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What Can USDA-ARS Do to Aid the Sunflower Industry?
Wednesday, August 31, 2022
filed under: Research and Development
Left to Right: Brent Hulke, USDA-ARS sunflower research geneticist and acting
unit research leader; Bill Underwood, research plant pathologist, and Jarrad Prasifka,
research entomologist. The trio addressed the 2022 NSA Summer Seminar
audience, outlining the unit’s work and inviting input on future ARS priorities.
Scientists with the USDA Agricultural Research Service (ARS) have generated extremely valuable sunflower research on several fronts across the past five decades: breeding, wild relatives collection/distribution, plant pathology, insect biology/management, and sunflower oil quality being among the primary disciplines. The agency’s sunflower research effort continues to move forward as of 2022, advancing the knowledge of, and uses for, this incredible plant and its numerous species.
Brent Hulke is sunflower research geneticist and current acting research leader for the ARS Sunflower and Plant Biology Research Unit at Fargo, N.D. He and two fellow Fargo unit scientists, plant pathologist Bill Underwood and entomologist Jarrad Prasifka, came to the 2022 NSA Summer Seminar to outline their current work — and to invite input from those in attendance regarding the future direction of ARS sunflower research.
“USDA really is here to help all of agriculture and food consumers with the best available science,” Hulke stated in his opening remarks. One of the primary components in the mission statement of the ARS Edward T. Schafer Agricultural Research Center in Fargo, he noted, is to “develop knowledge and technology to benefit the sunflower industry.” That objective takes on a particular urgency in current times, he added, since “we expect major changes in scientist and support staffing in the next few years [due to retirements and other departures], providing opportunities to refocus that only come around every 15 to 30 years.”
Hulke then introduced the current group of sunflower scientists at the Fargo ARS unit and highlighted some of their key products and services in recent years:
• Insects / Jarrad Prasifka, Research Entomologist — Bee research has identified the most important traits that determine bee preference for sunflower lines. The Fargo team also has found markers for genes that govern both bee preference and seed size/shape. Research on sunflower seed weevil has resulted in the release of germplasm that reduces damage to inbreds by up to 75% — and, damage to hybrids by up to 50%. Also, a degree-day model has been developed for adult seed weevil emergence to aid with planting time planning.
• Plant Pathology / Bill Underwood, Research Plant Pathologist — Underwood and his predecessor, Tom Gulya, have contributed extensively to the development and release of new sunflower germplasm for resistance to downy mildew, rust and Verticillium wilt, among other diseases. The ARS plant pathology effort also includes collaborative research to map genetic loci for Sclerotinia, Phomopsis and downy mildew resistance. Underwood likewise has focused on the development of an improved method for evaluating resistance to Sclerotinia basal stalk rot. A current “work in progress” is the characterization of physiological mechanisms contributing to Phomopsis resistance and identification of germplasm resources with distinct forms of resistance.
• Botany / Gerald Seiler, Research Botanist — Across the past four-plus decades, Seiler, by far the longest-serving scientist on the Fargo ARS team, has assembled the largest global collection of sunflower crop wild relatives (CWR), ensuring potential genetic diversity for sunflower improvement for future generations. Out of that collection have come 37 downy mildew resistance genes, 17 rust resistance genes, and genes providing resistance for Sclerotinia basal stalk rot and head rot. The sunflower CWR also have provided genes for Phomopsis resistance — and, as well, the genes utilized for IMI and SU herbicide resistance. More than 60 interspecific pre-breeding germplasms have been developed and released from annual and perennial crop wild relatives for deployment into cultivated germplasms.
• Molecular Genetics / Lili Qi, Research Molecular Geneticist — “Our molecular geneticist group has done a lot of work in fine mapping and cloning these genes so that we have good genetic markers to follow while we’re doing breeding — not just for our [ARS] work, but for industry,” Hulke stated. Among Qi’s accomplishments have been the release of confection sunflower lines with downy and rust resistance “gene stacks” and the development of interspecies genetic stocks for the mining of disease resistance genes — “a really difficult thing to do,” Hulke underscored.
• Breeding Program / Brent Hulke, Sunflower Research Geneticist — “We’ve released a lot of new genetics and continue to do so year after year,” Hulke noted. He estimates that more than 300 inbred lines and genetic stocks have been made accessible to commercial breeders across the span of the past 45-50 years. Those releases have carried such traits as Express® and Clearfield® tolerance, high-oleic acid, numerous disease resistances, the first pest-insect resistance traits — and, in recent years, increased adaptation e.g., days-to-maturity range and fitness for specific locations (“niche” germplasm diversity). The ARS sunflower breeding program also has concentrated on detailed mapping of disease and pest/beneficial insect interaction genes on the sunflower genome, Hulke reported, “in order to more efficiently deploy breeding research in the future.”
Following his outline of ARS sunflower research highlights, with additional input from Prasifka and Underwood, Hulke invited the NSA Summer Seminar audience to ask questions and provide suggestions regarding the ARS group’s future research priorities. “What types of research should we do in the future?” he queried. “What types of products and services do you want to see delivered to the industry going forward?”
Audience members responded with several questions, including the following (with Hulke’s response summarized after each question).
• How old, or new, is the germplasm you are using? It’s ever evolving.
• Can we get oil content higher than around 50%? It seems like right around 52-53% would be the highest; but seed yield is also likely to go higher, so the overall pounds of oil per acre would correspondingly increase.
• Will more-diversified hybrids be developed, e.g., more geographic diversity? Yes, but a big factor is the expense of diversification for seed companies, given sunflower’s relatively small acreage compared to crops like corn or soybeans. Progress with earlier-maturing varieties for use in double-crop situations is certainly viable and is likewise being actively researched.
• Since levels of host plant resistance to the seed weevil have been discovered and are being further developed, could similar resistance to sunflower moth and/or banded moth be found and developed? Yes, but progress there is not nearly as far along as with the seed weevil.
Hulke, Underwood and Prasifka all emphasized their desire for feedback from sunflower growers and industry as to future needs and opportunities. They also plan to come together over the next several months with the NSA Board of Directors to review such input and to strategize about the long-term goals and priorities of the ARS unit. — Don Lilleboe