ALEXANDRIA, Va.  -- Recently published American Seed Trade Association research helps provide the corn breeding community with practical guidelines to help determine if a variety is essentially derived and aids in resolving concerns relating to this issue.

The concept of an essentially derived variety (EDV) was introduced by the International Union for the Protection of New Varieties of Plants in their 1991 revisions, but didn't include definitive parameters; thus these revisions have been subject to interpretation.

An EDV is a variety that retains the essential characteristics of and is predominantly derived from an existing parental variety which has a Plant Variety Protection Act certificate. In simple terms, an EDV is a variety that is deemed to be genetically very close to an existing parental variety which is protected.

It is a violation of plant variety protection laws to copy or plagiarize protected varieties, but the laws do not prevent others from breeding with those varieties.

ASTA has taken a proactive approach to provide a practical understanding and bring clarity to what might qualify as an EDV in corn, said Stephen Smith, a co-author of the study and research fellow at Pioneer Hi-Bred, a DuPont business. The published information provides a genetically based measurement tool to help make that determination.

ASTA's proactive research resulted in the identification of 285 publicly available simple sequence repeat (SSR) markers which can be used for variety identification and to help determine whether a corn variety may be an essential derivation.

"The markers act like a genetic fingerprint," said Ron Ferriss, a co-author of the study who heads product clearance and license compliance at Syngenta Seeds. "To use this tool, one would essentially fingerprint the two inbred lines with this marker set and then compare fingerprints to measure the similarity of the two varieties."

The research, "North American Study on Essential Derivation in Maize: II. Selection and Evaluation of a Panel of Simple Sequence Repeat Loci," is published in the March-April 2010 edition of Crop Science and is available online. The table of markers with isozyme and SSR profiles of the publicly available inbreds that were used in the study are available on ASTA's Web site at

"This research is important because it reinforces the understanding that plant breeders can protect the products in which they have invested their time, resources and research efforts," said Bernice Slutsky, ASTA vice president of international programs. "Guidelines for helping determine what constitutes an EDV create an awareness of plant variety protection laws and improve the research environment. This improved environment encourages breeders to generate new, more productive varieties, while contributing to improved stewardship of the corn genetic resource base."

Few would be willing to invest in breeding efforts if ownership of a variety could be lost to others who made only small cosmetic changes to the initial parental variety and then marketed the product as theirs. The introduction of the EDV concept into Plant Variety Protection laws is designed to prevent such occurrences.

It is not often that disputes occur, but when they do these tools should enable parties to more easily determine what constitutes an EDV in corn and help resolve the issue in a timely manner.

The eight-member team of researchers who worked on this project are members of the Corn Variety Identification Subcommittee within ASTA.