About 90 percent of the 471,000 acres of rice grown in California last year was seeded with varieties developed through the rice breeding program, which has released 36 improved varieties since 1969. In 2001 foundation seed of 14 public rice varieties and basic seed of two Japanese premium quality varieties were produced on 146 acres at the RES. Progress continues in all grain classes. For instance, in 1999 the Newrex type L-205 and the basmati-type Calmati-201 were released and are doing well.  Intensified premium quality breeding efforts have led to the development of Calhikari-201 and M-402. Calhikari-201, the first premium quality short grain for California, continues to show superior agronomic performance and yields. Eight premium quality short-grain breeding lines were advanced for earlier maturity, smooth hull, different parentage, kernel size or better yield potential than Calhikari-201. Growers are responding well to the two new Calrose medium grains—M-104 and M-205—released in 2000. These new varieties are filling important niches at the expense of the long-time industry standard M-202, which was grown on significantly less acreage in 2001—232,765 acres (compared to 353,879 acres in 2000). Finally, in the Rice Breeding Program section of this report, a very early to early, high yielding experimental line, 98-Y-242, that has shown solid yield stability could replace M-202. Breeder seed of this line was produced in 2001 and foundation seed increase is scheduled for 2002.

Before any prospective new variety is released to the growing public, it must undergo rigorous testing in Statewide Variety Trials. These tests conducted at 16 on-farm locations through the state and at the Rice Experiment Station, provide a “reality check” for new entries and commercial standards. The Variety Trials section also reports on a small-plot nitrogen management trial comparing six varieties (M-205, M-402, L-205, CT-201, M-104 and M-202) at six preplant N rates and the development of a leaf color chart for a quick in-field assessment of nitrogen status.

California growers have spent more than a decade reinventing some aspects of rice farming since passage of the California Rice Straw Burning Reduction Act in 1991. An experiment continued to determine the maximum yield potential of rice following prolonged straw incorporation. After eight years of studying alternative rice straw management, grain yields compared well to burned fields. The section Potential Straw Incorporation Impact on Yield reports on the important relationship between straw management and optimal nitrogen fertilizer applications.

Maintaining Rice Quality After Harvest is the title of another rice management project that has become increasingly important to grower returns. In its third year, this project analyzed the effect of holding time and rice moisture content on off odors; the amount of moisture that can be removed in drying without head rice loss; the effect of harvest moisture on head rice and grower returns; and the effectiveness of moisture meter calibration.

The goal of the project Measuring Crop Water Use was to develop more current information to be used by industry, water purveyors and policy makers. Previous estimates of rice crop water use were based on studies from the 1960s. Much has changed since then, including the advent of short-statured rice varieties and methods to estimate crop water use. A study was conducted at a California Irrigation Management Information System (CIMIS) station at Nicolaus and a nearby rice field. It estimated seasonal water use at 37.3 inches, considerably lower than the 42 inches typically reported for the Sacramento Valley.

Previous studies—and grower experience—have shown that cool air temperatures during panicle formation may lead to pollen sterility and hence to blanking and yield reductions. Water temperature has become a relatively recent matter of concern because of regulatory agencies efforts to improve habitat quality for fish. A new project was begun last year to document the effect of low water temperature on blanking and grain yield. As reported in Water Temperature Impact on Blanking and Yield, researchers quantified water temperature yield losses in grower fields. Low water temperature reduced yields by delaying crop growth. These effects are even more important during the early growing period.

Weed Control in Rice is typically at the forefront of grower concerns where protecting the rice crop is concerned. Promising new herbicides such as those that go under the trade names Command, Clincher and Shark get close scrutiny at different rates, timings and application methods. Prompted by the need to ensure genetic purity as established by the California Rice Certification Act (CRCA), a large experiment was initiated in 2001 to determine maximum distances necessary to prevent pollen migration from transgenic to non-transgenic rice.Work on herbicide toxicity, watergrass resistance, rice-weed competition and Clearfield Rice, a non-transgenic mutant breeding technology, are also reported on in this section.

An investigation was begun last year into Delayed Phytotoxicity Syndrome (DPS), It is a serious problem in some parts of the Central Valley and is characterized by stunted rice plants. DPS has been linked to the rice herbicide thiobencarb (Bolero®). Environmental toxicologists report what they’ve learned about DPS in the section Microbial Degradation of Rice Pesticides.

The good news where rice diseases are concerned is that rice blast was “of little consequence” in the 2001 California rice crop. It was not observed until mid-August and then only in a few fields where it has been known to occur in previous years. In the section Cause and Control of Rice Diseases, growers will find information on fungicide trials and find advice on dealing with the newest threat, Bakanae disease. A related project reported in Implementation of a Rice Blast Warning System describes the intricate monitoring network evolving to help track blast outbreaks before they can cause widespread crop damage.

The 2001 adult rice water weevil (RWW) flight was the heaviest in five years. Studies continued in small ring plots at the Rice Experiment Station and in grower fields to compare experimental materials with registered standards and to improve management of the existing products. In the section Protection of Rice from Invertebrate Pests entomologists also report work on the relationship between RWW and straw management and susceptibility of different varieties to RWW damage.

In Rice Utilization and Product Development learn how food scientists at the USDA’s Western Regional Research Center in Albany and at UC Davis continued their work on textural properties of rice, shifted the study of the health-promoting properties of rice to diabetes and began analysis of an Asian sprouted rice product.

Rice straw is a major feed resource in some parts of the world. Because of the disposal problems now facing the California rice industry, using rice straw as a feed supplement for livestock is getting increased attention here. As reported in Rice Straw Maceration for Feedlot Cattle, researchers are examining whether a macerator—a mechanical treatment—could also make rice straw more palatable to livestock in feedlots.

Finally, as it has for 20 years, the Sacramento Valley Fall Burn program continues to perform admirably, minimizing impacts to the air quality in the communities where rice is grown. Regulatory changes reduced the amount of open rice field burning to 43,680 acres last fall.

As always, the Rice Research Board is committed to finding science-based solutions for the many challenges in our industry. Our success is due to the dedication and collaboration of many individuals. We appreciate your input and on-going support, and sincerely thank you for your contributions. Best wishes for a trouble-free and profitable growing season.