Robert Dale Riggs, PhD

Riggs, Robert 4170622_4267589 TP

Title: Plant Pathology and Nematology Educator, Researcher
Location:  Fayetteville, Arkansas, United States

Robert Dale Riggs, PhD, plant pathology and nematology educator and researcher, has been recognized by Marquis Who’s Who Top Scientists for dedication, achievements, and leadership in research.

With expertise in plant pathology that includes economical and environmentally safe methods to control soybean cyst nematode (SCN), one of the most serious pests of soybeans in the United States, Dr. Riggs has played an important role in his industry for the last six decades. He was inspired to enter this field because of his upbringing, which included living and working on a farm. From a young age, he recognized the need for solutions to plant diseases that often grew on crops. Upon graduating high school, Dr. Riggs received a $200 grant, which he utilized to pursue his higher education – a feat that he hadn’t expected to become a reality for him. He attended the University of Arkansas, where he earned a Bachelor of Science in agriculture in 1954 and a Master of Science in plant pathology in 1956. From there, he received scholarships and grants to continue his education. In 1958, Dr. Riggs earned a PhD in plant pathology from North Carolina State University. His first role in the field was work as an assistant professor for the University of Arkansas, which he excelled in for four years before moving up to the associate professor level. By 1967, Dr. Riggs was a full-time professor with the university. He continues to share his expertise in this role today.

Notably in his career, Dr. Riggs has provided leadership in the testing of soybean cultivars for resistance to SCN that led to the development of resistant cultivars and better variety selection for growers. In order to develop control measures for SCN, Dr. Riggs extensively studied the genetic variability of both the nematode and the soybean. With D. Schmitt, he defined 16 possible races of SCN using differential soybean varieties and encouraged the development of standardized methods to determine races. With his students, Dr. Riggs further defined races using serology as well as isozyme and DNA analyses. Collaborative work with C. E. Caviness worked to determine the genetics of resistance to SCN and has resulted in the release of six disease resistant cultivars. Further studies have identified specific ultrastructural differences in the response of susceptible and resistant soybeans. Because of this impactful work, Dr. Riggs has been afforded several opportunities in his tenure to impact his industry on a wide scale. He has served as the president and vice president for the Society of Nematologists, editor-in-chief of the Journal of Nematology, editor of Nematology in the Southern United States, and co-editor of “Biology and Management of the Soybean Cyst Nematode.” Dr. Riggs is also a member of the American Phytopathological Society, the Southern Soybean Disease Workers, the University of Arkansas Alumni Association, the Organization of Nematologists of Tropical America, Sigma Xi, and Gamma Sigma Delta.

In recognition of the professional excellence he has demonstrated in his career, Dr. Riggs has been the recipient of several awards. He achieved a Meritorious Service Award from the United Soybean Board, an Outstanding Researcher Award from the Arkansas Association of Cooperative Extension Specialists, an  Honorable Award for Research in Environmental Protection from the U.S. Department of Agriculture, a district faculty achievement award from the University of Arkansas Alumni Association, a distinguished service award from the Southern Soybean Disease Workers, and an Outstanding Plant Pathologist Award from the Southern Division of the American Phytopathological Society. Additionally, Dr. Riggs is regarded highly by his peers for his research on the combined use of crop rotation and resistant soybean cultivars for the control of SCN. From studies of host range, genetic variability of the nematode, and race shifts in SCN resulting from prolonged use of resistance genes, Dr. Riggs developed a 3-year-rotation schedule that consists of a susceptible soybean cultivar, a resistant soybean cultivar, and a nonhost such as grain sorghum. The rotation schedule, which reduces SCN population levels and slows race shifts, is designed to enhance the durability of resistant cultivars. It is the current SCN control strategy recommended by the Arkansas Cooperative Extension Service and is used by growers throughout the South. As he looks ahead to the future, Dr. Riggs intends to continue in his work as a researcher, which currently includes exploring the effectiveness of a fungus for the biological control of SCN.

For more information, please visit:

Lifetime Achievement

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