Cotton farmers have a lot of choices when it comes to deciding which seed to plant, said Assistant Area Agricultural Agent Shawna Loper. It is one of the most important decisions they will make during the season.
“There are so many different varieties out there,” she added.
Loper, who is with the University of Arizona’s Cooperative Extension in Pinal, Pima and Maricopa counties, said most farmers in Pinal County grow some form of Bt cotton, which is genetically modified to have one or two genes of a soil bacterium, Bacillus thuringiensis, that creates its own pesticide. Some farmers grow cotton that is resistant to Roundup (glyphosate), so fields can be sprayed for weeds without damaging the crop. A few plant conventional organic cotton.
“There’s just all kinds of seed treatments out there,” Loper said. Varieties vary by season length, seed treatment, yield and resistance to diseases.
Some of the larger seed companies include Monsanto/Deltapine, Dow/PhytoGen, Dyna-Gro, Bayer/Stoneville and Bayer/FiberMax.
“And within the brand names there are also varieties,” she said.
FiberMax has an app, the Bayer CropScience Variety Selector Tool, that farmers can use with their cellphones to select a variety of seed.
The Cooperative Extension conducts variety trials every year around Arizona to help farmers decide which kind of seed they want to plant the following year, Loper said. Trials are going on right now in Stanfield and Eloy, among other places. Each farmer is testing 10 varieties of cotton. Most are new varieties. Some are old standbys. The seed companies decide which varieties they want to enter in the trials.
Loper said the volunteer farmers were chosen because of their skill.
“Usually the people that we pick or who volunteer to work with us are really experienced, knowledgeable, up-to-date — really great cooperators.” he said.
Each farmer plants six rows of each variety in a plot the length of the irrigation run, with 10 plots in each block — and repeats the block three or four times, mixing up the order of the plots.
“For science research we like to have three to four replications of a trial,” Loper said. This allows for human error or small differences in variables.
At the end of the year, they harvest the plots separately, take the yield data and send it to the U.S. Department of Agriculture’s cotton classification office, which sends back fiber quality results.
“We try to have those done as soon as possible,” Loper said. Sometimes it takes until the end of February or early March.
The goal is to have the information available to the farmers when they are ready to buy seed for 2014, so they will have the 2013 results and know which varieties did well in their area.