Posts Tagged: Oranges
Sweet Mother Orange Tree released from quarantine
The 1000th tree okayed for growing by California's Citrus Clonal Protection Program happens to be the oldest living orange variety in the state.
The program, housed at UC Riverside, is the first of its kind in the world. It began in the 1950s, and its scientists spend up to three years testing and clearing citrus trees of disease so they can be released to commercial and private growers.
By law, every citrus tree newly propagated in California can be traced back to one mother tree created at UCR through the protection program. Program Director Georgios Vidalakis and his group begin their process by testing incoming trees for more than 30 citrus diseases, whether the diseases are known to have emerged in the state or not.
The treatment for any disease identified in that first round of testing is to make a new mini tree from a few cells of the original budwood — short, leafless twigs with buds meant for propagation. “We use special plant cells for this process that diseases cannot penetrate,” Vidalakis said.
After the mini tree grows large enough, program scientists go back and do a second round of testing for disease, making sure they picked the right cells for propagation and eliminating any prior trace of illness.
If it passes the arduous second set of tests, the new tree gets a variety index or VI number that accompanies it for the rest of its life, and it is released to the public.
Dubbed the Mother Orange Tree, Bidwell's Bar is a sweet Mediterranean orange brought to California from Mazatlán, Mexico, and planted in 1856. It was first planted near the Bidwell Bar Bridge near Oroville, then dug up and replanted twice.
Its survival skills are some of the reasons Tom Delfino, former California Citrus Nursery Society director, recommended the old orange tree for the protection program.
“Apparently this variety is very rugged,” Delfino said. “Not only has it survived a lot of cold Northern California winters, but the tree has been dug up and replanted twice — once to protect it from impending flood, and again to make way for the Oroville Dam.”
Much of the state's orange industry is based in areas with warm weather. Delfino, who lives in the San Francisco Bay Area, finds citrus an exciting challenge to grow. By suggesting Bidwell's Bar for approval, he was hoping the protection program would clear it so he could buy its budwood.
On the occasions he has visited the original tree, Delfino said the fruit in reaching distance was always gone. “I think it must be tasty because locals grab it for themselves,” he said. “Makes me even more eager to grow and eat my own. I'm extremely pleased the VI testing is completed so I can acquire it.”
Delfino also hopes that this variety will catch on with commercial growers.
“My thought is our citrus industry is concentrated in the southeastern San Joaquin Valley and is subject to a number of pests that like the warm climate there,” Delfino said. “Though this has seeds, which may be a deterrent, it can be grown in colder areas that discourage some of those insects.”
The tree arrived in California nearly two decades before the better-known Washington Navel orange grown by Eliza Tibbets in Riverside. The navel is named for a structure at the bottom end of the fruit, which resembles a belly button. This structure is actually a separate fruit inside the larger fruit. The Washington Navel is also seedless, contributing to its popularity.
“Bidwell's Bar is an example of what was grown in California before the Washington Navel came to dominate, and now that it has a VI number, others can grow it too,” said Tracy Kahn, curator of the Givaudan Citrus Variety Collection at UCR.
Kahn says it's important to preserve the genetic material from a tree with such significance to California. “Some people were worried it was going to die, but now we have an officially cleared source of this historic tree, and it is protected for future generations,” Kahn said./h3>
A new study outlining the costs and returns of establishing and producing navel oranges with low-volume irrigation in the southern San Joaquin Valley has been released by UC Agriculture and Natural Resources, UC Cooperative Extension and the UC Davis Department of Agricultural and Resource Economics.
“A cost study gives a ‘new' grower a better idea of all the costs that are involved with producing the crop,” said co-author Greg Douhan, UC Cooperative Extension citrus advisor for Tulare and Fresno counties.
Real estate agents, land leasers, bankers evaluating loan applications and others can use the cost study to estimate current costs to plant and produce oranges and expected profits.
This study updates an earlier version, using as an example the Cara Cara navel, which is known for its distinctive pink-colored flesh rather than the conventional orange flesh of the Washington navel.
“The Cara Cara has been returning very good prices to growers for the past decade or so and is a relatively new navel,” said co-author Craig Kallsen, UC Cooperative Extension farm advisor in Kern County. “Of course, grower returns are driven by consumer demand. Why consumers like it so much I do not know, but I suspect it is because it tastes good and is different. You cut it and get a pink surprise. Its harvest maturity is similar to that of the Washington navel.”
The updated version takes into consideration “things like inflation, chemical availability, changes in markets both domestic and foreign, governmental regulations and other things,” Kallsen said.
The study is based on a hypothetical farm that consists of 65 contiguous acres onlandin the San Joaquin Valley previously planted to another tree crop. Establishment and production costs are based on 10 acres being planted to oranges. Mature orange trees are grown on 50 acres and the remaining five acres are roads, equipment, shop area and homestead. The grower owns and farms the orchards.
The two major orange varieties grown in the San Joaquin Valley are navels and valencias. Navels are grouped into three types by harvest timing – early, mid and late season. Due to current planting practices, only navels are included in this budget. Cara Cara is the variety of navel oranges currently most commonly planted.
The Cara Cara orange trees are planted double density, 10-by-20-foot spacing, at 218 trees per acre. At this density, it is possible to start harvesting in year 3 or 4. At year 8 or 9, full maturity is achieved and growers begin pruning back every other tree. This allows the grower to maintain yields while at the same time converting the field to 20-by-20 spacing – maximizing yield for a fully mature orchard.
For pest management, the study includes detailed information and links to UC Integrated Pest Management guidelines for citrus. The narrative contains tables of insecticide treatment cycles for establishment and production years.
The section “Exotic Pests of Economic Concern to Citrus Growers” contains information to meet quarantine regulations on exporting oranges from California to countries such as South Korea.
The authors describe the assumptions used to identify current costs for oranges establishment and production, material inputs, cash and non-cash overhead. A ranging analysis table shows profits over a range of prices and yields.
“2021 - Sample Costs to Establish an Orchard and Produce Oranges in the Southern San Joaquin Valley” can be downloaded for free from the UC Davis Department of Agricultural and Resource Economics website at coststudies.ucdavis.edu. Sample cost of production studies for many other commodities are also available for free on the website.
For additional information or an explanation of the calculations used in the studies, refer to the Assumptions section or contact Donald Stewart at (530) 752-4651, firstname.lastname@example.org or Karen Jetter at (530) 792-8255 or email@example.com. To discuss this study with a UC Cooperative Extension farm advisor, contact your local UC Cooperative Extension office: http://ucanr.edu/County_Offices.
This study was funded in part by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award numbers 2017-70016-26755 and 2019-70016-29068.