News: Genetic Mapping of Cannabis Reveals Four Distinct Lineages and Offers Breakthrough in Early Sex Identification.
- Manuel Basegla
- Aug 15
- 2 min read
Published 12:00 AM EST, Fri Aug 15, 2025
Researchers at the Institute of Plant Breeding and Genetic Resources in Thessaloniki, Greece, examined 83 cannabis genotypes using a combination of 10 microsatellite markers and high-resolution melting (HRM) analysis. The plants represented a wide range of chemotypes — from low-THC fiber hemp to THC-rich marijuana — and were preserved in a germplasm collection for breeding purposes.
A new study from the Institute of Plant Breeding and Genetic Resources in Greece has mapped the genetic diversity of Cannabis sativa in unprecedented detail, revealing four distinct genetic lineages. Using 83 genotypes from both low-THC hemp and high-THC marijuana, researchers combined microsatellite markers with high-resolution melting (HRM) analysis. The results showed that cannabis genetic structure is far more complex than the traditional “hemp versus marijuana” division, with clusters shaped by breeding history and geographic origin as much as by cannabinoid profile.
The study identified a European fiber hemp group with high CBD or CBG and low THC, a marijuana group bred for potency, a hybrid group with mixed ancestry, and a genetically distinct second hemp lineage. Hemp displayed greater allelic diversity and unique genetic markers compared to marijuana, reflecting its broader selection history for fiber, grain, and oil. Importantly, most genetic variation existed within individual plants rather than between hemp and marijuana categories, underscoring the limitations of simplistic classifications.
Alongside mapping diversity, the team validated a rapid HRM-based DNA test to determine plant sex early in growth. This method correctly identified male and female plants long before flowering, allowing growers to avoid unwanted pollination. While unable to detect late-developing hermaphroditism, the approach is inexpensive, accurate, and much faster than traditional visual inspection, offering a significant advantage for cultivation planning.
This research provides a deeper genetic framework that could transform breeding, conservation, and commercial production. By moving beyond THC content as the main differentiator, breeders can tap into underutilized genetic diversity to create more resilient, high-yield, and specialized cultivars. The HRM sex test offers direct operational benefits, reducing wasted space, resources, and labor on unwanted male plants, which is crucial for both large-scale producers and small craft growers. Ultimately, these findings could help the cannabis industry transition toward more scientifically informed, data-driven cultivation strategies, improving both product quality and economic efficiency.
Source: The Marijuana Herald
