What Goes Into Breeding at GTR?

Welcome to GTR Seeds. Glad you found us.

We're not pollen chuckers, we're not hype breeders selling overpriced seeds at conventions, and we spend virtually nothing on traditional advertising.

We're an independently owned, plant-first cannabis breeding company that combines decades of growing experience with modern science to develop some of the most unique, consistent, and productive feminized cannabis genetics available.

No outside investors, no stock offerings, and no shortcuts. Our breeding program has been built and funded through our own innovations.

From purpose-built seed production facilities and cutting-edge genomic research to thousands of plants that never make the cut, an enormous amount of work goes into every variety we release.

Here's a look behind the scenes.

From Oregon CBD to GTR Seeds

Our roots in cannabis go back to the Oregon Medical Marijuana Program.

In 2006, after our co-owner Seth Crawford suffered a herniated disc, he suddenly had plenty of time to tinker with cannabis plants. The breeding began, and his brother Eric Crawford soon joined the effort while studying horticulture at Oregon State University.

The epitome of closet growers. But they grew.

Years of breeding, research, and mountains of data eventually led to the creation of Oregon CBD in 2015.

Oregon CBD became a pioneering force in cannabinoid breeding, developing varieties that helped establish the modern CBD and CBG hemp industries.

But we never saw cannabis as two separate plants.

Whether a variety produces THC, CBD, CBG, THCV, or another cannabinoid, it's all Cannabis sativa L.

GTR Seeds was created to bring our breeding innovations to the broader cannabis market, including high-THC genetics, novel cannabinoids, and our industry-leading triploid breeding program.

True F1 Hybrid Cannabis Seeds: Years in the Making

One of the biggest differences between our breeding program and conventional cannabis seed production is our focus on true F1 hybrids.

Many cannabis breeders select two plants they like, cross them, and release the resulting seeds. Sometimes that produces something fantastic, but the offspring can also vary tremendously in growth, maturity, cannabinoid content, and flower quality.

We take a different approach.

Our breeding process begins by selecting plants with desirable traits, whether that's exceptional flower production, a unique cannabinoid profile, early maturity, disease resistance, or incredible aromas.

We then spend multiple generations inbreeding, testing, selecting, and eliminating plants that don't meet our standards.

Every generation involves growing large populations, taking cuttings, collecting data, and discarding the overwhelming majority of plants.

We repeat the process with a second parental line until we've developed two carefully selected, relatively uniform parents.

Only then do we make the final cross.

The resulting F1 hybrid seeds combine the genetics of two distinct parental lines, producing plants with predictable characteristics and the potential for exceptional hybrid vigor.

The goal isn't simply to create a beautiful individual plant. It's to produce thousands of plants that perform consistently.

For commercial growers, that uniformity can make an enormous difference in crop management, harvest timing, and profitability.

Want to dig deeper? Read our guide to true F1 hybrid cannabis seeds.

Early-Maturing Cannabis Genetics

Another hallmark of our breeding program is our focus on early maturity.

Many of our photoperiod varieties incorporate day-neutral genetics in their breeding history, allowing plants to initiate flowering earlier in the outdoor season while remaining photoperiod sensitive.

This can provide an enormous advantage for growers in regions where autumn rainfall, cold temperatures, and disease pressure threaten late-season harvests.

Here in Southern Oregon, many of our varieties finish in September, well before traditional late-maturing cannabis cultivars.

Earlier harvests can mean fewer problems with autumn weather, less disease pressure, and a much more manageable growing season.

And nobody particularly enjoys harvesting cannabis in a November snowstorm.

How We Produce Feminized Cannabis Seeds

Every seed we sell is feminized.

To produce feminized seeds, we use a controlled process involving silver thiosulfate (STS), which induces genetically female plants to develop pollen-producing male flowers.

That pollen is used to fertilize carefully selected female plants, producing seeds expected to develop predominantly into female plants.

It's a relatively straightforward concept, but producing large quantities of high-quality feminized seeds requires considerable planning, labor, and precision.

Some parental lines produce abundant pollen, while others produce very little. Timing, environmental conditions, and the reproductive characteristics of each line all influence seed production.

We also spend years evaluating our genetics for stable sex expression, eliminating breeding candidates that demonstrate undesirable tendencies toward hermaphroditism.

In our own growing experience, we generally observe approximately one phenotypically male plant for every 4,000 plants grown from our feminized seeds.

Feminization dramatically reduces the likelihood of male plants, but it doesn't eliminate every possible sex-expression abnormality.

Our Oregon Cannabis Seed Production Facilities

All of our seeds are produced in our own facilities here in Oregon. We don't outsource seed production.

Our operation includes 18 purpose-built greenhouses equipped with climate control, supplemental lighting, heating, cooling, dehumidification, and systems designed to minimize unwanted pollen cont

amination.

We also maintain more than two acres of solar panels to help offset the substantial energy requirements of our operation.

Producing feminized cannabis seeds requires carefully controlled pollination.

Unwanted pollen from a neighboring cannabis crop can compromise an entire seed production run. When you're producing seeds with specific cannabinoid profiles and carefully developed parental genetics, contamination simply isn't acceptable.

Maintaining control over our seed production allows us to protect genetic identity, monitor quality, and ensure that the seeds growers receive are the varieties they ordered.

Cannabinoid Testing: We Don't Guess

Cannabis breeding becomes considerably more complicated when you're working with different cannabinoid types.

A plant producing high levels of CBD may look nearly identical to one producing THC, CBG, or THCV.

You can't reliably identify cannabinoid content by looking at a flower.

That's why analytical testing is such an important part of our breeding program.

We invested in high-performance liquid chromatography (HPLC) equipment to analyze cannabinoid production throughout the selection process.

This allows us to identify plants expressing desirable cannabinoid profiles, track inheritance across generations, and eliminate unsuitable breeding candidates.

When you're developing seeds for commercial hemp farmers, getting the cannabinoid profile wrong can have serious financial and regulatory consequences.

Testing isn't an optional extra. It's fundamental to responsible cannabis breeding.

Breeding with Science 

Genomics and Cannabis Research

Our breeding program goes far beyond growing plants and evaluating flowers.

We've invested heavily in genomic sequencing, genetic mapping, and laboratory equipment to better understand the biology of cannabis.

Our research capabilities include PacBio Sequel II long-read sequencing technology, flow cytometry, and extensive cannabinoid analysis.

These tools allow us to investigate genetic variation, identify useful molecular markers, and measure chromosome numbers in our breeding populations.

Our team has also contributed to numerous scientific publications, including a landmark 2025 cannabis pangenome study published in Nature.

That research analyzed 193 cannabis genomes and provided important new insights into cannabinoid synthase genes, genetic diversity, and cannabis domestication.

We're proud to contribute to publicly available research that helps advance cannabis science for everyone.

Explore our scientific publications and affiliated research.

Our genetics have also been evaluated in independent field trials at universities across the United States, including Cornell University, the University of Vermont, North Carolina State University, and others.

Explore university research featuring GTR Seeds and Oregon CBD genetics.

Triploid Cannabis Seeds: Our Most Ambitious Breeding Project

Of all the projects we've undertaken, developing commercial triploid cannabis seeds has been among the most challenging.

Conventional cannabis plants are diploids, meaning they contain two sets of chromosomes. Triploid plants contain three.

This unusual chromosome arrangement greatly reduces fertility, making triploids much less likely to produce seeds when exposed to pollen.

For growers producing premium seedless flowers, that's an enormous advantage.

But producing triploid seeds is anything but simple.

First, we develop carefully selected parental lines through years of inbreeding and testing.

Next, we induce chromosome doubling in one of the parents to create a tetraploid plant containing four sets of chromosomes.

This is a difficult process. Many treated plants don't survive, and others develop a mixture of diploid and tetraploid tissues.

Using flow cytometry, we repeatedly test developing shoots to identify and maintain stable tetraploid material.

Once we've established suitable parental plants, we propagate them and begin the challenging process of producing triploid seeds.

Tetraploid plants are often considerably less fertile than conventional diploids, and our triploid seed production runs may yield only 5–30% as many seeds as comparable diploid crosses.

All while requiring substantially more labor, testing, and resources.

The result is feminized F1 hybrid triploid cannabis seeds with greatly reduced fertility and, in many of our varieties, exceptional flower quality and production.

It's a tremendous amount of work, but we believe the results speak for themselves.

Learn more about triploid cannabis seeds.

Breeding for Rare Cannabinoids: CBG, CBDV, THCV, and CBGV

THC and CBD may be the best-known cannabinoids, but cannabis produces a remarkable diversity of compounds.

We've spent years developing genetics rich in less common cannabinoids, including CBG, CBDV, THCV, and CBGV.

Breeding these varieties can be incredibly challenging.

Rare cannabinoid traits may involve complex inheritance patterns, unusual synthase genetics, and combinations of alleles that require extensive testing and selection to identify.

Finding a single plant with an interesting cannabinoid profile is one thing. Developing consistent, feminized F1 hybrid seeds that reliably express that profile is another challenge entirely.

Our process often involves growing thousands of plants, analyzing cannabinoid content, developing parental lines, and repeating the process over multiple generations.

It's expensive, time-consuming work, and not every project results in a commercial release.

But we're fascinated by the potential of these cannabinoids and excited to make them more accessible to growers and researchers.

Certified Organic Cannabis Seeds

We're also proud of our work producing USDA-certified organic cannabis seeds.

Organic seed production requires additional oversight, documentation, and adherence to applicable organic production standards.

For growers pursuing certified organic cultivation, access to organically produced seed can be an important consideration.

Our breeding program relies on conventional plant breeding and selection methods rather than genetic engineering.

Why We Put So Much Work Into a Seed

We've always believed that great cannabis genetics are built through years of selection, testing, and experience.

Anyone can cross two plants and make seeds. Developing consistent, vigorous, reliable genetics that perform across thousands of acres is an entirely different challenge.

From the first breeding selections to the final seed harvest, our process involves an enormous amount of work that most growers will never see.

And that's exactly how it should be.

When you plant 10 seeds or 100,000, our goal is the same: provide genetics you can count on.

Thanks for taking a look behind the scenes at GTR Seeds. We know you'll appreciate the work.

Explore our complete lineup of feminized cannabis seeds.