• By Vicky Boyd,
Rice breeders at the California Rice Experiment Station are on a roll, having released nine improved varieties in the past 10 years. And their success appears to be continuing as they have two lines — 12Y2175 and 14Y1006 — being considered for potential release in the next few years, said Virgilio “Butz” Andaya, director of plant breeding at the grower-owned Biggs, California, station.
“We want to replace the older varieties,” he told attendees at the station’s recent Rice Field Day. “We have a lot of material in the pipeline, and we can’t move through them if there are older varieties that are still there. We can only handle so much foundation seed.”
In 2018 statewide trials, the medium-grain 12Y2175 yielded 10,031 pounds per acre, topping the industry standard M-206 (9,182 pounds) and M-209 (9,241 pounds), Andaya said. Its days to 50% heading are similar to M-209, but the newcomer has parentage, taste and texture characteristics closer to those of the premium medium-grain, M-401, than to Calrose medium-grain varieties. The line is in seed increase for possible release in 2020.
The long-grain line, 14Y1006, also performed well in 2018 statewide states, averaging 10,620 pounds per acre compared to 9,770 and 9,900 pounds per acre for L-206 and L-207, respectively. It is an early maturing sister line of L-207.
The newcomer has similar milling yields to L-207, but the grains are less chalky. It also is considered lodging resistant and cold resistant.
ROXY Rice work continues
The Rice Experiment Station also continues to move forward with developing an herbicide-tolerant rice system known as ROXY Rice, said Kent McKenzie, director of the Rice Experiment Station and a rice breeder.
The trait was developed by traditional induced mutagenesis, which has been used on a variety of crops, including semi-dwarf rice varieties and M-401. A trademark already has been issued for the ROXY trait, and a patent currently is under examination, he said.
Last year at the rice field day, McKenzie announced a partnership with Albaugh LLC, an Ankeny, Iowa-based marketer of post-patent crop protection materials. It will provide the herbicide, oxyfluorfen, that will be paired with ROXY Rice.
A Group 14 PPO herbicide, oxyfluorfen is not registered for use in rice in the United States. But it is labeled for weed control on a board array of other crops, including soybeans, corn, cotton, tree fruit, grapes and nuts.
In rice, the herbicide is effective against watergrass, including those biotypes resistant to other modes of action. It also controls several broadleaf weeds, including duck salad.
McKenzie said Albaugh hopes to submit a registration package to the U.S. Environmental Protection Agency, with a concurrent submission to the California Department of Pesticide Regulation, in 2020.
With a new genetics lab up and running at the Rice Experiment Station, breeders have been able to gain a better understanding of the ROXY trait and where it is located within the genome.
The station currently has two medium-grain ROXY lines, 17Y3000 and 19Y4000, it will use to make crosses to develop improved varieties.
Other research highlighted during the Rice Field Day included:
• Using technology to determine whether a mid-season nitrogen top dressing is needed. University of California rice agronomist Bruce Linquist discussed how a GreenSeeker handheld, coupled with a high-nitrogen reference strip, could helped determine whether your crop had enough nitrogen at panicle initiation.
He also is conducting preliminary research to determine whether drone and satellite imaging could provide similar information to growers. Not only is applying nitrogen to rice when it isn’t needed an added cost, but it also can promote disease and lodging.
• Tadpole shrimp, a pest of seedling rice, is becoming less susceptible to the standard pyrethroid treatment. As a result, UC Cooperative Extension rice systems adviser Luis Espino is looking at other controls, including Sevin (carbaryl), Belay (clothianidin) and copper sulfate.
Espino also is conducting fungicide trials on kernel smut – an emerging problem – as well as aggregate sheath spot and stem rot.
• UC Extension weed specialist Kassim Al-Khatib continues to fine-tune weed control programs that include Butte, a benzobicyclon herbicide from Gowan Co., and Loyant, a Corteva Agriscience auxin herbicide not yet registered in California. Loyant was registered in the Mid-South in September 2017.
Butte is only registered for use in California. Registration of a similar product, Rogue, for the Mid-South is in the works.
“Weed control is probably the No. 1 issue that our growers face,” he said. “And if we think about why it’s important for growers, if growers don’t get good weed control, they can lose at least 50% of their yield.”
Weed control becomes even more problematic with increasing resistance to several modes of action. In fact, Al-Khatib said he tested one weed last year that was resistant to five different modes of action.
The other challenge is the price of herbicides.
“They’re very expensive,” he said. “With the price of the commodity, the grower has a hard time to justify using that much money just to control weeds.”
In addition to Butte and Loyant, Al-Khatib also is conducting trials to determine where an experimental product from Nichino America, NAI-1883, might fit. Known chemically as pyraclonil, the herbicide is the most widely used rice weed control product worldwide. It belongs to the Weed Science Society of America’s Group 14, the same group to which Shark herbicide belongs.