolor brush | For controlled, precise work |
| Tool | Best For | Technique |
|---|
| Small paintbrush | Precise application | Dip in pollen, gently brush on pistils |
| Cotton swab | Single bud pollination | Twist swab with pollen among pistils |
| Squeeze bulb | Multiple plants | Puff air to distribute pollen cloud |
| Modified electric toothbrush | Commercial scale | Vibration helps pollen distribution |
Seed Harvesting & Processing
Maturation Timeline
| Weeks After Pollination | Visual Indicators | Seed Development Stage |
|---|
| 1-2 weeks | Pistils recede, calyx swells | Embryo forming |
| 3-4 weeks | Seeds light green/white | Seed filling, immature |
| 5-6 weeks | Seeds tiger-striped or dark | Optimal maturity |
| 7+ weeks | Seeds may drop from calyx | Fully mature, may self-disperse |
Harvesting Methods
| Scale | Method | Equipment | Notes |
|---|
| Small-scale | Hand separation | Tweezers, small scissors | Labor intensive but gentle |
| Medium-scale | Screen separation | Stacked screens of decreasing sizes | Efficient for moderate quantities |
| Large-scale | Mechanical separation | Seed separator/thresher | Fastest but may damage seeds |
Seed Cleaning Protocol
- Initial Separation: Remove seeds from plant material using appropriate method for scale
- Dry Sifting: Pass through stacked screens (#10 → #20 → #40) to separate by size
- Winnowing: Use gentle air current to separate lightweight chaff
- Final Cleaning: Manually remove any remaining debris
- Drying: 24-48 hours in paper envelope at ~20°C, 40-50% humidity
Seed Storage
| Method | Temperature | Humidity | Container | Expected Viability |
|---|
| Short-term (1 year) | Cool room temp (15-20°C) | 20-30% | Paper envelopes | 80-90% |
| Medium-term (2-5 years) | Refrigerator (4°C) | <20% | Airtight glass jars with desiccant | 70-80% |
| Long-term (5+ years) | Freezer (-20°C) | <10% | Vacuum-sealed bags with desiccant | 50-70% |
Record Keeping System
Essential Documentation
| Information | Format | Purpose |
|---|
| Parent Information | Pedigree chart | Tracks genetic lineage |
| Cross Date & Method | Breeding log | Documents hybridization details |
| Environmental Conditions | Growth records | Important for repeatability |
| Seed Yield & Quality | Harvest records | Evaluates cross effectiveness |
| Phenotypic Notes | Standardized scoresheets | Selection criteria for next generation |
Sample Labeling System
[Project]-[Generation]-[Mother ID]×[Father ID]-[Date]
Example: CBD-F1-WH6×BL4-20250429
- Project: Research goal or product line
- Generation: F1, F2, BC1, etc.
- Mother ID: Female plant identifier
- Father ID: Male/pollen donor identifier
- Date: Pollination date (YYYYMMDD)
Digital Record Template
| Field | Example | Notes |
|---|
| Cross ID | CBD-F1-WH6×BL4 | Unique identifier |
| Mother traits | High CBD (18%), WH phenotype, early finish | Key selection criteria |
| Father traits | Terpene profile (myrcene dominant), mold resistance | Key selection criteria |
| Pollination date | 2025-04-29 | Calendar date |
| Seed harvest date | 2025-06-10 | Calendar date |
| Seed quantity | 342 seeds | Total count or estimate |
| Storage location | Freezer B, Drawer 3, Vial 28 | Precise location |
| Breeding objectives | CBD:THC ratio, disease resistance | Goal of cross |
| Notes | Mother showed light stress week 4, father had vigorous pollen production | Relevant observations |
Tip: Create a breeding database that links parent selection criteria, crossing data, and progeny evaluation to track traits across generations and improve selection efficiency.
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