Every August, California rice growers gather at the Rice Experiment Station (RES) near Biggs, Calif., to find out what the station’s talent has been toiling away on for months and years. The annual Rice Field Day is much anticipated and well attended. After all, if you’re going to grow rice in a competitive world market, it helps to keep up to speed.
One portion of the field day highlight is a wrap-up and preview of varieties in development as well as comparisons to some of the tried and true standards. Often, the standards get left in the dust as new and better varieties emerge on the horizon. The 2009 Rice Field Day was no exception. Kent McKenzie, director of the California Rice Experiment Station, is especially enthusiastic about the rice station’s new DNA technology.
“A new DNA marker lab at the station has been established and now has a full time lab technician,” he told attendees at the field day. “This resource has greatly enhanced the station’s capability to identify molecular markers quickly and incorporate selected genetics into experimental lines.”
DNA marker technology takes much of the guesswork and tedium out of traditional plant breeding, allowing researchers to focus more precisely on incorporating specific traits, such as quality and disease resistance into experimental varieties.
“The DNA marker technology is evolving exponentially and enabling us to make rapid advances in incorporating desirable traits into our breeding programs,” McKenzie says. “More than half of our efforts in regard to DNA markers are currently supporting the medium grain program, but we are also using it to identify other desirable traits such as the waxy gene marker in the long-grain program and premium quality markers in the short grain program. That’s just the tip of the iceberg. This technology is going to revolutionize how we develop new varieties to bring to the market.”
Short grain program
The short grain program at RES has a challenging multi-pronged goal that includes excellent grain quality, high yield potential, disease resistance and adaptation to cooler growing conditions.
“The only regular short grain variety still in commercial production in California is S-102, which was released in 1996,” Virgilio Andaya, RES plant breeder, told field day attendees. “It is a high yielding, early maturing variety with resistance to cold blanking. It also has a large kernel size. However, its drawback is its susceptibility to stem rot, pubescent hull and low overall eating quality.”
For several years, the emphasis in the breeding program shifted away from conventional short grain varieties toward the development of premium quality short and medium grain varieties. However, that resulted in fewer regular short grain varieties making it through the preliminary yield trials.
“In 2008, we reconsidered that strategy and started crossing high yielding medium grains and premium quality grains with regular short grains on a large scale,” Andaya says. “We think this will add diversity and allow us to recombine desirable traits that each offer.”
In the premium short grain category, efforts are underway to improve on the grain quality of CH-201, which was released in 1999. While the variety has many desirable production attributes, it does not compete well with Koshihikari, making it less acceptable to the Japanese market, according to Andaya.
“We have a premium quality short grain variety in the state-wide test, designated as 04-Y-177, that has a cumulative yield advantage over CH-201,” he says. “It has a higher milling yield, better blanking resistance and better overall cooking quality scores. This variety looks promising.”
Long-grain program reacts to
California’s rice production acres are primarily dominated by short and medium grain varieties. According to the USDA, California has 4,000 acres of long-grain rice this year, compared to 9,000 acres last year. That compares to an estimated 495,000 acres of medium grain rice this year and more than 50,000 acres of short grain rice.
Long-grain rice comprises somewhat less than one percent of California’s rice acreage. However, market demand seems to be changing that dynamic.
Historically, long-grain varieties have not been very well adapted to California’s temperate growing environment, as they are traditionally more suited to tropical climates.
However, research efforts at RES are identifying germplasm that could result in the development of more conventional long-grain and specialty long grain varieties for California.
Farman Jodari, RES plant breeder gave an overview of the long-grain program at the 2009 Rice Field Day. In recent years, the genetic bank of long-grain breeding material has been significantly expanded as a result of searching for germplasm from southern U.S. growing regions as well as worldwide collections, according to Jodari.
“This diversity is being used to incorporate desirable agronomic and quality traits into California lines,” he told field day attendees. “ In 2008, the lower than average degree day accumulation gave us an excellent opportunity to identify and advance long-grain breeding lines with better adaptability to cooler climates.”
Since 1912 when the rice breeding research program began under the auspices of RES, the goal has always been the development of improved varieties of all grain and market types to sustain high, stable yields and quality with minimal environmental impact for the benefit of California rice growers.
As technology has evolved, the industry has flourished in spite of often difficult challenges.
Medium grain program
Favorable prices for paddy rice largely drive grower demand for Calrose medium grain when it comes to variety selection. It is one of the reasons DNA marker technology efforts at the station have been channeled to developing improved yield, cold tolerance and earliness. Early Statewide Yield tests in 2008 confirmed again that M-206 and M-208 still hold an advantage over the older M-202.
“We don’t want to get too comfortable with that,” Jacob Lage, RES plant breeder, told field day attendees. “We want to introduce ‘new blood’ into the medium grain rice gene pool. For several years, we’ve been breeding lines that have a Chinese parentage and they are being tested in the very early and early statewide yield tests. The goal is to improve yield, cold tolerance and earliness.”
Other goals in the medium grain program include not only improving yield, but also improving milling yield, according to Lage. “Recent trends in harvesting paddy rice at lower moisture content can result in severe drops in milling yield, especially in older varieties such as M-202 and M-104. However, M-206 and M-208 have a longer window for harvest without negatively impacting milling yield.”
A very early experimental line, 05-Y-471, looks promising in terms of yield, early heading and milling yield. “It’s the milling yield that makes this line look particularly attractive,” Lage says. “In milling studies at the station, 05-Y-471 was two to four percentage points better milling yield than M-104 at harvest moisture content of 23 percent above 18 percent.”
When the rice was further dried, the experimental line continued to shine, while the milling yield of M-104 dropped to 45 percent at just below17 percent. That compared to 05Y-471, which turned in a milling yield of 58 percent at 16 percent moisture content.
“This line would be attractive to growers who wish to prioritize part of their acreage to a more stable, very early variety,” Lage says. “It could provide an extended harvest season and lower water usage, without risking milling yield penalty. It may also be a good choice in colder areas with similar blanking tolerance to M-104.”
Brenda Carol is a freelance writer based in California. Contact her at (805) 226-9896 or firstname.lastname@example.org.