Corn Patent Information System
Searchable Maize and Corn Patent Data

Definitions and Explanations

715c15cc-fbd1-4355-ae64-f243b6ade2f5Background
This database contains field corn germplasm only.  It does not include patented nor PVP-protected sweet corn or popcorn germplasm.

For purposes of this database, heterotic groups have been classified into 5 categories:

  1. BSSS – Stiff Stalk and stiff stalk related germplasm or germplasm that acts similar to BSSS
  2. Lancaster – Wide range of germplasm including C103, C123, Mo17, Oh43, Oh07, and more.
  3. Iodent
  4. W153R – Primarily LH82-derived and similar types of germplasm.
  5. Unrelated – Including germplasm that is largely unrelated to or heterotically responsive in patterns unlike the four categories listed above.

Heterotic groups are often somewhat subjective and prone to exceptions, not unlike higher order botanical species classifications.  For this reason, more extensive and detailed classification of families and/or sub-families has not been provided in this database.  The classification listed for individual maize inbreds is based upon analysis and interpretation of data obtained from published patent and PVP documents.  Analysis and interpretation of published data were performed solely by the authors of this database, and to the best of their abilities.  No warranty or guarantee of the absolute accuracy of these interpretations is provided or implied.

Some corn inbreds may have multiple classifications listed for heterotic background, eg. – Iodent-Lancaster, or Lancaster-Iodent.  In these cases, the genetic background of the inbred is more like the first-listed heterotic group than the second-listed heterotic group.  Again, this is subject to the limitations and interpretation of available data.

Patent expiration dates
US patent expiration dates have been determined based upon laws and protocols prevalent at the time of each patent issue.  The current rules determining expiration date are rather long and complicated.

In general, since June 8, 1995, US patent protection has been in force for 20 years following the FILING DATE (Application Date) of the patent in most cases.  Prior to May 28, 2000, if the time transpired between the patent filing date and the patent issue date was longer than three years (1096 days), the duration of US patent protection was usually extended.  In such cases, the US patent expiration date was determined to be 17 years following the ISSUE date of the patent.

Since May 28, 2000, (generally for expiration dates after May 28, 2020) patent protection usually lasts for 20 years from the filing date PLUS an extension of “x number of days” following 20 years after the filing date.  This extension is determined by a large number of factors, and is calculated by the US Patent and Trademark Office on a case-by-case basis.  Hence, patent protection lasts for 20 years plus the number of extension days.  Extension days can range from 0 to several hundred days.

Prior to June 8, 1995, US patent protection was in force for 17 years following the application date of the patent, or 14 years following the approval date of the patent, whichever is later.

The database reflects these changes in patent law, and the time periods for which they apply.

Patent maintenance fee neglect
The US patent office requires a maintenance fee to be paid by 4 years, 8 years, and 12 years (including 6-month grace periods) following the issue date of each patent.  If these fees are not paid by the end of any grace period, the patent is deemed expired.  The CPIS database reflects all patent expirations occurring as a result of neglected maintenance fee payments by the patent holder as they occur.

Plant variety protection (PVP) expiration dates
PVP certification is currently in force for 20 years from the date of issuance of the PVP certificate.  Prior to 1980 PVP certification was in force for 17 years from the date of PVP certificate issuance.  From 1980 to 31 March 1995 PVP certification was in force for 18 years from the date of PVP certificate issuance.

Variety names
Occasionally, the same corn inbred variety has been assigned different names by the inventor/developer for PVP certification vs. patent protection.  Where identifiable, these variety names have been consolidated as one variety entry in the database.  In other cases, the same inbred may have been patented using one name and PVP-certified using another name.  Where possible, these names are both entered in the database.  In such cases, the inbred will be entered twice in the database, once with the patented inbred name entered as the “Variety Name” and the PVP inbred name as the “Other Name”, and then again with the PVP name as the “variety Name” and the patented inbred name as the “Other Name”.

Some inbred varieties have been patented two or sometimes three times by the patent owner.  Such inbred varieties are identified by an (xofn) suffix immediately following the name of the variety.  A (1of2) designates the first patent; a (2of2) designates a second patent; a (1of3), (2of3), and (3of3) designate the 1st, 2nd, or 3rd patents of a single inbred.  If the patent of an inbred variety possessing a (1of2) suffix has expired, the inbred may still be under protection via a second or third patent.  If no (n) suffix is present, the inbred variety has been patented only once, though it may still be under protection of a PVP certification.

Parental pedigree nomenclature
Parental pedigrees of corn inbreds are listed (whenever known) with the female parent listed first followed by the male parent listed last.  Where more than two parents are identified in the development of the maize inbred, parenthesis () are used to enclose the varieties used as one parent of the final cross.  For example, in the development of inbred X, the parental pedigree A / (B / C) indicates that the progeny of the cross B / C was used as the pollinator (male parent) to pollinate A (female parent) in the development of the population from which X was developed.  In this theoretical example, X is expected to possess a nuclear genetic background consisting ½ A, ¼ B, and ¼ C, and a cytoplasmic background of A.

Where backcrossing was identified in the development of the corn inbred, > or < are used to identify which parent was used multiple times (recurrent parent) in the crossing scheme.  Again, the female parent (of the final backcross) is listed first.  The male parent (of the final backcross) is listed last.  The symbols >n> or <n< are used to indicate the direction and recurrence of one parent in the backcross scheme.  For example, in the development of inbred Y, D<3<E indicates that E is the recurrent parent used a total of three times (including the original cross) to develop the backcross population from which Y was developed, and D was the female of the final backcross.  In this theoretical example, Y is expected to possess a nuclear genetic background consisting 7/8 E and 1/8 D, and a cytoplasmic background of D.

Publication inclusion

Please note that patent and PVP information is available only for germplasm for which patents or PVP certificates have been issued.  If a variety patent application was submitted but is still pending, or was later withdrawn or abandoned before the patent was approved and published, the variety is not included as an entry in the database.  If PVP applications are still pending, they also do not contribute to this database.  Also, note that some information for some varieties was not possible to derive from the published literature, nor from subsequent data analysis.

For more comprehensive tracking of genetic ancestry, a number of older, publicly-developed “founder” inbred lines, e.g. – A632, B73, B14, C103, MO17, etc., have been incorporated into the database, even though these founder inbred lines were not patented nor PVP-protected.  Pedigrees of these founder inbred lines were provided with permission from and courtesy of MBS Genetics, LLC.