project BUG-FREE SWEET POTATOES

David is passionate about cultivating his Asian roots — he was born in China — and the topmost tips of Florida's picadita sweet-potato plants. His devotion to the purple-skinned picadita, a staple crop in sourthern Florida, project began three years ago when he wondered why the sweet potatoes in a field near his home were not being harvested. He dug up some and took them to Thomas Davenport, an expert who formerly worked at University of Florida's Tropical Research & Education Center. Davenport said the potatoes were infected with a wood virus.

David set out to find a method of propagating healthy plants from infected plants. What he developed is a way to grow plants that are free of pathogens — "no viruses, bacteria, or fungi that reduce overall yield and quality," he says. That's because they're cultivated from meristematic tissue, the very tip of the plant. This immature tissue hasn't yet developed vascular bundles, which are the pathways through which viruses and bacteria typically spread. In effect, David explains, "the top segment of any meristem is temporarily escaping the spread of viruses."

So, if the extreme tip is snipped off — his cuttings are no more than 1 millimeter long — and regenerated using tissue-culturing techniques, the new plants will be naturally virus-free. David says this approach could be adopted anywhere sweet potatos are grown and boost crop yields.


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COMMENTS On The Issues

Where would the extra R&D funds come from? From grants to religious groups. President Bush's faith-based initiatives topped $1.1 billion in 2003, according to the Washington Post. I support the full separation of church and state, so I am not a great supporter of President Bush's enthusiasm for dishing out federal money to groups based on their religious affiliation. Although these groups are given money to "help the needy", the same good could be done by an improved federal welfare system that would cost much less to implement.

INTEL SCIENCE SEARCH FINALIST David Q. Ying

David Q. Ying


Coral Reef Senior High School
Miami, Fla.


Hobbies: Badminton, tennis, table tennis, football, basketball, swimming


Ambition: Physician or biomedical engineering