b'The University of Arkansas is home to a world-renowned spinach breeding program. Researchers there have worked to develop new varieties for at least 50 years, and they are the only publicly-funded university conducting spinach variety develop-ment. Spinach utilizing University of Arkansas-developed breed-ing lines are incorporated into commercial seed production and found throughout the world. Correll has been working on spinach breeding lines for at least 20 years, and he developed a line of spinach that is resist-ant to white rust. Shi has been working on spinach breeding for at least 10 years and was able to locate genetic markers for disease resistance in the line Correll developed.The molecular breeding technology Shi developed allows him to scan large datasets within spinachs genome to find potential locations that may play a part activating disease resistance. You can compare genomics to a dictionary that is not alpha-betized, says Correll, who is a co-primary investigator on the grant. Shis technology helps us more easily find bookmarks for disease resistance within that unorganized genetic dictionary.In this new grant, Correll and U of A post-doctoral scholar Gehendra Bhattarai will screen 600 unique groups of seeds from four U.S. seed banks, commercial varieties and wild relatives for resistance to each of the five diseases.Since no two diseases are the same, scientists need to better understand how the plants genetic pathways respond to threats from each disease. Identifying these pathways will aid plant breeders in the develop-ment of new varieties.The molecular markers Shi has developed speed up the tra-ditional breeding process and make it much more efficient than traditional breeding techniques, Correll says. A number of his markers are already in use, but this grant will help us add to our toolbox.Once Shi identifies a potential trait or genetic process that triggers disease resistance in spinach, collaborating researchersUniversity of Arkansas researchers Ainong Shi and Jim Correll are will breed cultivars containing that specific trait. Those largerworking to increase disease resistance in spinach using molecular populations will then go into a greenhouse experiment to deter- breeding techniques. mine their merit by observing their environmental and genomic responses to disease pressure. Those that show promise in the greenhouse will go on to field experiments. Those that do wellWe hope the long-term goals of this project include the in field experiments will be made available to plant breeders todevelopment of improved spinach cultivars and breeding lines, develop new breeding lines. improved genetic tools for better breeding methods, and the Shi has already identified several locations on the spinachdevelopment of new spinach varieties that have greater disease genome that may help plants with disease resistance, but moreresistance and are suited to be grown in major U.S. spinach pro-research is needed for scientists to better understand how spin- duction areas, Shi says.ach responds to disease pressure.While the disease markers they find in this study will be spe-Its like trying to develop a dictionary, Correll says. Wecific to the spinach genome, researchers believe Shis molecular know a lot of words, but the dictionary is not completed yet. breeding techniques could be used to find disease resistance The overall goal of the project is to develop spinach cultivarstraits in other vegetables that could be made into new, more that are more resistant to diseases. Researchers will developdisease resistant varieties.molecular tools that they can use to move resistant traitsThe University of Arkansas scientists already have established between plants for new cultivar development. Once disease- relationships with spinach growers and trade associations. They resistance traits are found, seed companies will be able to usewill share their findings from this study during grower meetings.the markers the scientists develop in their breeding programs.Researchers from Texas A&M, USDA- Agricultural Research One of the goals of this project is to reduce growers depend- Station in Salinas, California, Washington State University, ence on pesticides. This is particularly important to organic pro- University of Arizona and University of Massachusetts are also ducers who cannot use conventional fungicides on their crops. contributing to the research project.SW46/ SEEDWORLD.COMFEBRUARY 2024'