Subtropical Fruit Crops Research & Education
University of California
Subtropical Fruit Crops Research & Education

Posts Tagged: citrus

How Wierd Can Lemons Get?

In a recent post about lemon shape being affected by high temperatures 

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=29443

a grower sent an image of what I thought was  a blurred view of something that was circled.  I responded saying that I couldn't make it out, and a better image should be sent.

The grower resent the image, but this time it was about the long yellow thing in the background that was being asked about.  The tree is planted next to a chile pepper plant and the question was whether the shape was affected by the chile proximity.

The grower had never seen anything like it before and I haven't either.  But rack it up to the high temperature wave during flowering and the rapid fruit growth period and hormones gone amuck.  if temperature extremes become more common, unusual fruit shapes will likely become more common.

 

Posted on Friday, March 22, 2019 at 7:43 AM
Tags: citrus (302), climate change (4), hormones (1), lemon (93)

Why is Lemon Sour?

Now we know

A team of researchers, including two from the University of California, Riverside, has identified the genes responsible for the hallmark sour taste of many citrus fruits. Published Tuesday, Feb. 25 in Nature Communications, the research could help plant breeders develop new, sweeter varieties.

Modern citrus varieties have been bred over thousands of years to generate a broad palette of sour and sweet-tasting fruits. Analyses of their pulp reveals that a single chemical element--hydrogen--is largely responsible for the difference between sour and sweet-tasting varieties, which usually have similar sugar content. The pulp from sour fruits contains more hydrogen ions, giving it a lower pH and a tangy taste that is recognized by acid-sensitive cells in our taste buds. Conversely, pulp from sweeter varieties contains fewer hydrogen ions and tastes less acidic.

Ronald Koes and colleagues at the University of Amsterdam in the Netherlands set out to untangle how some citrus varieties wind up with more acidic juice than others, a process that until now has remained a mystery. Their interest stemmed from a previous study showing that higher acidity in purple petunia flowers resulted in more petal pigmentation.

Intrigued by the Faris variety of lemon tree, which produces branches bearing both sweet and sour fruits, and white and purple-tinged flowers, Koes' team turned to UCR plant scientists Mikeal Roose and Claire Federici. Using the university's vast Citrus Variety Collection, which preserves over 1,000 living citrus and related fruit varieties, Roose and Federici selected the Faris lemon and 20 other citrus fruits ranging from wincingly sour to sugary sweet for Koes' team to analyze.

By studying the expression of genes related to those controlling acidity in petunias, Koes' team identified two citrus genes, CitPH1 and CitPH5, that are highly expressed in sour varieties and weakly expressed in sweet-tasting varieties. The CitPH1 and CitPH5 genes encode transporter proteins that pump hydrogen ions into the vacuole, a large storage compartment inside juice cells, thus increasing their overall acidity.

Next, the team turned its attention to genes that control the levels of CitPH1 and CitPH5 in juice cells. While down-regulation of CitPH1 and CitPH5 in sweeter tasting varieties arose multiple times independently in different varieties, the researchers found that mutations in genes for a handful of transcription factors (proteins that help turn specific genes on and off) were responsible for reduced expression of CitPH1 and CitPH5, and therefore a sweeter taste.

Roose, a professor of genetics in UCR's College of Natural and Agricultural Sciences, said the findings could help breeders develop better-tasting citrus fruits. However, he said breeding varieties with severe mutations in the transcription factors such as those studied in the "acidless" citrus would be "overkill," producing sugary citrus fruits with none of their popular acidic kick. Instead, plant scientists should look to target mutations that have a less dramatic effect on the production and activity of transporter proteins.

"By understanding the mechanism acidification of fruit cells, we can now look for related genes that might reduce the expression of CitPH1 and CitPH5 just enough to engineer or select for new, sweeter varieties," Roose said.

 

Hyperacidification of Citrus fruits by a vacuolar

               proton-pumping P-ATPase complex

Nature Communicationsvolume 10, Article number: 744 (2019)

https://www.nature.com/articles/s41467-019-08516-3

lemons with some nipples
lemons with some nipples

Posted on Wednesday, March 20, 2019 at 8:41 AM
Tags: acidity (3), citrus (302), lemons (9)

World Citrus News

There's so much gloom about the fate of citrus in Florida and California, but in spite of that talk, world citrus production is increasing.

Global orange production for 2018/19 is forecast to expand 4.2 million tons from the previous year to 51.8 million as favorable weather leads to larger crops in Brazil and the United States. Consequently, fruit for both fresh and processing uses is expected to be greater. Fresh exports are forecast 4 percent higher to 5.1 million tons.

Brazil's production is forecast to rise 13 percent to 17.8 million tons as favorable weather is expected to result in good bloom and fruit set. Fresh orange consumption and exports are flat while oranges for processing are up 2.0 million tons to 12.8 million.

China's production is projected down slightly to 7.2 million on unfavorable weather, resulting in a smaller crop in Jiangxi province. Along with only a small increase in imports, consumption is
lower on overall reduced supplies. South Africa and Egypt are the top two suppliers, accounting for 60 percent of imports.

U.S. production is forecast to recover, jumping 41 percent to 5.0 million tons due to favorable weather. Orange production in Florida has been declining for years due to citrus greening, which has decimated groves and increased costs for crop maintenance.
However, last year, the industry also suffered from damages caused by Hurricane Irma. This year's higher forecast shows a recovery to recent-year levels. Exports, consumption, and fruit for processing are all higher with the larger crop.

Read more about the world citrus industry and get individual country reports generated by the USDA's Foreign Agricultural Service

https://agfstorage.blob.core.windows.net/misc/FP_com/2019/03/04/Florr.pdf

FAS Reports from Overseas Offices The Citrus: World Markets and Trade circular is based on reports from FAS Overseas Posts since December 2018 and on available secondary information. Individual country reports can be obtained on FAS Online at: http://gain.fas.usda.gov/Pages/Default.aspx .

 

citrus cornucopia
citrus cornucopia

Posted on Tuesday, March 12, 2019 at 4:25 PM
Tags: citrus (302), lemons (9), markets (4), production (9)

Citrus? Water? How Do They Go Together?

Advances in Citrus Water Use

                         Workshop & Field Day

Tuesday, March 26, 2019

8 Am - 3 PM

Strathmore, CA

 

Attend the Advances in Citrus Water Use Workshop & Field Day and join UC Davis Irrigation Specialist Daniele Zaccaria as well as other water experts and specialists from the University of California Cooperative Extension, the California Department of Water Resources, and the Citrus Research Board to learn about research advances in water use and irrigation for citrus production. Gain firsthand practical knowledge of the latest developments in the citrus industry and become familiar with methods and tools to measure evapotranspiration (ET) and crop coefficients (Kc), tree water status, and monitor soil moisture to inform irrigation planning and scheduling decisions for citrus. 

 

What to expect?

Session topics include:

  • Current research
  • Water management and regulation
  • Optional Field Session on irrigation technology

View a tentative agenda here.

 

 

Registration Details

 

$35 registration fee includes admission to the field day, coffee, refreshments, and lunch.

 

 

 

Register online, here. Fee will increase on March 13.

 

 

Limited to the first 150 participants

 

 

Logistics and Registration

ANR Program Support, Julia Kalika, (530) 750-1380 or Shannon Martin, (530) 750-1328

citrus cornucopia
citrus cornucopia

Posted on Friday, March 8, 2019 at 1:44 PM
Tags: citrus (302), irrigation (74), water (47)

Water is Life and Watering Citrus is Critical - Come Learn

Advances in Citrus Water Use

               Workshop & Field Day

Tuesday, March 26, 2019

8:00 AM-3:00 PM

Strathmore, California

Register NOW!!!

 https://ucanr.edu/sites/citrusfieldday/Registration/

About the Field Day

 

Attend the Advances in Citrus Water Use Workshop & Field Day and join UC Davis Irrigation Specialist Daniele Zaccaria as well as other water experts and specialists from the University of California Cooperative Extension, the California Department of Water Resources, and the Citrus Research Board to learn about research advances in water use and irrigation for citrus production. Gain firsthand practical knowledge of the latest developments in the citrus industry and become familiar with methods and tools to measure evapotranspiration (ET) and crop coefficients (Kc), tree water status, and monitor soil moisture to inform irrigation planning and scheduling decisions for citrus. 

 

What to expect?

Session topics include:

  • Current research
  • Water management and regulation
  • Optional Field Session on irrigation technology

View a tentative agenda here.

Registration Details

$35 registration fee includes admission to the field day, coffee, refreshments, and lunch.

 

Register online, here. Fee will increase on March 13.

 

Limited to the first 150 participants.

Contacts for More Information

 

Logistics and Registration

ANR Program Support, Julia Kalika, (530) 750-1380 or Shannon Martin, (530) 750-1328.

 

Course Content 

Daniele Zaccaria, UC Cooperative Extension Specialist, Agricultural Water Management

 

citrus cornucopia
citrus cornucopia

Posted on Friday, March 8, 2019 at 1:26 PM
Tags: citrus (302), field day (4), irrigation (74), water (47)

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