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Public Sector Breeders/Geneticists
Explore More Traits

By Carroll Smith
Senior Writer

Seed trait technology in the form of insect and herbicide resistance has provided U.S. cotton producers with useful tools to fight pests and create esoteric values, such as fewer trips across the field and added convenience.

In addition to all of the new and improved technology being explored in these areas, cotton producers have other exciting seed trait technology to look forward to as well.

Todd Campbell, USDA-ARS research geneticist in Florence, S.C., says the primary emphasis of the Pee Dee Research and Education Center breeding program is to develop new germplasm with enhanced traits, such as fiber quality and drought tolerance.

“Like other public sector breeding programs, this is a long-term effort that is essential for broadening the genetic base in cotton and ensuring adequate genetic diversity for years to come,” he notes.

“Private companies use the germplasm that we release here to develop new commercial varieties with all of the characteristics that cotton producers demand.”

In 2007, the Pee Dee breeding program developed and released two cotton germplasm lines that have improved fiber quality, particularly strength and length.

“Seeds of these two lines have been requested by and subsequently provided to private breeding companies devoted to developing commercial varieties,” Campbell says.

Drought-Tolerant Cotton

A seed trait that is of great interest to many cotton producers is drought tolerance. Campbell says the Pee Dee breeding program is initiating field drought and laboratory drought work.

“We are planning a field project designed to screen cotton accessions from the USDA National Cotton Germplasm Collection for their performance under field drought conditions,” he says. “This may identify specific cotton landrace germplasm from Central and South America that contain some level of tolerance to drought. (A land-race cotton variety is an historic, predominant variety that has been grown in a specific area).

“In the future, drought-tolerant germplasm can be used to develop new commercial cotton varieties with drought tolerance,” Campbell adds.

The South Carolina geneticist says they also are initiating research using biotechnology to identify genes that provide drought tolerance in cotton.

On The Texas Front

In Lubbock, Jane Dever, associate professor of cotton breeding at Texas AgriLife Research, lists the biotechnology traits coming on line from commercial companies in three ways: input traits followed by agronomic traits followed by output traits.

“I believe the first wave will still consist of im-proved insect tolerance and herbicide resistance,” she says. “But in what we call the development phase, I think the next new traits will be agronomic traits, such as drought tolerance and nitrogen use efficiency. These are examples of yield enhancement traits that are being field tested in the development stage.”

In looking at the value of drought tolerance, Dever says it sometimes boils down to whether you can grow the same amount of cotton with reduced water. In other words, “What is the value of replacing one irrigation and not reducing your production?”

Another consideration is what kind of yield increase do you see from a normal standard variety that produces well in an area versus one that has been engineered to be drought-tolerant and grown under limited irrigation.

“It has to be something measurable and visible,” Dever says.

Nematode tolerance also is an area in which Dever is involved from a conventional variety development standpoint in collaboration with plant pathologist Terry Wheeler.

“There are sources available for root-knot nematode, but they have not always been in the best performing varieties,” she says. “Root-knot nematode tolerance is difficult to breed for from a field selection standpoint.”

To work around this challenge, the Texas Agrilife Research team modified the breeding methodology and at certain points in the breeding process included excellent greenhouse screening techniques developed by Wheeler.

“We’re developing conventional breeding lines that could be used for breeding commercial varieties or also good enough to go directly into conversion with biotechnology traits,” Dever says. “We are addressing the nematode tolerance goal through classical plant breeding although there still are on-going research efforts looking at biotechnology solutions.

“We’re dealing with three biotechnology genes that will be in the variety anyway, so we try to pack in as much other ‘good stuff’ as we can from a classical breeding standpoint, including our other research objectives in yield improvement, fiber quality, verticillium wilt and seedling disease.”

Thwarting Nematodes/Plant Bugs

Peggy Thaxton, a cotton breeder with Mississippi State University (MSU), along with the rest of the team, also strives to improve fiber quality, develops reniform resistant and nectariless cotton germplasm lines and works with bioengineered cotton.

As for their reniform efforts, the MSU team is working on the development of reniform resistant – not just tolerant – cotton varieties.

“Although this is a major part of our breeding program, we won’t see results from it for a few years down the road,” she says. “2008 was our first year to look at it in the field.”

Another primary focus of the MSU program is developing nectariless cotton germplasm lines to help control plant bugs, which like to feed on nectar found under the leaves and on bolls.

Once these germplasm lines are completed, they are released to commercial seed companies who use them to develop new seed varieties.

As South Carolina’s Todd Campbell says, “The public sector is more in-volved in broadening the genetic base and improving specific characteristics to help private industry develop a finished variety that has all of the traits that a producer would like to have.”

Contact Carroll Smith at (901) 767-4020 or csmith@onegrower.com.

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