U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home News & Events News Articles Research News 2022





- ARS@Work
- Blog
- Down on the Farm
- Image Gallery
- News Archive
- Podcasts
- Press Room
- Science in Your Shopping Cart
- Scientific Discoveries
- Tellus
- Under the Microscope
- YouTube Channel

**Viral Tag Team Stymied by New Corn Germplasm** Contact: Jan Suszkiw Email: Jan.Suszkiw@usda.gov June 14, 2022 A new corn germplasm resource developed by Agricultural Research Service (ARS) scientists in Wooster, Ohio, is now available to use for breeding commercially grown varieties that can withstand the synergistic viral disease, maize lethal necrosis (MLN). First reported in the late 1970s in Kansas and Nebraska, MLN today has become a global threat to corn (maize) production worldwide, particularly in East Africa, where initial outbreaks in Kenya inflicted yield losses of up to 90 percent. Maize lethal necrosis also is problematic in South America and Asia. The disease strikes when corn plants are co-infected by the maize chlorotic mottle virus, which was first detected in Peru, and by maize-infecting potyviruses, which occur globally. Foliar symptoms progress from minor yellow mottling and mosaic-like symptoms to severe necrosis throughout the leaf. Other symptoms include stunted growth, premature aging, poor grain-fill of ears and drying of the entire plant followed by death. Growers use a combination of methods to prevent or minimize MLN. These include controlling weeds like johnsongrass that can serve as reservoirs of the viruses as well as the insects that transmit them while feeding. Another tactic is rotating corn with non-host crops on which the culprit viruses cannot survive. However, planting disease-resistant varieties is the cornerstone defense, noted Erik Ohlson and Mark Jones, both with the ARS's Corn, Soybean and Wheat Quality Research Unit in Wooster. Toward that end, the two ARS researchers developed the "synthetic" corn population OhMCMV-1 as a germplasm resource. Resistance to maize chlorotic mottle virus is rare and OhMCMV-1 offers breeders a new breeding resource with novel combinations of resistance genes that can be used. Scientists are working to shore up the defenses of corn against maize lethal necrosis, a global threat of the crop. (Photo by Preston Keres, USDA) "A synthetic population is a term used to describe a breeding population that was developed from several parental lines with a specific trait or breeding goal," Ohlson, a plant geneticist, explained. "In this case, five MLN-tolerant corn lines were cross-pollinated with each other in all combinations over multiple generations to recombine the genetic backgrounds from these five parents." The researchers selected the most maize chlorotic mottle-tolerant plants to recombine and advance to the next generation, a breeding strategy called recurrent selection. Growth chamber tests show that OhMCMV-1 plants can withstand the viruses that cause MLN as well as or better than its five parental lines. Credit for that goes to new combinations of multiple unique resistance genes from the five parental corn lines used for population development. OhMCMV-1 is not intended for commercial production directly, but rather as breeding material from which elite commercial varieties or hybrids can be developed, according to the researchers, who published the results of their evaluations of OhMCMV-1 in the *Journal of Plant Registrations.* The population is being released after one cycle of selection for tolerance to maize chlorotic mottle virus and a second cycle of selection is in progress, added Jones, an agronomist. "The maize lethal necrosis epidemic in East Africa was a major consideration when this project was undertaken, but OhMCMV-1 has value for anywhere the maize chlorotic mottle virus occurs or maize lethal necrosis is or may become problematic," Ohlson said. Current practices used by U.S. corn growers have kept the disease in check, coupled with the limited occurrence of maize chlorotic mottle virus. However, OhMCMV-1 can nonetheless be adapted to conditions in the U.S. Corn Belt, if necessary—thanks to a temperate-adapted parent among the five that were used. Small quantities are available to qualified professional plant breeders and other research scientists upon request. *The Agricultural Research Service is the U.S. Department of Agriculture's chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $17 of economic impact.*


Return to top


Research
                            Media
                            About ARS
                            Work With Us


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov