Gene Flow in Alfalfa: Biology, Mitigation, and Potential Impact on Production

CAST papers are the foundation of CAST’s science communication work. Developed by expert-led task forces, these peer-reviewed publications translate agricultural science into trusted insights that inform policy, guide public understanding, and fuel CAST programs, dialogues, and educational initiatives.

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October 16, 2008
Special Publication

DOI: https://doi.org/10.62300/rnbr0547

Task Force Chairs

Allen E. Van Deynze

University of California–Davis

Authors

Sharie Fitzpatrick

Forage Genetics International, West Salem, Wisconsin

Bob Hammon

Tri River Area Extension, Grand Junction, Colorado

Mark H. McCaslin

Forage Genetics International, Prior Lake, Minnesota

Daniel H. Putnam

University of California–Davis

Larry R. Teuber

Foundation Seed Program, University of California–Davis

Daniel J. Undersander

University of Wisconsin–Madison

Abstract

This publication addresses gene flow in alfalfa (Medicago sativa L.) and its implications for coexistence among genetically engineered (GE), conventional, and organic production systems. It explains biological and agronomic factors influencing gene movement via pollen and seed, and outlines mitigation strategies to minimize adventitious presence (AP) of GE traits in sensitive markets. Key findings indicate that gene flow in hay production is extremely low due to frequent harvests before seed set, while seed production poses higher potential risk but can be effectively managed through isolation distances, pollinator control, and best management practices. The report emphasizes science-based coexistence strategies, including certified seed use, crop rotation, and removal of feral plants, to maintain genetic purity and market access.