May 21, 2008

5 Min Read

Choices — cotton farmers now have lots of them. And those choices, especially regarding the varieties they plant, get more complicated every year as new selections become available.

“These are difficult decisions because the options change every year,” says Randy Boman, Extension agronomist with Texas AgriLife Extension Service at Lubbock.

But help is available through data collected from large-scale, limited entry tests conducted by Extension agents and specialists, including Boman, Mark Kelley, and Brent Bean. John Gannaway, cotton breeder with Texas AgriLife Research at Lubbock, conducts smaller plot tests with numerous entries.

Differences that show up among the many varieties tested help producers identify the best options for specific fields.

The Plains Cotton Improvement Program and Texas State Support Committee-Cotton Inc., funded a large-scale, irrigated, moduled test.

“We begin by examining current and historical test results,” Boman says. “Based upon these results and the availability of newly-released varieties, producer-cooperators help us decide which varieties to include in test programs.

“In 2007 we conducted two types of tests under a broad range of growing conditions to evaluate performance and profitability of various cotton varieties.”

Extension agents and specialists studied detailed varietal performance tests on producers’ farms in Parmer, Crosby, and Yoakum counties. Varieties included Roundup Ready Flex, Bollgard II/Roundup Ready Flex stacked, or Widestrike/Roundup Ready Flex stacked.

In-season data included stand count and plant mapping.

Data collected included turnout, bur cotton yield, lint and seed yield, and seed weight per bale. The final report included loan, lint, and total value; ginning, seed and technology costs; and net value. Findings also included pest control and plant growth regulator costs and weather data.

Differences between the highest yielding and lowest yielding variety in each test were 171 pounds per acre, 315 pounds per acre, and 331 pounds per acre for Parmer, Crosby, and Yoakum Counties, respectively; and differences between the variety with the highest net income and the one with the lowest net income per acre were $113, $209, and $201 per acre for Parmer, Crosby, and Yoakum Counties, respectively.

“The best varieties in each test averaged 1,420 pounds per acre and the variety with the best net return averaged $801 per acre.”

Non-moduled tests

Extension conducts several other replicated tests in the High Plains. “We conduct these tests essentially the same as we do the three large-scale, detailed tests, but generally have smaller plots.” Boman says. “Instead of having the cotton ginned at a commercial gin, grab samples, taken from each plot, are ginned at the Texas A&M AgriLife Research and Extension Center at Lubbock, and fiber samples are analyzed at the International Textile Center at Texas Tech University.”

Extension conducted tests at 12 sites in 10 counties. Nine sites were irrigated, and three were dryland. “Yield and quality data from these tests are presented in a similar format as those reported from the three moduled tests except we did not collect growth data,” Boman says.

Differences in lint yield among varieties in irrigated trials ranged from a 198 pounds per acre improvement over the bottom variety at Halfway — to a 528 pounds per acre advantage at Sunray. Differences among varieties in net value ranged from $119 per acre for the best variety at Seminole to $383 per acre for the top at Sunray.

Averages of the highest yielding varieties and the highest net values for top varieties over the nine irrigated tests were 1,645 pounds per acre and $928 per acre.

Boman’s team conducted dryland tests at Lamesa, Plains, and Blanco. Differences among varieties showed a 300 pounds per acre, 285 pounds per acre, and 181 pounds per acre advantage for the best yielding entries for Lamesa, Plains, and Blanco, respectively. Differences in net income for the best varieties were $182 per acre for Lamesa, $169 per acre for Plains, and $124 per acre for Blanco.

The highest lint yields across the three tests averaged 910 pounds per acre and highest net values averaged $514 per acre.

“Differences in yields and net values among varieties in all these tests clearly indicate variety selection is very important,” Boman says.

“The average yields in both irrigated and dryland tests reflect the ‘above average’ growing conditions, and give a good indication of potential yields and fiber qualities that might be expected from varieties.

“We need to remember that 2007 was an excellent year, and many looser picker varieties did not encounter any bad weather during harvest. Although we prefer to see multiple year averages across locations, the rate at which new technologies and varieties containing those technologies are released is ever increasing. We generally don’t see multi-year performance data when many commercial varieties are first sold in the marketplace.

“Also, disease issues are becoming more important and High Plains producers should review data from trials Terry Wheeler and Jason Woodward conducted where significant Fusarium wilt and Verticillium wilt pressure was present. It is important to know which disease may be present in a specific field because the varieties that perform better under Verticillium wilt pressure do not necessarily perform better under Fusarium pressure and vice-versa.”

Small-plot tests

Gannaway conducts variety tests, late-planted variety tests, new varieties and strains tests, Roundup Ready Flex tests, a regional high quality test, a bacterial blight resistance test, a Verticillium wilt resistance test, and a nematode strains test, all grown under irrigation. Wheeler, research plant pathologist, Texas AgriLife Research and Extension Center at Lubbock, makes the bacterial blight, Verticillium wilt, and root-knot nematode ratings.

Gannaway also conducts several dryland variety and Roundup Ready Flex tests.

“From all these tests we determine lint yield, lint loan value, gross loan value, percent turnout, and percent lint. We also ascertain micronaire, length, uniformity, strength and elongation of the lint, leaf index and color grades. We measure boll size, seed index, lint index, and seed per boll,” Gannaway says. He also reports varietal ratings for storm resistance and earliness.

“The results from our 2007 tests showed significant differences among varieties for the characteristics we measured. So producers should study the available research data carefully to help them to choose varieties that best fit their production schemes,” Gannaway says.

“When we accumulate three years or more of data for a group of varieties we calculate comparable lint-yield averages. These averages enable producers to make more realistic yield comparisons among the varieties in a given group.”

Complete results from all these tests are available online at

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