Rice Farming

Pipeline Holds Potential

Arkansas rice breeders share ‘sneak peek’

By Dr. Karen Moldenhauer
and Dr. James Gibbons

The University of Arkansas Division of Agriculture rice breeding program based at the Rice Research and Extension Center in Stuttgart always has new breeding lines at various stages of development.

We grew foundation seed this year of breeding line 41182, which originated from a cross made in 1998. And we have just finished making hundreds of crosses that will produce improved breeding lines over the next decade.

Lines 41182 and 61188 were both grown this year to produce foundation seed for potential release to seed growers in 2009. They both have had yield potential similar to that of Wells and Francis in the Arkansas Performance Trials (ARPT) for the last two to three years.

In addition to high yield potential, 41182 has the major gene, Pi-ta, which confers resistance to the common blast races in Arkansas, and the minor genes necessary to be “moderately resistant” to “resistant” to the race IE-1k. Rice blast (Pyricularia grisea) can be a devastating disease in Arkansas.

More about 41182 and 61188
The parentage of line 41182 includes several varieties familiar to rice producers: Drew, Newbonnet, Dawn, CI9695, Starbonnet and Katy. This line had an average yield of 197 bu/acre in the ARPT 2005–2007, which is similar to Francis and Wells at 202 and 199 bu/acre, respectively. Milling yields of this line are better than Wells.

Line 61188 has the longer and larger kernel size desired by the industry. It was also grown as foundation seed in 2008 as a potential release to Arkansas seed growers in 2009. It has high yield potential, testing at 198 bu/acre, comparing favorably with Wells and Francis for the years 2006-2007. Even with the larger kernel, 61188 had a better milling yield for those two years than Wells.

An aromatic line is being considered as a potential future release. It is a semidwarf and non-photoperiod-sensitive line and can produce seed during the normal growing season in Arkansas.

2008 head-row lines
Many other lines in the program have improved characteristics, and several were in head rows this season.
The line 81076 in being grown in head rows for possible foundation seed production in 2009. Line 81076 yielded 215 bu/acre in the 2007 ARPT compared to Wells and Francis, which each yielded 185 bu/acre. Milling yield averaged better than both Wells and Francis.

Another potential future release is line 71124. It is a very early semidwarf similar to Spring in maturity. It has good blast resistance and milling yield potential.

Three Clearfield lines were grown as head rows in 2008 and will be considered for potential release to BASF this fall. One line, IMI113, had very good yield potential in the 2007 ARPT. It is a little taller and has the larger kernel size, but its milling yield is not as good.

The other two, IMI091 and IMI055, are semidwarf lines with better milling and acceptable grain yield. Lines IMI091 and IMI055 yielded 182 and 164 bu/acre, respectively, in a Clearfield test at two locations, compared to CL161 and CL171-AR at 100 and 153 bu/acre respectively in the same test. These and several other Clearfield lines will be evaluated further.

Data from the Arkansas Rice Performance Trials (ARPT) conducted at Stuttgart, Keiser, Rohwer, Clay County, Pine Tree and Jackson County in 2008 will be available in December in the Extension Service Information Sheet, “Arkansas Rice Performance Trials, 2006-2008,” online at www.uaex.edu, Agriculture, Agronomy, Rice.

Drs. Moldenhauer and Gibbons are rice breeders with the University of Arkansas Division of Agriculture. Contact them at kmolden@uark.edu, jgibbon@uark.edu.