It’s been a trying year for researchers in general in terms of collecting good data, according to LSU AgCenter plant breeder Stephen Harrison of the School of Plant, Soil and Environmental Sciences.
Working around rainfall and putting in long hours have paid off with excellent breeding program progress and advancement of superior breeding lines.
The breeding team made 512 wheat crosses and 236 oat crosses, which is a record number for both crops. They are currently processing seed, analyzing data and preparing for variety releases and fall planting.
“We had 30 inches of rainfall in Baton Rouge between the time the wheat flowered and the time it should’ve been harvested, and that made combine harvesting impossible, so we did a lot of hand harvesting,” Harrison said. “We worked long weekends, working around showers, and we didn’t skip a beat because of COVID, for which I’m proud of my crew. They came in and worked every day, either in the lab or in the field, so the program could keep going at full speed.”
Harrison’s team has released two oat varieties since last year. One of them is going to the TriCal company as a cover crop oat to be planted over a much of the Southwestern and Southeastern United States, and the other is currently being licensed. Both are co-releases with the University of Florida.
The team also expects to release at least one wheat variety this summer. Several advanced breeding lines were increased for release in large breeder seed blocks by the Georgia Seed Development Commission in Plains, Georgia.
“One of them, LA16020LDH-22, is doing extremely well in the regional U.S. Department of Agriculture yield trial across the Southeastern U.S.,” Harrison said. “It’s a doubled haploid, which is expensive technology, and came from a cross made in 2016. This is extremely rapid development of a variety, presuming we release it this summer, which I feel confident about.”
Harrison explained that it will have been released six years after the cross. A normal timeframe is 11 years for double haploids, he said.
Another wheat line is leading the same regional USDA trial across all locations in the South in terms of yield for data that will likely also be released after purification. Harrison said it showed segregation for stripe rust in purification headrows in Winnsboro. There were about 500 headrows growing as a purification block, with around 70% being susceptible to stripe rust. They harvested about 85 completely resistant lines and will use that to make breeder seed to increase the line again next fall, then release it next summer.
Harrison’s team is continuing its critical work on Fusarium head blight, or scab, in wheat, which is by far the No. 1 disease problem that wheat growers face. It is responsible for much of the decrease in acreage Louisiana has seen because it causes yield loss, loss of quality, produces a mycotoxin and it generally makes wheat nonmarketable in bad years. He estimates they’ve spent probably 60% or 70% of their total resources in the last decade in developing Fusarium head blight-resistant wheat and are getting good resistant lines coming out of the breeding program.
“We are processing 1,600 samples of seed that were tested and misted in inoculated nurseries in Winnsboro and Alexandria in collaboration with Boyd Padgett and Trey Price,” he said. “We rate it for field percent scab, then hand-harvest the rows and thresh it in small stationary threshers.”
The process concludes with bringing the seed back to the lab, rating the percent of scabby seed in the lot, grinding it into flour and sending it off to a USDA lab to be analyzed for y-mycotoxin content. The data is included in statewide variety trial publications to aid growers in choosing resistant varieties.
“We publish not only yield and test weight and disease reaction in the field, but all the data from the misted nurseries to give growers an indication of the level of Fusarium resistance and mycotoxin content for all the entries tested in the statewide trials,” Harrison said.
An emphasis is placed on communicating with growers to help them identify high-yielding varieties that will not fall in years when scab is severe. That’s also the major emphasis of the breeding program in lines that Harrison’s team selects and parents that they put into their crossing blocks.
“We put about 40 or 50 parents into our crossing blocks every year, and for every one of those we’ll have molecular marker data that indicates what Fusarium resistance genes are in them,” Harrison said. “We’ll have genomic predictions that tell us what they probably will yield, what disease reaction they’ll have. And we will make all of those 500 crosses knowing what’s in the parent, what we should get out of it, and we always combine lines that have a good level of Fusarium resistance.”
Collaboration is an important part of Harrison’s research. He participates in the national U.S. Wheat and Barley Scab Initiative, a $10 million, 30-state initiative to develop Fusarium resistant varieties, as well as coordinating the SunGrains seven-state collaborative breeding program, which Harrison calls, “a marvel of cooperation.”
“I’ve been here for 38 years now and still enjoy it as much as I did in year two,” Harrison said. “The main difference is that genomic selection was unheard of back then. Now, we have a database that includes thousands of breeding lines tested in the past over dozens of locations and years to get that genomic prediction. This means that farmers are getting access to better varieties that lessen unpredictability.”
About 500 wheat and 250 oat crosses are made in the greenhouse each winter by removing up to 100 anthers with fine forceps to make one of the parents a female, and then pairing it with a male parent chosen to complement the genes in the female and produce a superior progeny. LSU AgCenter photo
SunGrains breeders from Florida, Georgia, South Carolina, North Carolina, Arkansas, Texas and Louisiana get together each summer to review research progress, exchange ideas and make plans for the coming year. This collaboration greatly increases efficiency and effectiveness of the seven breeding programs. LSU AgCenter photo
Wheat breeding lines are evaluated in replicated plots at Baton Rouge, Winnsboro and Alexandria each year. Plots are evaluated by pathologists and the breeding team during the growing season and are harvested with a small plot combine to determine yield, test weight and seed quality. LSU AgCenter photo