Researchers discuss new lines, genetics and milling concerns

Extremely hot, dry weather could mean milling troubles for some of the Arkansas rice crop.

“It's been rather dry in north-central Arkansas for a while,” said Karen Moldenhauer, University of Arkansas rice breeder, at the recent Cache River Valley Seed field day near Cash, Ark. “In the southern part of the state, though, there has been a lot of moisture — more rain in July than I can ever recall in the 25 years I've been here.”

Now, however, it's turned hot and dry — even at night. That, says Moldenhauer, points to problems with milling.

“The early rice that was planted in March came through the cold, is doing very well and will likely have good milling yields. However, any rice that was heading just prior to or during this hot weather, or rice which was still grain filling during this hot weather, will probably have more milling problems.

“Anytime temperatures are above 72 degrees at night, the rice plant has to work to stay alive. It gets no rest and some of the starch that should be going into the grain is being used to keep the plant alive at night.

“It's true there have been plenty of days when, for a very short period during the morning, temperatures reached 76 or 77. But at 10 p.m., the temperature is still around 90. That means this will probably be a poor milling year.”

Moldenhauer said there are exciting new varieties and lines in development. One that's getting a lot of interest is CL 171AR, a Clearfield variety.

“This is much like CL 161 because it has the same kind of yield potential, same kind of milling, same color. But its big benefit is the disease package.”

Over a dozen new Clearfield lines are being grown in plots around the state. “I'm just waiting on data from those tests to see which lines are best to keep in the testing program.”

Parentage of the lines includes CL 161 crossed with Drew, Francis and Wells. “Then there are lines I selected out of the initial Wells/CL 161 cross — not necessarily CL 171-AR — that were crossed with Drew and Francis. That's the kind of material we're looking at.”

In last year's test, the experimental lines had much higher yields than any of the traditional lines.

“We'll see how they do this year. But they do have better yield potential than CL 161, CL 171, CL 131 and CL 151. Unfortunately, we don't have CL 131 or CL 151 for comparison this year.”

Some of the lines being studied have excellent milling yields. “We think of CL 161 as having great milling yields but some of these are much better.

“One of the advantages of having late-planted tests last year was the milling yields were effected. Things we'd expect to yield very well like, CL 161 or CL 171, milled in the mid-50s. But there were lines milling in the low- to mid-60s. That's why we're very interested in those lines.”

CL 161 has been around for five years and will continue to be on the market, promised HorizonAg's Lance Schmidt. The key to CL 161 is sheath blight management and seeding rates.

As for CL 171-AR, “characteristics seem to fit well with what the rice industry needs: improved disease tolerance, much better blast and sheath blight resistance,” said Schmidt, whose company is responsible for bringing Clearfield varieties to market. “Yield-wise, the potential is very good. I've seen fields of it that are impressive. I'm anxious to see the yields they produce.”

Some of the data coming out of Louisiana's harvest “is very good — better even than CL 161, one of the better milling varieties on the market.”

John Greer, manager of the Burns Seed Farm near Cash, said CL 171-AR has done well in a “more problematic field with high pH and sodium. Problems can show up in the advanced seedling stage.

“When a new variety comes along, I plant it in areas where I've had problems to see if there's any response. This field doesn't do well in Wells or Cocodrie.”

However, CL 171-AR is showing tremendous tolerance. “It isn't a cure-all, but compared to the other two varieties, CL 171-AR is doing very well.”

Moldenhauer's colleague, UA rice breeder James Gibbons, is currently working with delayed harvest. That's because “we want to make sure we have better-milling varieties in the future. Delayed harvest is one way to do that. If we can leave it in the field longer, we can find out how it'll mill under many different conditions.

“(Gibbons) has techniques where he can take samples, put them in moisture, dry them and then get data on delayed harvest.”

Gibbons is also looking at indica lines. The indicas are from Asia and don't have the same cooking quality as rice grown here. But he's working to get that cooking quality combined with the indicas' better disease resistance and high yields.

“It's important for us to get material from other countries and bring it here,” said Moldenhauer. “Rice isn't native to the United States. If we want to get the most out of rice, we need to have a good exchange system with other countries. (Gibbons) is working very hard on opening up exchange routes. He's brought in some very good germ plasm.”

For several years Moldenhauer has also worked with some experimental lines in attempts to obtain blast resistance.

“We're finally getting some early lines out of that work. Those early lines are probably 63 to 67 days — very early. For comparison, Spring is around 73 days and Trenasse is around 77 days.”

Some of the very early lines have good cooking quality and blast resistance. “We're trying to get a not-too-tall plant height with good blast resistance and early characteristics.

“We've crossed those to Francis, Wells and other later varieties with high yield potential.”

As for medium grain rice, Bengal is on about 9 percent of Arkansas' rice acreage this year. Jupiter appears to be better than Bengal on disease resistance.

“Last year, Kellogg's said it would accept Jupiter. That's one possible line farmers may be looking at in the future. I think Kellogg's will continue to like Jupiter. I certainly hope so.”

On 37 percent of Arkansas' rice acreage, Wells is the major variety in the state. Francis is on 12 percent, CL 161 is on 10 percent, and Bengal is on 9 percent. After that, many varieties take small bites of the state's acreage. Added all together, the Clearfield lines are on about 20 percent of the acreage.

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