Posts Tagged: lettuce
When Alejandro Del Pozo-Valdivia started his new job as UC Cooperative Extension entomology advisor in the Salinas Valley last year, he immediately faced an urgent problem in organic lettuce production.
Pest control advisers were finding lettuce aphids in plants that were supposed to be resistant.
Because lettuce aphids crawl deep within the heart of the lettuce head, and because organic growers do not have many options for chemical pest control, the industry relies on patented lettuce varieties that have been conventionally bred to be unpalatable to the pest.
“With other types of aphids, they stay on the outer leaves. When you harvest and clean the head, you are taking the aphids out,” Del Pozo-Valdivia said. “But with the lettuce aphid, it's almost impossible to remove them. We don't want consumers to buy a lettuce with these tiny red insects inside.”
Organic producers pay a premium for resistant seeds to grow lettuce without the lettuce aphid and are mystified by the sudden appearance of the pest inside lettuce heads. Has the aphid developed the capability to feed on resistant varieties? Is there a different lettuce aphid biotype in the area? Since Del Pozo-Valdivia is an entomologist, he is focusing on the pest.
With funding from the California Leafy Green Research Board, Del Pozo-Valdivia and his co-principal investigator, USDA scientist Jim McCreight, have launched a research project to collect and identify the lettuce aphids that are feeding and reproducing in the resistant lettuce in the Salinas Valley.
“I'm asking growers and PCAs to contact me if they find any red aphids in resistant lettuce so we can confirm the type of aphid,” Del Pozo-Valdivia said. “
Seed companies that hold the patent on resistant lettuce also experienced broken resistance in Europe a few years ago, Del Pozo-Valdivia said. They found that the pest in Europe was a different biotype and are already working on identifying genes to maintain the lettuce aphid resistance.
“We haven't seen any scientific report for the U.S. That's why we decided to take the lead. To take the bull by the horns and identify the aphids here in the Salinas Valley,” Del Pozo-Valdivia said.
New studies with sample costs to produce and harvest iceberg lettuce and broccoli for fresh market in Monterey, Santa Cruz and San Benito counties have been released by UC ANR Agricultural Issues Center and UC Cooperative Extension. Vegetable growers may find these useful for estimating their own production costs and potential returns on investment.
“These studies have an expanded section on labor, which includes information on California's new minimum wage and overtime laws,” said Laura Tourte, UC Cooperative Extension farm management advisor in Santa Cruz, Monterey and San Benito counties, who co-authored the study.
Both studies assumes a farm operation of 1,500 non-contiguous acres of rented land. The hypothetical iceberg-lettuce farm has 250 acres planted to iceberg lettuce. The lettuce is hand-harvested into 42-pound cartons containing 24 film-wrapped heads. The hypothetical broccoli farm has 500 acres planted to broccoli. The broccoli is hand-harvested into 21-pound bunch cartons. On each farm, the remaining acreage is assumed to be planted to other cool season vegetable crops.
The authors describe the assumptions used to identify current costs for production material inputs, cash and non-cash overhead. Ranging analysis tables show net profits over a range of prices and yields. Other tables show the monthly cash costs, the costs and returns per acre, hourly equipment costs, and the whole farm annual equipment, investment and business overhead costs.
Free copies of “Sample Costs to Produce and Harvest Iceberg Lettuce in the Central Coast - 2017” and “Sample Costs to Produce and Harvest Broccoli in the Central Coast - 2017” and other sample cost of production studies for many commodities are available. To download the cost studies, visit the UC Davis Department of Agricultural and Resource Economics website at https://coststudies.ucdavis.edu.
The cost and returns studies program is funded by the UC Agricultural Issues Center and UC Cooperative Extension, both of which are part of the UC Division of Agriculture and Natural Resources, and the UC Davis Department of Agricultural and Resource Economics.
For additional information or an explanation of the calculations used in the studies, contact Jeremy Murdock of the Agricultural Issues Center at (530) 752-4651, Richard Smith UC Cooperative Extension advisor in Monterey County, at (831) 759-7357 or Tourte at (831) 763-8005.
How are you celebrating American agriculture in your life? In advance of National Ag Week, March 19-25, and National Ag Day, March 21, Central Valley third-grade students were “learning with lettuce” how to bring more agriculture into their lives last week. The UC Kearney Agricultural Research and Extension Center offers the free lettuce plantings every year at Farm and Nutrition Day in Fresno County and Kings County, typically around the time of National Ag Week.
Students with the help of volunteers learned how to plant tiny lettuce seedlings into a pot of healthy soil to take home for transplanting later. In addition to helping the students connect their food to agriculture, the lettuce planting offered an engaging, hands-on experience growing healthy and nutritious food at home.
National Ag Week is a nationwide effort coordinated by the Agriculture Council of America to tell the vital story of American agriculture and remind citizens that agriculture is a part of all of us. National Ag Day encourages every American to:
• Understand how food and fiber products are produced.
• Appreciate the role agriculture plays in providing safe, abundant and affordable products.
• Value the essential role of agriculture in maintaining a strong economy.
• Acknowledge and consider career opportunities in the agriculture, food and fiber industry.
Each American farmer feeds about 144 people. As the world population soars, there is even greater demand for the food, fiber and renewable resources produced in the United States. Agriculture is this nation's #1 export and incredibly important in sustaining a healthy economy. That's why National Ag Week is a great time to reflect on and be grateful for American agriculture.
The researchers are located at UC Davis; UC Agriculture and Natural Resources Research and Extension Centers; USDA research facilities in Salinas and Beltsville; California State Polytechnic University, Pomona; and the University of Arizona, Tucson.
The UC Davis-led team aims to leverage new technologies to sustain the lettuce supply, despite the challenges posed by climate change.
“We will be exploiting genomic technology to address the needs in all areas up and down the lettuce production chain,” said project leader Richard Michelmore, a plant geneticist and director of the UC Davis Genome Center.
The team's five-year renewable grant, announced recently by USDA's Specialty Crop Research Initiative funding program, was made available through the 2014 Farm Bill.
Research will range from identifying genes that are key to developing important stress-resistance traits in lettuce to fine-tuning imaging technologies that will allow growers to remotely assess the status of their crops in the field. Although grounded in plant genetics and genomics, the project also will delve into a variety of fields that are vital for ensuring sustainable production of lettuce and related leafy greens. Collaborating team members run the gamut in terms of expertise, including plant genetics and breeding, food technology, and agricultural economics.
One of the project's strengths, Michelmore said, is its longstanding collaborative relationship with large and small plant-breeding companies as well as with the California Leafy Greens Research Board, which represents growers of lettuce, spinach and other related crops.
USDA's Specialty Crop Research Initiative, which provided the project's new grant, this year awarded $50 million in grants nationwide for projects ranging from plant genetics research to new product innovation and development of new methods for responding to food safety hazards.
The study also included researchers from Arcadia Biosciences and Acharya N.G. Ranga Agricultural University, India.
The finding is particularly important to the nearly $2 billion lettuce industries of California and Arizona, which together produce more than 90 percent of the nation's lettuce. The study results appear online in the journal The Plant Cell.
"Discovery of the genes will enable plant breeders to develop lettuce varieties that can better germinate and grow to maturity under high temperatures," said the study's lead author Kent Bradford, a professor of plant sciences and director of the UC Davis Seed Biotechnology Center.
"And because this mechanism that inhibits hot-weather germination in lettuce seeds appears to be quite common in many plant species, we suspect that other crops also could be modified to improve their germination," he said. "This could be increasingly important as global temperatures are predicted to rise."
Most lettuce varieties flower in spring or early summer and then drop their seeds -- a trait that is likely linked to their origin in the Mediterranean region, which, like California, characteristically has dry summers. Scientists have observed for years that a built-in dormancy mechanism seems to prevent lettuce seeds from germinating under conditions that would be too hot and dry to sustain growth.
While this naturally occurring inhibition works well in the wild, it is an obstacle to commercial lettuce production.
In the California and Arizona lettuce industries, lettuce seeds are planted somewhere every day of the year -- even in September in the Imperial Valley of California and near Yuma, Ariz., where fall temperatures frequently reach 110 degrees.
In order to jump-start seed germination for a winter crop in these hot climates, lettuce growers have turned to cooling the soil with sprinkler irrigation or priming the seeds to germinate by pre-soaking them at cool temperatures and re-drying them before planting -- methods that are expensive and not always successful.
In the new study, researchers turned to lettuce genetics to better understand the temperature-related mechanisms governing seed germination. They identified a region of chromosome six in a wild ancestor of commercial lettuce varieties that enables seeds to germinate in warm temperatures. When that chromosome region was crossed into cultivated lettuce varieties, those varieties gained the ability to germinate in warm temperatures.
Further genetic mapping studies zeroed in on a specific gene that governs production of a plant hormone called abscisic acid -- known to inhibit seed germination. The newly identified gene "turns on" in most lettuce seeds when the seed is exposed to moisture at warm temperatures, increasing production of abscisic acid. In the wild ancestor that the researchers were studying, however, this gene does not turn on at high temperatures. As a result, abscisic acid is not produced and the seeds can still germinate.
The researchers then demonstrated that they could either "silence" or mutate the germination-inhibiting gene in cultivated lettuce varieties, thus enabling those varieties to germinate and grow even in high temperatures.
Other researchers on the study were: Post-doctoral researcher Heqiang Huo and staff researcher Peetambar Dahal, both of the UC Davis Department of Plant Sciences; Keshavulu Kunusoth of Acharya N.G.
Ranga Agricultural University, India; and Claire McCallum of Arcadia Biosciences, which provided the lettuce lines with variants of the target gene to help confirm the study's findings.
Funding for the study was provided the U.S. Department of Agriculture National Institute of Food and Agriculture and the National Science Foundation.