During a recent field day at Shafter, growers of dry beans in the Southern San Joaquin Valley examined test plots of experimental varieties and learned of developments that might someday help restore production to what is was a nearly a decade ago.
Jeff Ehlers, plant breeder at the University of California, Riverside, said one objective of his trials is to find a robust, tougher replacement to the blackeye standard, CB 46. His trials at the UC Shafter Field Station are supported by the California Dry Bean Advisory Board.
Ideally, a successor variety would have larger seeds but the same or higher yields, while having resistance to cut-out, nematodes, and Fusarium wilt.
Among the most promising lines in comparison to CB 46 are Shafter 49 and Shafter 50, which were in this year’s strip trials at the station. Shafter 49 shows better resistance to root knot nematode and is resistant to Races 3 and 4 of Fusarium. Shafter 50, although it does have a larger seed, and resistance to the nematode, it is resistant to Fusarium Race 3 only.
Ehlers said although previous variety trials have been on 30-inch rows, this year’s plots were planted on 40-inch rows so the difference between the experimentals and CB 46 can be more readily seen.
He said Shafter 49 and 50 have also shown good potential in tests on commercial fields and he hopes they can be put on a fast track for accumulating breeder seed supplies. “That would still mean we are about three years out from actual production.”
Breeder seed, he explained, would have to be developed in isolation with special attention to sanitation before moving on to foundation and certified seed stages.
The variety CB 5 has an been answer in some parts of the San Joaquin Valley to demand for larger seeded blackeyes, but it is susceptible to Race 3 Fusarium, a particular problem for growers in Kern County.
Ehler’s approach has been to “re-create” an equivalent to CB 5 with resistance to the Race 4 Fusarium. Shafter 49 or perhaps another experimental farther along in the process may accomplish that goal.
Complete yield data will be recorded, and production from the strip trials will be used in 10- to 20-acre block trials Ehlers plans to put out next year.
California’s blackeye movement for the 2005 season is estimated at 200,000 hundredweight, while the total shipments of all dry bean varieties in the state is forecast at 1.3 million hundredweight.
In contrast, the state’s 1997 dry bean crop was about 3.2 million hundredweight. The loss of production is attributed to a combination of problems with weather, depressed prices, and acreage shifts to other states.
Bill DeTar, research leader at the station, revealing his observations on subsurface drip irrigation of CB 46, said he found blackeyes have an irrigation crop coefficient about 10 percent greater than that of cotton and send down roots to a depth of five feet much faster than cotton.
His studies confirmed the suspicions of many that blackeyes need more water than cotton.
By the end of the first week in August, DeTar said, the blackeye plot, which was planted May 20, received about 13.5 inches of water. He estimated the stand also mined another 2 inches of water existing in the field.
He said after several years of refinement in using the buried drip system on cotton, the blackeye plot is level in both directions and has a distribution uniformity rating of 96 percent.
Veteran PCA Vern Crawford of Wilbur-Ellis in Shafter reminded growers of black eyes to avoid disrupting the complex of beneficial species.
“In Kern County,” Crawford said, “if you want production, you use mite control, and if you want quality, you use lygus and worm control. But to get lygus and worm control, you risk blowing up mites.”
That’s why, he continued, Temik is a foundation for keeping the number of sprays as few as possible. However, use of Temik has become complicated and its effectiveness is diminished since label changes allow only lower rates on blackeyes.
He said he has been trying to encourage manufacturers to pursue a registration for Agri-Mek or Zephyr for mite control on blackeyes.
Those products, used in tank-mixes with others, would also control leafminers and other pests that pose problems from season to season.
He conceded, however, that manufacturers must invest millions to develop and register new products.
Crawford said Dow Agrosciences’ newly registered Intrepid, with a nearly 20-day activity on blackeyes, will control worms without disrupting beneficial species.
Steve Temple, UC, Davis Extension agronomist, cautioned growers to do their homework to avoid Ascochyta blight if they are considering planting garbanzos this fall.
Bean processors have expressed concern with the disease potential, and meetings are planned to alert growers of the threat in both northern and southern parts of the state.
Good yields and improved prices for the California crop in the 2005 season, coupled with lower production elsewhere in the U.S. and Canada, suggest increased interest this fall in planting garbanzos for harvest in 2006.
Ascochyta can level a garbanzo crop, and he noted that California growers may have relaxed their former vigilance after being spared serious problems with it for many years.
“But this year we saw it in definitely higher amounts in several locations up and down the state,” said Temple, who listed steps to avoid losses to the fungal disease.
First, use only seed from sources you are confident are free of the disease. Seed treatments with commercial fungicides offer a partial, but not complete, degree of protection.
If you see it early in the season, apply Bravo or another registered fungicide as soon as possible. In the Sacramento Valley during the 2005 season, some fields had to be sprayed three times.
And be aware the cropping history of the land you plant to garbanzos. Temple stressed that some growers may be leasing ground that had been planted to garbanzos the last year or two.
“We know from long experience in the Palouse region and other growing areas that the one tried-and-true way to limit the disease is by using garbanzos in a three- to four-year rotation.”
Field sanitation by cleaning up garbanzo crop residue is also critical to the disease host. Temple said outbreaks in California in 1994 and 1996 were traced back to volunteer garbanzos that harbored the fungus between crops.
In California’s Central Valley, Ascochyta flourishes in the spring during alternating wet and warm periods. Its wind-driven spores infect new stands much like wheat rust invades grain fields.
Temple said the disease is economically important to the California garbanzo industry as a whole, since problems with it prevent the Canadian industry from being a stronger competitor with California. The disease is common in all garbanzo growing areas around the world.