Brooks Parrish has spent the past three years studying the genetics of lantana. These plants are beautiful, but if they’re not properly contained, they can escape cultivation, invade natural and agricultural lands, displace native plants, reduce biodiversity and pose risks to animals.
Parrish graduated with his Ph.D. from the UF/IFAS College of Agricultural and Life Sciences in August 2024. Now, he has been recognized by the office of the UF/IFAS Dean for Research for having the Best Dissertation of the Year, an honor he will officially receive May 20.
“Dr. Parrish won the overall best dissertation award in UF/IFAS, which we give to only one graduate student per year,” said Rob Gilbert, UF/IFAS dean for research and executive director for academic affairs. “His dissertation provided key knowledge on both ornamental appeal and invasion biology of lantana, for example the molecular basis of lantana’s rich red flower hues. His work will contribute significantly to effective genetic sterilization of lantana for the benefit of the ornamental horticulture industry and protecting the native species.”
Parrish worked under the supervision of Zhanao Deng and Sandra Wilson, professors of environmental horticulture.
Some lantanas are invasive; others are not, and there are native lantana species in Florida.
Parrish focused his dissertation on Lantana strigocamara (or Lantana camara) — an invasive species of lantana. Using advanced molecular techniques, he analyzed the plant’s genetics to better understand what makes it invasive. Parrish hopes that this research will help develop more sterile lantana varieties.
Among other words of praise from their letter nominating Parrish, Deng and Wilson said: “(The dissertation) tackles one of the most pressing ecological challenges in Florida and beyond: balancing the economic value of ornamental plants with the urgent need to mitigate their invasiveness. His research has made important contributions to genetic sterilization and invasive species management.”
Chapters of Parrish’s dissertation have already been published in scientific journals. One focused on sequencing the genome of lantana as a major step toward preventing the plant from becoming invasive.
To address concerns about lantana escaping into the wild, Parrish tested a faster method for sterilizing the plant, so it does not develop seeds.
By crossing certain types of lantana, he created beautiful plants that are sterile, meaning they cannot reproduce and cannot escape cultivation. This sterilizing strategy is efficient and offers a way to produce safe, non-invasive lantana for gardens, similar to the already available sterile UF/IFAS lantana cultivars Bloomify™ Rose, Bloomify™ Red and Luscious® Royal Red Zone™.
“This plant is famous for its bright, beautiful flowers that decorate gardens around the world, but it’s also infamous for its tendency to spread and cause trouble in natural and agricultural ecosystems,” said Parrish, who now works as a research and development manager for David Clark, a professor of environmental horticulture on the main UF campus. “The study set out to discover the reasons behind lantana’s appeal as an ornamental plant and to understand what makes it such a successful and potentially harmful invader.”
Parrish began his research by carefully examining lantana’s DNA, which holds all the instructions for how the plant grows, looks and survives.
He created a DNA map, which enabled him to spot the genes responsible for lantana’s striking red blooms. He paid special attention to the “color genes” and to helper genes that turn on the process for making red pigments in Lantana flowers.
Understanding lantana’s invasiveness proved an equally important milestone, Parrish said. Some lantana plants create seeds with extra sets of chromosomes. This process helps the plants adapt, survive and spread into new environments.
Parrish’s research pointed to genes that are potentially associated with this ability, and he developed a tool — a molecular marker — that can help scientists track this gene in other lantana plants.
“This dissertation bridges the gap between enjoying lantana’s beauty and protecting the environment,” Parrish said. “By understanding its genetics and finding better ways to breed safe plants, the work helps growers and scientists keep landscapes colorful without threatening nature.”
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The mission of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is to develop knowledge relevant to agricultural, human and natural resources and to make that knowledge available to sustain and enhance the quality of human life. With more than a dozen research facilities, 67 county Extension offices, and award-winning students and faculty in the UF College of Agricultural and Life Sciences, UF/IFAS brings science-based solutions to the state’s agricultural and natural resources industries, and all Florida residents.
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