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Posts Tagged: rust

UC development of rust-resistant grain crops bodes well for California and world farmers

The yellow lesions on wheat leaves are a symptom of stripe rust.
Every few years, when weather conditions are just right, California wheat farmers suffer devastating outbreaks of stripe rust, a fungal infection that can rob up to 50 percent of the crop's yield. Rust spores are typically carried on the wind from infected volunteer cereal plants and come to rest on the leaves of wheat, triticale and other cereal crops. The fungi grow just under the plant epidermis and tiny structures penetrate the plant to very harmful effect.

Serious stripe rust epidemics periodically claim the yield of grain growing around the world, including many places where a crop failure can mean widespread hunger in a local population.

Over time, researchers, plant breeders and farmers have found the best way to control stripe rust disease is growing varieties that are genetically resistant to the fungus. However, that strategy posed its own problems. The fungus that causes rust was able to evolve a way around the genetic resistance after only a few years.

“That's the importance of the variety study that we're doing right now,” said Steve Wright, UC Cooperative Extension advisor in Tulare County.

Wright and his colleagues are field testing grain varieties that have been developed by plant geneticist Jorge Dubcovsky, professor in the Department of Plant Sciences at UC Davis.

From 2007 to 2009, the Dubcovsky lab found two different mechanisms of resistance to rust and identified the genes that convey the resistance in the wheat genome. Wheat breeders are now able to use markers established by Dubcovsky to produce wheat selections with rust resistance.

“We're growing these varieties at a site in Corcoran, at the West Side Research and Extension Center, and at a dry land site in Ducor,” Wright said. “The stripe rust resistant varieties are doing very well.”

Since the genes identified by the Dubcovsky lab have been available to plant breeders, “we haven't seen a variety break down as quickly,” Wright said.

Posted on Monday, May 19, 2014 at 2:16 PM
Tags: Steve Wright (0), stripe rust (0)

Not What You Want in Your Drink

Yellowjackets are attracted to this plastic container. (Photo by Kathy Keatley Garvey)

On an outing last Saturday to a Marin County restaurant, we spotted half-filled glasses lining a railing near the picnic tables. As the guests dined...

Yellowjackets are attracted to this plastic container. (Photo by Kathy Keatley Garvey)
Yellowjackets are attracted to this plastic container. (Photo by Kathy Keatley Garvey)

Yellowjackets are attracted to this plastic container. (Photo by Kathy Keatley Garvey)

Close-up of yellow jackets. They soon climbed out and flew away. (Photo by Kathy Keatley Garvey)
Close-up of yellow jackets. They soon climbed out and flew away. (Photo by Kathy Keatley Garvey)

Close-up of yellow jackets. They soon climbed out and flew away. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, August 14, 2013 at 8:00 PM

The Inbetween Time

This is a time when the garden should be calling to me, because it’s that ‘in-between’ time, when the hills are golden–hued with crisping grasses and the ticks are nearly gone, and the apples are ready for picking.  This year my crop of an as-yet-unidentified ‘Delicious’-type variety was bounteous, but since I did not protect against codling moth infestation, and I did not thin the crop, I have too many apples, many of them small, and many of them with an exit hole besmirched with frass.  They are edible, but it’s simpler to just cut the apple in half and find the tunnel from the center and cut out the damage.    I’ve never enjoyed the apples, but they are very flavorful this year.

With the winter rains about to start, I need to clean up the beds.  This involves raking up dead leaves and fallen petals.  I wish I could leave it to rot, and add organic material to my soil.  But this cool, moist mulch would provide a wonderful cradle for fungal infections.   The roses, hollyhocks and peach tree are particularly vulnerable.  The roses are susceptible to black spot and rust, and the hollyhocks, which really don’t belong here in California (but I love their tall stalks and bunches of large open blossoms) develop rust so easily.  Cleaning up fallen leaves is just plain sensible.

As for my peach tree, it is highly susceptible to peach leaf curl.  I will clean up fallen leaves and I’ll be spraying the entire tree with a copper-based fungicide in early December, when all the leaves are gone.  I’ll be mixing up a new batch (or rather my husband will…).  Depending on what I can find, it will be a Bordeaux mixture, or an off-the-shelf product.  Either way, I hope it will work.  I’ll be replacing this tree in the next few years with a resistant variety, because it seems to be a never-ending battle, it is a very old tree and I do love peaches!

Apple hit with coddling moth. (photo by Riva Flexer)
Apple hit with coddling moth. (photo by Riva Flexer)

apple with coddling moth 'stings'

Posted on Monday, November 21, 2011 at 11:50 AM
Tags: apples (6), fallen leaves (1), fungicide (1), hollyhocks (1), peach (2), rust (1)
 
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