“I like to look at several things when I ride the picker with a grower as we harvest a variety test," says Robertson. "Sometimes, the picker has a yield monitor that can give us a close idea of what a variety is yielding, and we can confirm that later at the gin. We can compare the variety we’re picking right now to the one we just picked.”
But, Robertson says, yield is just one component that growers can see from the picker. He also likes to look at plant shape, and how clean a variety picks. “You can tell a lot of things from the seat of the picker,” he says. “I get my best ratings on varieties by doing that.
“For example, I like to see how stormproof varieties are, and how clean they pick. If a variety tends to string out before picking, then it might not be one that waits on me as well as others. I also note how tall the plants are. Some plants grow tall, but they’re more columnar and tend to have less boll rot than other varieties. Some varieties produce big, tall, bushy plants that sometimes don’t pick as clean, and they also tend to have more boll rot, and diseases like target spot if we get behind on PGRs.”
And when he climbs out of the picker seat, Robertson likes to look at certain fiber qualities, such as micronaire. “When you consider the results of field trials, determine the average mic for all the varieties in the test, and then compare it to the micronaire for the varieties that you like,” he says.
“Were they higher than the trial’s average? Lower? Average? If a variety tends to high mic, then it might not be one that waits on me very long to pick. Even if a variety is a high yielder, but I have my pickers stretched really thin, then I know I can’t plant a whole lot of it because it will high mic on me.
“I also like to look at a variety’s leaf grades. Some varieties are hard to stay out of leaf discount, so I put a lot of emphasis on leaf and try to manage accordingly.”
YIELD PAYS THE BILLS
Performance, trait package, availability, seed treatment, and disease package are a few factors to consider in variety selection, says Mississippi State University Extension cotton specialist Darrin Dodds.
Yield still pays the bills, but he quickly notes: so does yield stability. “Some varieties are adaptable to a wide range of soil types and irrigation regimes, and some are soil and/or irrigation regime-specific. A variety that yields high on sandy soil might not do so on mixed ground. We encourage growers to determine where, and under what type of management system, a given variety performs the best, and make sure they plant it in those situations.”
Another factor driving many variety decisions for 2019 is a trait package that includes insect and weed control. Some of that goes back to 2018 and many cotton growers having to spray for bollworms. “If there is a three-gene Bt variety that has a herbicide package that the grower likes, whether it’s Xtend, Enlist, or LibertyLink, that will yield at least as well as what we currently have in a two-gene package, then they will likely move to the three-gene because of instances where we had to spray for bollworms in two-gene cotton this year,” Dodds says.
Availability of new three-gene Bt varieties might be limited in 2019. There were a number of three-gene Bt varieties available in 2018, and more will be available in 2019. If a grower finds a three-gene Bt variety that performs really well on their soil type, he says, availability might be a problem, since seed supply sometimes is an issue in the first year of commercial introduction.
“The herbicide package will also drive variety selection for 2019,” Dodds says. “The majority of Mississippi cotton acres have been planted to dicamba varieties in the past couple of years. However, there are some very good-performing varieties with the Enlist trait package, and we have seen an increase in adoption of these varieties.”
He encourages growers to spend a little time studying a variety’s seed treatment. A base package versus a premium package can mean a substantial difference in cost per bag. “Most seed suppliers offer two-way or three-way combinations of insecticides, fungicides, and/or nematicides. In addition, our growers have been pleased with acephate overtreatments on seed to help with thrips control. After you select your variety, select the seed treatment package that best fits your farm’s needs.”
Finally, consider a variety’s disease package. Dodds urges growers who have fields with a disease history, such as bacterial blight, to select a good-performing variety with the traits that offer at least some level of bacterial blight resistance.
EARLINESS, DISEASE, FIBER QUALITY
University of Tennessee cotton specialist Tyson Raper says several factors that should be considered when selecting a cotton variety include earliness, disease resistance (mainly bacterial blight in the Mid-South), and fiber quality.
“Several recently introduced varieties can be managed to be very early,” he says. “From what I’ve seen over the past two years, I believe a few new varieties may allow us to stretch planting dates into later periods we would traditionally avoid.”
Additionally, disease resistance, particularly to bacterial blight, is becoming more of a concern in the upper Mid-South. “Although we have not recently seen the disease cause widespread yield loss in Tennessee, our only feasible management strategy is selection of a resistant variety,” Raper says.
Cotton growers have seen substantial gains in fiber quality with the introduction of some new varieties from a micronaire and length standpoint. “The impressive part about the gains in fiber quality is they have not come at the expense of yield,” he says. “Many times, the varieties with the better fiber quality properties have performed with, or even better than, other varieties,” Raper says. “Fiber quality is quickly becoming a valuable factor when differentiating between several like varieties.”