Noal Lawhon says his impression of what farmers may think about the new Clearfield rice system can be summed up very succinctly: "If you like Roundup Ready soybeans, you're going to love Clearfield rice."

Clearfield is the name that has been given to rice that is tolerant to the imidazolinone class of herbicides. Tim Croughan, a scientist with the Louisiana State University AgCenter, discovered the herbicide-resistant rice, which is being developed into commercial rice varieties through a joint agreement between LSU and BASF Corp.

"We were talking about how well Roundup Ready soybeans have been accepted," said Lawhon, speaking at the annual Delta King Seed Co. field day. "Judging from the comments we've had from farmers and seed dealers, 75 to 90 percent of the soybean acres this year have been planted to Roundup Ready varieties.

"We believe Clearfield rice will prove to be as big a winner with farmers as Roundup Ready soybeans."

Lawhon, president of McCrory, Ark.-based Delta King, is one of the organizers of a new venture named Horizon Ag Inc. Horizon will market new rice varieties that are tolerant to the Clearfield herbicides.

Horizon is looking at three lines of the new rice, one of which was on display at the Delta King field day at Shoffner, Ark.

"Let me talk about where these varieties came from," said Dwight Cowan, CEO and general manager of Horizon Ag. "Last fall, LSU released three candidates for development under the Clearfield system to us.

"In recent years, LSU has selected out a rice strain with natural tolerance to imazethapyr," he said. "They have now used a natural breeding program to put that trait into rice varieties that are agronomically sound."

The three candidates were planted in winter nurseries in Puerto Rico last fall and brought back to the United States last spring. The varieties were then planted under experimental use permits in each of the major rice-growing areas.

"The Clearfield rice plot has 4 ounces of imazethapyr applied to the soil right after planting," said Cowan. "These plots were planted on May 18, relatively late, and sprayed the next day. It received a postemergence application of 3 ounces of imazethapyr prior to the flood.

"You can see that we have a tremendous amount of grass pressure in the check plot, but the Clearfield rice is clean."

Cowan said Horizon planted the varieties in all of the rice-producing states in the South to try to find out how well they adapt to different cultural practices and different herbicide programs in those areas.

"We also have them in all the university trials, the state variety performance trials, the seeding trials, the fertility trials to learn everything we can so that we can provide that information to growers about how best to manage these varieties when they come to market."

This fall, Horizon will assess the three candidates to determine how and when the company will release them. "If they perform well, we could have all three available," he said. "If not, we could have one or two.

Cowan said the feedback from growers involved in the trials has been positive. "They really like the early vigor of these varieties, and they like the earliness. All three are early varieties and two are very early varieties."

One of the three long grain varieties, 0051, is similar to Cypress in earliness. The second, 2551, is similar to Cocodrie, and the third, 3291, is six to seven days later.

"Each of the varieties, which were selected from many crosses made by Steve Linscombe at the LSU Rice Research Station, has similarities, but is also different from the parents," said Cowan.

If all perform, Horizon officials expect to have enough seed for farmers to be able to look at some of the rice in their area in 2001. Full-scale commercialization of the varieties is expected to occur in 2002.

"BASF has submitted its registration package for imazethapyr on rice to EPA, but they expect it will be 2002 before they receive a full label," said Cowan. "They have also said they will support any requests for Section 18 emergency exemptions for Clearfield rice in 2001."

Cowan was asked if he expected any yield reduction with the Clearfield rice. "These are not transgenic varieties - they were developed through a natural breeding process. We believe they are good-yielders. We'll know more in 60 days."

He said red rice is "very susceptible to imazethapyr. Imazethapyr is a broad-spectrum herbicide that has been more commonly used in the Midwest. But, we know it will need some help on hemp sesbania and indigo."