Lee Jackson, retired Agronomy Extension Specialist, provided this disease update after his most recent visit to several UC variety nurseries around the state:
It has been a low rainfall year for most of the spring. Production on irrigated acreage will be average to above average, but extreme drought stress in rainfed regions, particularly the foothills surrounding the San Joaquin Valley and similar areas, will result in very limited, if any, grain production. Typical is the UC Regional Wheat nursery near Ducor, Tulare County, where most plants have senesced (or died) prematurely without producing grain.
With regard to our most important disease, stripe rust, it was late developing this season but has become established in California's Central Valley on plots of previously known susceptible varieties and breeding lines. Susceptible varieties showed high stripe rust severity in UC Regional Wheat nurseries in Colusa and Yolo Counties in the Sacramento Valley and in Fresno County in the San Joaquin Valley. To date, no varieties that expressed resistance in 2012 have been affected this season, so no new races of the stripe rust organism with increased virulence have developed.
The stripe rust screening nursery at UC Davis has high levels of disease, but the genotypes in the nursery that carry the stripe rust resistance genes Yr5 and Yr15 are disease-free to date. Some commercial fields of the susceptible variety Joaquin in Kings and Tulare Counties in the San Joaquin Valley suffered high stripe rust severity, as reported by UCCE Tulare County Farm Advisor Steve Wright. Disease became severe in late April, particularly in fields of Joaquin that were not treated in a timely manner with effective fungicides.
Regarding other disease and pest incidences this season, the aphid-transmitted barley yellow dwarf virus (BYD) is present throughout the Central Valley and surrounding areas. Overall incidence and severity is relatively low, and yield impact will be minor. I detected a severe infestation of the Russian wheat aphid in one corner of the UC Regional Wheat nursery in Clarksburg (Yolo County). Russian wheat aphid infestations can commonly develop if the crop is drought-stressed. One final disease of note is Bacterial leaf streak (Xanthomonas spp.). I detected moderately severe levels of disease on several common wheat and durum varieties in the UC Regional Wheat nursery at the J.G. Boswell Buena Vista Ranch in Kern county; yield impact will be minimal.
Jorge Dubcovsky Elected to National Academy of Sciences
Jorge Dubcovsky, the internationally acclaimed wheat geneticist at the University of California, Davis, has been elected to the National Academy of Sciences, one of the highest honors bestowed on scientists and engineers in the United States. This is the latest in a long string of honors awarded to Jorge.
"California wheat growers are extremely fortunate to have Jorge leading the wheat breeding program at UC Davis," said Larry Hunn, Chairman of the California Wheat Commission. "Jorge keeps the needs of our growers at the top of his list; he has always been very responsive to our suggestions."
UC Davis Field Day on May 15
The wheat industry will be gathering in Davis on May 15 to tour the small grains research trials and discuss various crop production issues in related to cereal grains, including advances in quality and yield, pest and disease updates, and weed control. The meeting will start at 8am at the UC Foundation Seed warehouse on Hutchison Road west of Highway 113. Lunch will be served at noon and the forage and alfalfa field day will take place in the afternoon.
Of special interest will be the dedication of the new UC plot combine, purchased with funds from both industry and UC Davis. The harvester will be dedicated to the memory of Mike Bouris, a long-time California Wheat Commissioner. Mike participated in the California wheat industry at many levels, including being a member of the CWC since 1987, serving as President of the California Association of Wheat Growers, and being a founding member of the board of the California Grain Foundation. He was also active in national wheat organizations and often went to Washington, DC to discuss issues of concern with members of the California Congressional Delegation. Anyone lucky enough to have visited Mike's farm in Riverside County for a tour of his equipment "museum" will understand how appropriate this dedication is.
Kings/Tulare Field Day a Success
UC Farm Advisor Steve Wright organized a well attended field day on April 30, starting at the Milky Way Dairy in Visalia and continuing to the Westside Research and Extension Station in Five Points.
Attendees heard from a variety of speakers, including Lee Jackson (above), wheat breeder Alicia del Blanco, and Farm Advisors Brian Marsh, Bob Hutmacher and Steve Wright, who discussed their California Wheat Commission-supported field research projects. Topics included disease resistance, salinity tolerance, weed control, and nitrogen use efficiency. Private breeding companies discussed their current varieties available in the California market. Durum, common wheat, and barley variety trials were all on display.
2013 Harvest
The wheat harvest will begin soon in the Imperial Valley and move north. With the dry and windy weather experienced in late April, harvest is expected to be on the early side. As usual, the Commission will be collecting variety samples around the state and testing the quality of this year's crop.
