Variety selection is one of the most important decisions for modern cotton farmers in the Rolling Plains of North Texas, Oklahoma and Kansas, says an Oklahoma State University agronomist.
"Selecting productive cotton varieties is not an easy task, especially in Oklahoma where weather can literally make or break a crop,” says Dr. Randy Boman, Oklahoma State University Research Director and Cotton Extension Program Leader located at the OSU Southwest Research and Extension Center near Altus, Okla.
“Producers need to do their homework by comparing characteristics of many different varieties and then key these attributes to typical growing conditions,” he says.
Boman says growers can't control growing conditions from year to year, but they can select varieties based on desired attributes. “It is very important to select and plant varieties that fit specific fields on your operation. Don't plant the farm to a single variety but try relatively small acreages of new ones before extensive planting.
He recommends multi-year and multi-site performance averages when available to evaluate prospective varieties. “However, due to the rate of varietal release, many new varieties have not undergone multi-year university testing or perhaps no university testing at all.”
Results from last year’s variety trials, which were “gutted by the Great Drought, are available in the 2011 Extension Cotton Project Annual Report available at the NTOK Cotton (www.ntokcotton.org) website.
“Because of the tough year in 2011, it will be important to investigate variety performance in prior years,” Boman says. Results from 2010, for instance, include summaries for dryland and irrigated locations. “This is an excellent resource and provides much information on variety performance, including yield, lint turnout and fiber quality. Individual site data as well as the nine-location means for dryland and the seven location means for irrigated sites are included.”
Boman says Oklahoma cotton growers should consider several factors when selecting varieties.
Relative maturity rankings (provided by seed companies) will be beneficial. “Don't expect a full-season cotton variety to perform well in a short-season environment where an early or early-mid maturity variety might work best. Longer-season varieties will typically do much better when planted earlier and then provided an excellent finish. In recent years these have performed well in many dryland situations in the southwestern corner of the state.”
Early-mid maturity varieties may be better for later plantings, and for late plantings or replant situations, early maturity varieties may be a better option.
Yield is top factor
"Yield potential is probably the single most important agronomic characteristic because pounds drive profitability and provide the safety net of higher actual production history (APH) in case of catastrophic loss. This crop insurance perspective is important in our high risk area.”
He says yield stability across environments is also important. “We want to find a variety that can provide high yield across varying water inputs.
Producers should also consider lint quality. “We have made a lot of progress in fiber quality over the last several years. Fiber length, also referred to as staple, is generally good to excellent for most new varieties. A lot of factors—overall environment; planting date; variety; early season fruit loss with later compensation; excessive late season irrigation or rainfall; seedling disease; early seasons setbacks due to hail damage, blowing sand, thrips and other factors—can affect crop micronaire, an indirect measure of fiber maturity and fineness.
“Fiber strength has also significantly improved and many newer varieties tend to be a least 30grams per tex. Length uniformity can be affected by staple, maturity, field weathering, and harvest method.”
Boman says picker harvested cotton quality is typically higher than stripper harvested cotton. “Higher maturity fiber generally results in better uniformity. Leaf grade can be affected by density of leaf hairs on specific varieties in some years. Generally, cool, wet fall conditions can lead to lower quality leaf grades for varieties that tend to be hairy. In drier harvesting environments these differences tend to diminish.”
Color grades depend primarily on field weathering or exposure of the mature fiber to warm, wet conditions. “The highest quality a cotton boll can have is on the day it opens,” Boman says. “After that, if conditions favor microbial growth (warm, wet conditions) or if an early freeze affects immature, unopened cotton, then color grade quality will likely be reduced.”
Environmental conditions also influence bark. "Bark contamination is generally driven by significant late season rainfall followed by a freeze. In some years, this can't be easily managed if stripper harvested. Conversely, picker harvesting can significantly reduce or eliminate bark contamination.
“Storm resistance is still a concern for growers in our area. Even though many producers have adopted cotton varieties with less storm resistance over the last several years and have generally done well with those, the producer’s overall management system can be important. Under significant moisture stress on dryland, some newer varieties may provide an unacceptable level of storm resistance, especially if the field is left to the freeze.”
Some producers may select varieties with less storm resistance if they improve harvest preparation. “Producers planning to execute a sound harvest aid program as soon as the crop is mature can probably grow some fields of less storm resistant cotton,” Boman says. “However, having large acreages of varieties with low storm resistance might be a prescription for disaster if the right environmental conditions align near harvest. Do not plan to leave low storm resistance varieties in the field until a freeze conditions the plants for harvest. Unacceptable pre-harvest lint loss is likely to result.”
He says higher storm resistance varieties are better adapted to Oklahoma harvesting conditions and are more likely to survive damaging weather prior to harvest without considerable lint loss. “Inquire about the storm resistance of any variety on your potential planting list. If you choose a variety with low storm resistance, plan and budget for a good harvest aid program that will let you achieve an early harvest.”
Look at traits
Boman says cotton farmers need to look carefully at transgenic traits and determine which ones best suit their production program.
“Ask which herbicide-tolerant trait do I need? Weed control has been catapulted forward by the advent of transgenic Roundup Ready Flex and GlyTol, both of which provide excellent glyphosate tolerance.
“Liberty Link technology adds glufosinate tolerance, and now some GlyTol plus Liberty Link (stacked) cotton varieties are available. The agronomic capabilities of glyphosate tolerant cotton varieties continue to improve and the weed control system is very effective if properly executed. The Liberty Link system has thus far been more widely adopted in other regions because of weed control considerations. The widely anticipated GlyTol, the proprietary glyphosate tolerant trait from Bayer CropScience, has been approved by regulatory agencies and has been launched.”
Insect resistance is another important consideration in variety selection. “Bollgard II and Widestrike have provided outstanding caterpillar pest control,” Boman says. “These technologies have been widely planted on Oklahoma cotton acres. Because of the lack of disruption of beneficial arthropod populations by insecticides used to target bollworms and other caterpillar insects, aphids likely will not be flared, which is of considerable value.”
Boman says cost of a particular variety should not be the deciding factor in choosing whether to plant it. “But it is important. The value of a high yielding cotton variety with biotech traits to ease management requirements across a large number of acres is a serious consideration. Over the last several years, we have seen significant producer interest in transgenic varieties.”
He says more than 100 varieties from several companies are being sold this year in the region.
Boman recommends the Plains Cotton Growers 2012 Seed Cost Comparison Worksheet as a useful tool in variety selection decisions. PCG developed the Microsoft Excel spreadsheet, which can be used within a Web browser or downloaded and saved to a computer.
“Oklahoma is in the same seed/technology pricing zone as the Texas High Plains. Nearly all of the commercial varieties available in our region are listed.
“Users may select up to nine varieties to simultaneously compare total seed and technology fee costs based on a specific seeding rate. The user enters the row spacing and seed per row-foot and the spreadsheet calculates the seed drop rate on a per acre basis. Cost per acre is automatically calculated based on published pricing for the various seed varieties and technology fees.”
The 2012 Plains Cotton Growers Seed Cost Calculator Excel Worksheet is available at www.plainscotton.org.
NTOK Cotton is a cotton industry partnership, which supports and encourages increased cotton production in the Rolling Plains of North Texas, Oklahoma and Kansas. For more information on the cotton scene, see ntokcotton.org and okiecotton.org. For questions or comments on Talkin' Cotton, contact firstname.lastname@example.org.