Often referred to as the most expensive spice in the world, saffron has been prized for thousands of years for its vibrant color, distinctive flavor, and aromatic compounds. Extracted from the red stigmas of the saffron crocus, Crocus sativus, it takes between 70,000 and 200,000 flowers to produce just one kilogram of dried saffron threads. But its high price reflects more than demand or the small amount harvested from each plant. The biology of saffron itself also makes the crop difficult to produce at scale.
Because saffron is a sterile triploid, meaning its three sets of chromosomes make it unable to reproduce through seeds. Growers rely on vegetative propagation through underground storage structures called corms. Each corm produces a single plant during the growing season, and over time, that plant forms a limited number of daughter corms that can be replanted in future seasons. This slow cycle is the only way to produce more saffron flowers. As a result, growers must wait several seasons to accumulate sufficient planting material, creating a significant barrier to expanding saffron production.
In a recent study led by Horticultural Sciences professor, Dr. Wagner Vendrame, researchers investigated whether a technique known as cross-cutting could increase saffron propagation under controlled environmental conditions.
“Saffron is one of the most valuable spices in the market,” said Vendrame, “Everything has to be done manually to harvest the spice, so you need a large number of plants to produce a certain yield.”
Vendrame’s research focuses on plant biotechnology techniques such as micropropagation, cryopreservation, and controlled-environment production systems. The saffron project began when Ph.D. candidate Soumaya El Merzougui, the study’s first author, joined his lab. Originally from Morocco, one of the world’s major saffron-producing regions, El Merzougui brought a strong interest in studying the crop and exploring new ways to improve its propagation.
The team recognized a growing need to develop more resilient production systems. Climate variability, temperature changes, and environmental stress can all influence saffron growth and the formation of new corms in field conditions.
“We thought… with all the issues going around the world and environmental stresses related to climate, we thought it would be a good opportunity to develop a system for producing saffron plants in a sustainable manner,” explained Vendrame.
“Using micropropagation, we can do large-scale production of plants, and if you can grow them under a controlled environment, we avoid the stresses.”
Improving Propagation for Scale
The team tested whether carefully cutting saffron corms could stimulate the formation of additional shoots and daughter corms under controlled environmental conditions. The results showed that cross-cutting significantly increased the number of shoots produced from each corm, allowing a single mother corm to generate more planting material than traditional propagation methods.
For growers, this difference is significant. In conventional production, each planted corm produces only one plant, limiting how quickly saffron fields can expand. Techniques that increase the number of shoots and daughter corms could accelerate the multiplication of planting stock while maintaining the plant’s genetic consistency.
To further improve scalability, Vendrame’s lab also studies the use of temporary-immersion bioreactors, specialized systems designed to multiply plants more efficiently than traditional tissue culture methods. In conventional tissue culture, plant tissues are grown on agar, a gel that can account for up to 80% of production costs according to Vendrame.
Temporary-immersion bioreactors instead use a liquid nutrient solution that is periodically pulsed over the plant material at controlled intervals.
A computer regulates how often and how long the tissues are immersed in nutrients, while LEDs control light conditions, and, if needed, additional carbon dioxide can be introduced to further stimulate plant growth. Because the system relies on liquid media in larger containers rather than individual gel-filled vessels, it improves nutrient uptake, air exchange, and overall efficiency while requiring relatively little physical space.
Right: Two blooming saffron crocus flowers with visible red stigmas, the threads used to produce saffron spice.
“In a small room like that, we can produce thousands and thousands of plants,” explained Vendrame.
By reducing costs and space requirements, bioreactor-based propagation could make it easier for growers to produce large quantities of saffron and other high-value crops without the need for extensive greenhouse facilities.
A Spice with Growing Health Potential
Beyond agriculture, improving saffron production could also support growing scientific interest in the crop’s potential health benefits. Compounds found in saffron include crocin, safranal, and picrocrocin, and have been found to contain antioxidant and anti-inflammatory properties.
Recent clinical studies have also explored saffron’s potential role in mental health. Some research suggests that standardized saffron
extracts may help reduce symptoms of depression and anxiety, with certain trials showing effects comparable to some antidepressant medications by influencing neurotransmitters such as serotonin and dopamine.
As interest grows in the connection between diet and human health, increasing saffron production could help expand access to the crop for both culinary use and continued research into its medicinal properties.
“We developed a protocol that has been proven to work. Any tissue culture company could use the system and start producing saffron,” stated Vendrame.
As researchers at UF/IFAS continue to explore how plants can support human health, innovations in plant propagation like this help ensure this ancient crop can be produced more sustainably and expand access to saffron in the future.
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