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PhytoGen has Roundup Ready gene for Pima

PhytoGen Cottonseed's breeding program is the only one to isolate the Roundup Ready gene for Pima, company sources said during a recent series of field meetings in California's San Joaquin Valley from Bakersfield to Dos Palos.

Research agronomist Scott Bordelon, in charge of PhytoGen seed production in California and the Mid-South, made the comment during a tour of grower Bob Wilson's fields near Huron.

Bordelon said they achieved, after attempts starting in 1996, isolation of the gene, a task more difficult in Pima than in Acala, and now have lines progressing toward availability of some seed in 2004.

“As far as I know, we are the only company to have isolated the Roundup-Ready trait in Pima. The big obstacle in breeding was Pima sometimes rejects the Acala chromosomes carrying the trait. But now it's been tested in five generations and maintained 100 percent of the trait. We are very excited about that,” he said.

PhytoGen, he added, is also advancing a Roundup Ready version of its PHY 78 Acala and hopes to have some seed of it available in 2004, anticipating a wide-scale, commercial launch the following season.

2005 approval?

In presenting the test plots of the company's Pima lineup, Bordelon said PhytoGen's experimental PHX 609, in its first year of screening by the San Joaquin Valley Cotton Board, has potential for approval by 2005.

He said while their PHY 76 Pima is already an excellent performer across much of the valley, they are looking for improvements to it with their nearly identical, sister lines, PHX 601 and PHX 600.

Having demonstrated high fiber-traits, both are mid- to full-maturity types. The one that shows the highest yield, at least 3 percent more than PHY 76, in trials will go for further development.

Although it was in short supply this year, more PHY 76 seed will be available for the 2003 season. The variety was planted to about 125,000 acres in the valley this year.

PHX 101, an early to mid-maturing Pima selection in its second year of SJVCB testing, has yield comparable to PHY 76, but it is earlier and its fiber length in one trial was 1.44.

PHX 612, known for its lighter-colored leaves, is in its first year of testing. Its earliness is equal to or slightly more than PHX 101, and its fiber quality is equal or superior to PHY 76.

Companion variety

“Early pima cotton is an untapped market here,” Bordelon said. “We've focused a lot of our development on early Pimas that have exceptional fiber qualities. Our PHX 101 and PHX 612 fit an early- to mid-maturity class and maintain or improve on fiber quality.”

Pointing to the Acala test plots, he said their PHY 78 is not considered a replacement but a companion to PHY 72 and both will remain available. PHY 78, with its tighter bolls, performs better, with a 5 percent to 7 percent higher yield than PHY 72, on the soils of the valley's West Side and the Dos Palos area to the north.

Earliness is about the same for both varieties. PHY 78, while not a columnar type, is a bit taller and sets more top crop, and PHY 72 tends to put on more branches and has lower fruiting positions. PHY 72 has a fiber length of about 1.20 to 1.21, and PHY 78 runs about 1.19, in comparison to the valley standard, Maxxa, at 1.15 to 1.16.

He said PHY 78 bolls in seed fields are showing nine to 10 seeds per lock, vs. the typical seven to eight seeds per lock.

PhytoGen 78 was approved in March for introduction this season, and although seed was limited, PhytoGen anticipates having ample supplies available next year.

Bordelon said they don't believe in a yield plateau of three to three-and-a-half bales for the valley and they continue to test lines showing promise of more yield. Those show a 5 to 6 percent increase over PHY 78, which scored 1,551 pounds in the SJVCB trials in 2001, and an 8 percent gain over PHY 72's 1,583 pounds in that same series of trials.

Testing program

PhytoGen has nursery sites on the West Side, near Tulare, and near Corcoran, according to Bordelon. “We breed for varieties that are adapted for the West Side, then test them at four valley locations, and finally test them at 10 or 12 locations across the valley. So, by the time we introduce a variety, it's been tested everywhere.”

On other fronts for improved cotton, he said PhytoGen varieties having resistance to piercing and sucking insects are expected by the end of the decade.

They also are progressing with a pair of Bt genes for worm control in an experimental having PHY 78 background. In West Side trials they have found no worms surviving later than the second instar. Four days later, the worms were dying off, and the trial plot did not have to be treated with any insecticide for worms. The company's testing aims at quantifying what value this resistance will have for growers.

Although instructions to seed companies for use of Monsanto's advanced “Roundup Ready Flex” technology are still to be released, Bordelon said he believes, on the basis of trials in the Mid-South, that the herbicide can be sprayed after the fourth true-leaf, perhaps up to canopy closure. The technology still must clear EPA registration, which Monsanto anticipates in 2006.

“Every seed company will have the technology at the same time. Depending on delivery, we introduce it in our greenhouses in November in several of our elite lines, including PHY 78 and our experimentals following it,” he said.

PhytoGen breeder Joel Mahill noted that the company is searching for desirable yield and fiber traits in diverse, wild cotton germplasm from throughout the world and the process from initial crosses to commercial availability of seed can consume 12 years.

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