You invest several months’ worth of time, money and labor into nurturing a cannabis plant from a seed—only to discover that it’s a male. It’s a frustrating scenario for any grower.
Scientists are harnessing the power of DNA to make this disappointment a thing of the past. DNA tests can help identify the sex of your plants early in the growing process, allowing you to cull males from your grow and save valuable time and grow space. Several companies offer these services to professional growers.
Phylos Bioscience, an agricultural genomics company based in Portland, Ore., offers a test that can determine a plant’s sex within seven days of germination. The grower takes a DNA sample from the cotyledon—the first two leaves to appear on the plant—by pressing the leaf onto a special filter paper and then scraping away any excess plant material. The paper has a complex of salts dried on it that helps stabilize the DNA, said Jessica Kristof, Director of Research for Phylos Bioscience. Then, the grower mails the sample in.
“They’re not sending us plant material, and the cotyledons don’t have any THC on them, so they’re not sending any illicit cannabinoids in the mail,” she said. “But they are sending DNA, which is all we need to do the test.”
Once the lab receives the sample, the DNA is extracted and tested. The test looks for two genes: the male gene and a cannabis marker gene, which ensures the sample is from a cannabis plant. This gene also serves as a control. “If the cannabis gene comes up but the male gene doesn’t, then you have a female,” Kristof said.
Phylos Bioscience guarantees results within 48 hours for orders of fewer than 1,000 samples. For larger orders, the company will work with growers to create a custom timeline, she said.
In the old-fashioned method of identifying a plant’s sex, growers must usually wait two to three months to determine if a plant is male or female. By that point, the plant is fairly large, and it’s taken an investment of soil, lighting, labor and other resources to grow it. “But this test that we’ve made allows you to just sex the plants within their seeding trays,” Kristof said.
“It’s a huge money saver,” she said, adding, “For the smaller grow size as well as the large grow size, it’s very cost-effective.”
Meanwhile, a Salt Lake City-based company gives growers a more do-it-yourself approach. SimpleGenetix offers a DNA-based test that cultivators can complete themselves on-site, said President and Chief Technologist Wesley Lang.
The company is just coming to market with the test, dubbed the Gene Genie, which growers can use to test their plants within the first two weeks of growth, said Chief Marketing Officer Caroline Bruderer.
Growers put a leaf sample into a cartridge, which contains all the chemistry needed to break open plant cells and amplify the DNA inside them, Lang said. The second phase of the process involves a device called a Thermal Cycler, which completes another crucial step in the procedure. The whole process takes about an hour.
Until recently, DNA testing has “been a fairly complex process that has to be carried out by skilled technicians in a laboratory setting,” Lang said. However, the Gene Genie’s cartridges are sterile and not subject to contamination, which allows growers to conduct the test in their grows.
“They get a result right there,” he said. “They don’t have to send it to the lab.”
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