New kids on the block

Horizon Ag, University of Arkansas join to introduce two Clearfield varieties.

• By Vicky Boyd,
Editor •

AR1111 new Arkansas Clearfield long-grain

The new Clearfield long grain, CLL15, exhibited consistent yield potential in strip trials from Louisiana to the Missouri Bootheel during 2018. It was developed by the University of Arkansas and shown off during its 2018 Rice Field Day in Stuttgart under experimental numbering — photos by Vicky Boyd

In partnership with the University of Arkansas and BASF, Horizon Ag plans to introduce two Clearfield varieties for seed production this season and for commercial planting in 2020.

The new long grain and new medium grain were released by the University of Arkansas and are from the breeding program of Dr. Xueyan Sha at the Rice Research and Extension Center in Stuttgart, Arkansas. They also mark the first Clearfield releases from Sha since he arrived at the university.

CLL15 and CLM04 are just the latest two varieties in various stages of development by Horizon Ag and its university breeding partners. What these introductions mean to existing Clearfield varieties will depend on market demand, says Dr. Tim Walker, Horizon Ag general manager.

“We will continue to add materials to the pipeline, and varieties will come and go,” he says. “CL172 is probably going to be a short-lived variety. Then the question will be what do we do with CL151 and CL153? A lot of that will depend on the first two years of CLL15 being out there.”

Consistency from south to north

Developed using traditional breeding techniques, CLL15 — known experimentally as CLX1111 — contains the Pi-ta gene as well as the Pi-kh gene. In combination, they offer a very strong blast package similar to that of CL153 and CL172, Walker says.

In theory, having two genes provides resistance to a broader spectrum of blast pathogen races, Sha says.

“But it’s no guarantee, and it depends on the race dynamics,” he says. “That’s why I always try to bring in some new resistance genes.”

Sha says the long-grain parentage of the new line involves multiple elite breeding lines derived from several old varieties developed by the University of Arkansas and Louisiana State University AgCenter.

During 2018, Horizon Ag conducted several strip trials from Louisiana north to the Missouri Bootheel with CLL15 and two other potential Clearfield long-grain releases.

“One of the things we really liked about this variety (CLL15) was how consistent it was from south to north, and it was right there with CL151 in Louisiana from a yield standpoint,” Walker says. “And it was better than 151 in other strip trials.”

In the 2018 Arkansas Rice Performance Trials in 10 locations, CLL15 yielded an average of 192 bushels per acre compared to 190 bushels per acre for the competitive hybrid, CLXL745. In the trials conducted from 2016 –2018, CLL15 averaged 191 bushels per acre compared to 197 bushels per acre for CLXL745.

CLL15 milling yields are similar to CL153 and CL172, Walker says. It also appears to have low chalk and produces a kernel suitable for the packaged rice market.

“CL153 and CL172 are newer releases, and they’re both very good millers,” he says. “Again, our approach really since 2011 has been to bring yield and quality along at the same time, understanding the issues we have in the industry.”

Standing 38 inches tall, CLL15 is a true semi-dwarf and has much better standability than CL151, Sha says. It has similar maturity to CL151, with both reaching 50 percent heading in 83 days. CL153 is slightly later, reaching 50 percent heading in 85 days.

Sha made the initial cross in 2013, and the CLL15 variety is available for commercialization about seven years later. Walker credits Sha and Dr. Steve Linscombe, retired Louisiana State University AgCenter rice breeder, with maximizing use of the winter rice nursery in Puerto Rico.

“By them taking full advantage of the winter rice nursery, the process from start to finish is a little bit quicker,” Walker says, adding it probably shaves about a year off commercialization.

Sha says he travels to Puerto Rico about six to eight times per year to check on new varietal development. Although the facility provides two additional generations per year, he only uses it during the early breeding stages and for seed increase.

Strip and on-farm trials still need to be conducted in the Mid-South where farmers will be growing the varieties commercially, Sha says.

Barring unforeseen problems, Walker says they expect to have about 70,000 cwt of CLL15 seed available for planting up to 100,000 commercial acres in 2020.

For 2019, Walker says Horizon Ag will have no fewer than three advanced Clearfield lines in strip trials and university performance trials. From those, no more than two could possibly be released in 2020 for seed production.

New Clearfield medium grain

CLM04 new Clearfield medium grain

CLM04 is a new Clearfield medium grain with a two-gene blast package and strong yield potential. It, too, was bred by the University of Arkansas.

The Clearfield medium-grain release, CLM04, offers yield potential comparable to conventional Jupiter and Titan plus two-gene blast resistance and Newpath herbicide tolerance. Jupiter, on the other hand, only contains the Pi-ks gene for blast resistance.

Like CLL15, CLM04 – known experimentally as CLX1030 — was developed using traditional breeding techniques. It draws its parentage mostly from Jupiter, as well as from Neptune, Bengal and CL161, Sha says.

The new release has similar maturity to Jupiter, reaching 50 percent heading in 86 days compared to Jupiter’s 87 days. Titan, on the other hand, reaches 50 percent heading in 81 days.

In 43 trials conducted in Arkansas and throughout the Southern United States, CLM04 yielded an average of 198 bushels per acre compared to 195 bushels per acre for Jupiter and 200 bushels per acre for Titan.

“CLM04 appears to really hold with Jupiter and Titan, especially in Arkansas,” Walker says. “A lot of people are growing Jupiter without a contract because of the yield potential. I think that trend follows with Titan, so CLM04 really gives both those varieties a run for the money.”

CLM04 also appears to have more yield stability than the previously released Clearfield medium grain, CL272.

Amylose content and gelatinization temperatures are almost identical for CLM04 and Jupiter, which Kellogg’s has approved for use.

Walker says they have entered Kellogg’s testing protocol with CLM04, but it will be at least a year before they have a final answer.

The results from each of two small samples Sha has already sent Kellogg’s came back as satisfactory. Currently, he is working to send 1,000 pounds of CLM04 for a pilot-scale run.

“We’re trying to do whatever we can to speed up the approval process,” Sha says.