PTAB

IPR2013-00023

MonSanto Co v. Pioneer Hi BRed Intl Inc

Log In

1. Case Identification

2. Patent Overview

  • Title: Seed Vigor by Pre-Harvest Defoliation of Maize Plants
  • Brief Description: The ’974 patent relates to methods for enhancing seed vigor in maize plants. The claimed method involves reducing the functional leaf area of maize plants (defoliation) within a specific timeframe after pollination—measured in Growing Degree Days (GDDs)—and subsequently harvesting the seeds.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1, 2, and 8-11 by Hunter

  • Prior Art Relied Upon: Hunter (a June 1989 doctoral dissertation from the University of Kentucky).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Hunter discloses every element of the challenged claims. Hunter describes experiments involving the mechanical defoliation of maize plants to determine the effect on seed vigor. Petitioner’s analysis, based on data in Hunter, calculated that the defoliation occurred at points spanning approximately 515-579 GDDs after pollination. Hunter explicitly teaches that this defoliation treatment can "accelerate seed maturations and the development of maximum seed vigor." The harvested seeds from defoliated plants showed superior cold test emergence compared to undefoliated controls, meeting the "enhanced seed vigor" limitation. Claim 2’s limitation of "mechanical means" is met by Hunter’s disclosure of removing all leaf blades from the plants.
    • Key Aspects: The central argument rests on the assertion that Hunter’s disclosed GDD range of 515-579 anticipates the claimed range of "between about 600 and about 850 GDDs." Petitioner contended that the term "about" and the inherent imprecision of GDD calculations (discussed in Section 4) broaden the claimed range to encompass the values disclosed in Hunter.

Ground 2: Anticipation of Claims 1, 2, and 8-11 by Vasilas

  • Prior Art Relied Upon: Vasilas (a 1986 article in J. Seed Tech.) in view of Vasilas ’85 (a 1985 article in Agronomy J.).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Vasilas describes experiments involving 100% defoliation of maize plants by hand at the "milk (M) stages" of development. While Vasilas does not explicitly state the GDDs, Petitioner used data from Vasilas ’85—which described the same experiments—to calculate that the defoliation occurred at approximately 786 GDDs (using a capped formula) and 860 GDDs (using an uncapped formula). Petitioner argued these values fall within the claimed range of "about 600 and about 850 GDDs." Vasilas reports that cold germination results for the defoliated plants were "higher than [non-defoliated] controls," which Petitioner argued meets the enhanced seed vigor limitation. Defoliation "by hand" satisfies the mechanical means limitation of claim 2.

Ground 7: Obviousness of Claims 1-5 and 8-11 over Hunter in view of Alcantara

  • Prior Art Relied Upon: Hunter (a 1989 doctoral dissertation) and Alcantara (a 1988 article in Weed Tech.).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Hunter teaches enhancing seed vigor through mechanical defoliation at a GDD range close to the claimed range (515-579 GDDs). Alcantara teaches the use of a chemical defoliant (glyphosate, or Roundup®) on maize plants to aid harvesting, with treatments occurring at GDDs calculated to be within the claimed range (e.g., 794-921 GDDs). Although Alcantara’s stated purpose was to enhance kernel dry-down, Petitioner contended the method inherently would have resulted in enhanced seed vigor.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would combine these references to substitute Alcantara’s well-known chemical defoliation method for Hunter’s mechanical defoliation method. Both were predictable and established techniques for reducing the functional leaf area of maize plants to achieve agricultural benefits.
    • Expectation of Success: A POSA would have had a reasonable expectation of success in making this substitution. Since Hunter demonstrated that leaf area reduction at a specific developmental stage enhances seed vigor, and Alcantara provided a known chemical means to achieve that same leaf area reduction at a similar stage, a POSA would expect the chemical method to yield the same vigor-enhancing benefit.

  • Additional Grounds: Petitioner asserted numerous additional anticipation and obviousness challenges based on combinations of Hunter, Vasilas, Alcantara, and Major (a 1980 journal article). Further obviousness grounds incorporated Albrecht (Patent 5,491,125) for its teachings on specific herbicides and surfactants.

4. Key Claim Construction Positions

  • Petitioner argued for a broad interpretation of the claim phrase "between about 600 and about 850 GDDs after pollination." This interpretation is allegedly necessary for several reasons:
    • The use of the imprecise qualifier "about" applies to both endpoints of the range.
    • A POSA would have understood that determining the precise start point of GDD counting (i.e., the moment of pollination across an entire stand of maize) is inherently imprecise.
    • The process of defoliation itself can take several days, during which significant GDDs can accumulate, creating further imprecision in the endpoint.
    • The art recognized at least two different methods for calculating GDDs ("capped" and "uncapped" formulas), which yield different results from the same temperature data. The patent’s specification references both methods.
  • Based on these factors, Petitioner contended that the claimed range is broad enough to encompass GDD values disclosed in the prior art that are numerically outside 600-850, such as Hunter’s ~515 GDD and Alcantara’s ~921 GDD.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-11 of Patent 6,162,974 as unpatentable.