California blackeye bean growers may have something to look forward to in the new, experimental cultivar, UCR 539, and other recent research developments, according to Jeff Ehlers, plant breeder at the University of California, Riverside.
“Across different environments, UCR 539 yields in most cases are head-to-head with CB46, so we have a reasonable amount of confidence that UCR 539 is a good-yielding variety,” Ehlers told bean growers recently in Bakersfield.
In trials at the Kearney Research and Extension Center at Parlier in 2003, UCR 539 yielded 52 hundredweight per acre, statistically the same as CB46, the California industry's standard.
CB46 is resistant to race 3 Fusarium wilt and the rootknot-nematode complex, but UCR 539 carries resistance to both races 3 and 4 of Fusarium wilt as well as the nematode resistance.
Although race 4 Fusarium is not thought to be widespread in California, Ehlers noted it has been identified in several locations from Madera County to Tulare County and resistance to it is a good precaution.
UCR 539 has a desirable non-vining growth habit like the variety CB27 (released by the California Crop Improvement Association in 1999) but a larger stature and larger, whiter seeds. It will be further evaluated in strip trials this year.
Progress in breeding for lygus resistance was also demonstrated in Ehler's 2003 screening trials. “We got promising results from old-fashioned field selection, recombining, and selecting again. It looks like it is working.”
At the Kearney center, Ehlers and his colleagues compared lygus damage on CB46, CB27, several experimental lines under development at UCR, and four lines developed from beans native to Africa. The African lines were selected from hundreds of lines collected from throughout the world.
All plants were grown without insecticide treatments other than Bt applied for worms.
Two African lines showed about 35 percent lygus-damaged seed, significantly less than the 45 percent damage to CB46 and even higher damage to other entrants. The other two African lines, which did not flower until after lygus pressure subsided, were deleted in the results.
May, June seedings
Half the plots were seeded in May and half in June in preparation for expected peaks of lygus activity. All plants were hand-harvested 85 days after planting to eliminate their natural recovery effects, or secondary flush, after the first set of pods was damaged by lygus.
Researchers, Ehlers said, suspect the key to resistance to lygus is in finding plants having a compound that inhibits the digestive enzymes injected by the sucking insects as they feed.
As a way to expand markets for California blackeyes, Ehlers said, growers may want to consider the traditional diets of the southeastern U.S.
Frozen blackeyes offer the advantage of a quicker, more convenient way than soaking dry beans for use in dishes common to the region.
Southeastern growers, who farm about 40,000 acres of blackeyes and other cowpea-type beans, have changed from fresh harvesting to dry harvesting because high-moisture, fresh beans had to be processed immediately and involved considerable harvesting expense and product spoilage.
Dry beans, on the other hand, can be harvested, stored, soaked in water, blended with fresh vegetables, and sold in frozen or canned form.
According to American Frozen Food Institute statistics, annual production in the southeast of cowpeas for dry, soaked, and then frozen use is about 30 million pounds, or about 180,000 hundredweight in dry grain beans.
Ehlers said many in the frozen food industry predict persistent-green-types will gradually displace common cowpeas in frozen products.
“The southeastern industry's shift to a dry product gives California growers an opportunity for a larger market. We can produce better quality without the rain, humidity, and insect pressure of the southeast, and we are already accustomed to dry harvesting.”
He said a goal of UCR breeders is to come up with high-yielding varieties designed for that market. Attractive possibilities for this purpose might be new varieties from the green-colored, all-white, or brown breeding lines of cowpeas now in the breeding program.
The economic advantage of processed dry beans, Ehlers added, is they are sold as a profitable, high-demand vegetable product but are grown and handled under the lower cost-structure of an agronomic crop.
All-white types may also have potential for processing into flours for new value-added products.
Another speaker at the meeting, Carol Frate, Tulare County farm advisor, said nutsedges remain the toughest weeds for blackeye beans. “You can't expect to get rid of them in one crop in one year. It takes several years.”
Although growers can take some steps now to perhaps better manage the weeds, she said prospects for new herbicides are pending California registrations.
“When blackeyes are just coming up, nutsedges, particularly purple nutsedge, can be really competitive for water, and later in the season, if the crop is stunted for one reason or another, nutsedges can overgrow the blackeyes and carpet a field.”
Often growers avoid blackeyes for fear that the weeds will overtake the beans and infest succeeding crops as well.
So what can be done?
“Sometimes very close cultivation — refined perhaps with GPS — on good soil and with timely irrigation can help blackeyes get big enough where they can be good competitors with nutsedges.”
Dual, or Lasso, in counties where it is permitted, can suppress yellow nutsedge early in the season, but they don't control purple nutsedge.
Herbicides applied in other crops rotated with blackeyes may reduce nutsedge pressure, but, she added, “They aren't slam-dunks.” In alfalfa, Zorial provides some control but not for the entire season. Eptam, if applied timely and repeatedly, will suppress the weeds. In cotton and corn, Roundup Ready varieties can help.
Not yet registered for dry beans in California, Gowan Co.'s Sandea controls both species of nutsedges and certain broadleaf weeds, but lambsquarter and grasses escape it. Frate said when it does become registered for California dry beans, it will likely be for postemergence, directed-spray use.
Based on her experiences with Sandea in her trials in 2001 and 2003, she said, “It probably won't be cheap once it is registered, but it can be another tool to continue the battle with nutsedges.”
Frate said she is interested in evaluating BASF's Outlook, the selective, pre-emergence herbicide formerly known as Frontier.
It has a federal registration on dry beans, but it does not include blackeyes, she said. “We will have to see if we have problems with that. It gets some annual broadleaf weeds and some grasses, and the federal label mentions yellow nutsedge but not purple nutsedge.”