Sustainability

2020 Ground Work: Soybean Breeding in Arkansas

Because soybean planting was late this season, we have just reached the beginning of the 3- or 4-week window we have to crossbreed soybeans for our Eagle Seed Company breeding program. Crossbreeding is how we develop new soybean varieties.

All winter, my wife and I carefully planned all the crosses we want to make this season from the combination of genetics we own and the genetics we have from research programs and other sources. We focus on a wide variety of soybeans, including food-grade varieties, and we plan crosses as efforts to combine or improve desirable genetic characteristics like hilum color, soybean size, yield, and more.

The source, or parent, varieties were planted in what we call our “nursery” with timing that ensures that regardless of the maturity group, the soybeans we want to cross should be flowering at the same time. That often means we planted the same variety at different times.

And now, as the soybeans start flowering, we hand-pollinate each cross we planned, with careful labeling and record-keeping so we can track our work. We’ve learned that hand-pollination works best in bright sun, as the pollen sticks better on sunny days. So, we typically pollinate from 9 a.m. to about 1 p.m. every day, 7 days a week, during these few weeks.

First, we carefully collect fully open, developed flowers from the donor plant and store them in containers that we can carry to the “mother” plants. Then, we take a low seat between the rows of parent plants (usually under an umbrella – it gets hot out here). Using tweezers with a needle-like tip, we gently dissect a flower bud on the mother plant, taking off the sepals, or leaf-like pieces at the base of the flowers. We also remove the stamen, the part of the flower that makes pollen. We leave the stigma, which sticks up from the center of the flower. Then, we gently rub the donor flower over the stigma, to provide pollen from the other parent. We remove all other flowers on that node, or branch, of the soybean plant to ensure that’s the only pollination occurring here. Then we carefully tag the plant with the cross that has been made. Our tags have to be weather-proof so we know what we have when we harvest individual pods in a few weeks.

We inspect the plants over the next few days to see if the cross was successful, and we make countless crosses because soybean plants naturally don’t support all their flowers becoming pods. Next to the new crosses, we have plots containing the crosses we made last year. Then plots contain crosses from 2 years ago, and so forth. It takes about 7 years for seed for a new variety to be pure enough to use commercially. Throughout each generation, we are constantly evaluating the soybeans for the best characteristics for our area and our customers, so that we bring forward just the top new varieties we’ve created. That’s why recordkeeping is critical.

Eagle Seed Company is truly a family business. My father-in-law was a plant breeder, my wife is a plant breeder, and we’ve had our niece join us in pollination. She will go to college soon, but we’ve encouraged her interest in the business.

And we grow the soybean varieties we develop. As I’ve mentioned before, all of our soybean fields outside our research plots are grown first to be seed we sell to other farmers. All our soybeans have reached full canopy, so we are done with weed control for the season.

However, we plan to make a fungicide application when the soybeans reach the R3 stage, and pods have started forming. We’ve found that today’s fungicides protect from diseases like frogeye leaf spot and cercospora leaf blight, and they also support plant health. Soybeans treated with a fungicide at this stage have a higher germination rate and fewer damaged soybeans after harvest. Because we are growing seed for other farmers to plant next year, that’s important.

We also scout for insects like stinkbugs and pod worms. If infestations reach an economic threshold, we will include an insecticide with our fungicide application, but we don’t often need to do that.

It’s been dry for a couple weeks, so we have been irrigating our soybeans, as well. My son Cody manages our irrigation, and this year we’ve added new technology to use our water more efficiently. We have soil moisture meters in our fields that send wireless signals to help us monitor conditions in each field. We also have software connected to each of our groundwells to show their output. Cody has an app on his phone that allows him to see all this data and turn pumps on and off more quickly than when we depend on physically checking each field. This is especially useful when we do get heavy rains, often from tropical systems, after weeks of dry weather. The technology is one way we are continuously improving our sustainability.

Our rice is starting to head out, meaning the main stalks that will develop grains of rice are emerging from the leaves. We completed our in-season nitrogen application a few weeks ago, aerially applying a form of nitrogen to our flooded rice fields. We will keep water on those fields through the end of August, but we continuously monitor the fields to maintain water levels. Our hot weather has allowed quite a bit of evaporation recently.

Between our soybean breeding program, irrigation and managing our main crops, we’ve got plenty of work to do.

 

Brad Doyle
Brad Doyle

U.S. Soybean Farmer

Arkansas

Brad Doyle and his wife Joyce farm and breed and sell soybean seed in Arkansas, in the south-central U.S.