Researchers at the University of Florida’s Institute of Food and Agricultural Sciences are advancing toward a breakthrough that could significantly protect the U.S. lettuce supply, developing new varieties resistant to bacterial leaf spot while also addressing rising temperature pressures on the crop.
Backed by a $500,000 grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture, the research is led by Germán Sandoya, an associate professor of horticultural sciences. The effort focuses on tackling bacterial leaf spot, a persistent disease that reduces yield and quality and currently has no effective chemical control options for growers.
To develop resistance, scientists incorporated genetic material from a wild lettuce plant originally collected in Macedonia. While not suitable for commercial use on its own, the plant has served as a critical genetic source, enabling researchers to create hundreds of advanced breeding lines across multiple lettuce types, including romaine, iceberg, and leaf varieties.
The program has now entered large-scale validation, with trials planned across Florida, California, and Arizona to evaluate performance under diverse climates, production systems, and soil conditions, including sandy soils common in Florida. Researchers are also testing the lines in greenhouse environments to assess consistency and scalability.
In addition to disease resistance, the breeding program is focused on meeting commercial requirements such as appearance, texture, storage life, and long-distance transport durability. These traits are essential for ensuring that new varieties meet the needs of growers, retailers, and consumers.
Early findings suggest the resistance traits may also extend to Cercospora leaf spot, another disease that becomes more prevalent in warm conditions and lacks effective control options, particularly in greenhouse production. If confirmed, the development could result in one of the first public lettuce cultivars with resistance to multiple major diseases.
Once top-performing lines are identified, the team plans to scale seed production, prepare varieties for mechanical planting, and conduct field demonstrations to accelerate adoption among growers and industry stakeholders. Researchers indicate the timeline for commercial availability could be shorter than traditional breeding cycles, depending on seed scale-up and market acceptance.
KEY QUOTES:
“This type of research takes time. From the earliest breeding stages to releasing a cultivar, you are looking at seven to eight years. But we are now at the point where we have multiple promising lines and are narrowing them down.”
Germán Sandoya, Associate Professor Of Horticultural Sciences, UF/IFAS
“We have developed a wide range of lettuce types, including romaine, iceberg and leaf lettuce. The goal is to provide growers with options that perform well in different production systems and meet market demands.”
“Our goal is to deliver solutions that work for growers in the field and provide high quality produce for consumers. We are getting very close.”
Germán Sandoya, Associate Professor Of Horticultural Sciences, UF/IFAS
