Saturday, March 16, 2013

The Secret Of The Four-Leaf Clover

Researchers led by a University of Georgia plant scientist have figured out the genetic secret of the four-leaf clover.

Wayne Parrott 
Richard Hamm
Credit: Richard Hamm

But Wayne Parrott didn't find the gene for the rare four-leaf trait through a lucky stroke or help from leprechauns.

It took 18 years of research and modern DNA analytical techniques to find the gene, said Parrott.

Parrott, who came to UGA in 1988, worked with UGA graduate student Rebecca Tashiro and other researchers at UGA and Oklahoma's Noble Foundation to find the four-leaf gene.

Looking for the lucky four-leaf clover gene has been a sort of sideline from Parrott's more traditional research projects, such as trying to improve switchgrass to be a better raw material for biofuel production. He's also developing soybeans that can resist insect pests and nematodes.

"This has been a sort of fun project," he said.

Parrott has been fascinated by the genetically complex clover plant since he was a Kentucky teenager.

He remembers the day one of his dad's cousins taught him how to find four-leaf clovers.

The secret: Don't get on your hands and knees to look for the rare four-leafers leaf by leaf - that will take forever. Just look around for a break in the pattern formed by thousands of little plants with three leaves - and that break in the pattern is likely to be the rare four-leaf clover.

Scientists have been trying for a century to tease out the secret of why clover sometimes produces a plant with four leaves instead of the usual three.

"It's such an incredibly cool plant," said Parrott, who treasures the plant's seemingly infinite color and pattern variations and its genetic complexity.

In addition to the four-leaf gene, Parrott and his fellow researchers found the rare gene that gives some clover plants red flecks, and another rare gene that lends other variants a pattern of red leaf veins.

Now Parrott is using traditional breeding methods to develop new clover varieties that will show off the plant's hidden beauty.

"There's just so many combinations of colors and shapes that we can do; we should be able to develop a whole series of varieties," Parrott said.

The plant scientist has filled much of a UGA greenhouse with pots of potential varieties. Small flower beds outside the UGA AGTEC building off Riverbend Road, where Parrott's laboratory is, serve as trial gardens for some of Parrott's clover plants.

Most people think of clover as forage or a lawn weed, but Parrott hopes to see some of the new clover types he's developing planted in Southern flower gardens.

"I really think it has great potential as a bedding plant," Parrott said. "I think it can fill a niche, something besides pansies and ornamental kale."

To find the right plants to breed, the researchers first used a modern technology called genetic fingerprinting that finds plants with the right genes - the genes for color and for the color variations Parrott likes.

Cross-breeding clover plants with different genetic traits, Parrott grows about 1,000 new plant types a year. But only a small fraction have the color or leaf pattern characteristics he's looking for.

"If you start out with about 1,000, one to four will be suitable for a variety," he said.

In addition to new, colorful clover varieties, Parrott also wants to breed plants with the four-leaf gene. His aim is a variety that will produce more four-leaf sprigs than the plants you'd normally find in your frontyard - but not a variety with nothing but four-leaf sprigs.

That would be boring, he figures.

Contacts and sources:
Inside Science TV (ISTV)
University of Georgie
Lee Shearer

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