The leading cases concerning the interpretation of the exclusion from patentability of essentially biological processes for the production of plants are the consolidated cases G 2/07 (OJ 2012, 130) and G 1/08 (OJ 2012, 206) ruling on the referral in T 83/05 of 22 May 2007 date: 2007-05-22 (OJ 2007, 644) relating to a method of obtaining particular broccoli lines and on that in T 1242/06 of 4 April 2008 date: 2008-04-04 (OJ 2008, 523) relating to a method of breeding tomato plants which produce tomatoes with reduced fruit water content.

The Enlarged Board of Appeal found, first of all, that the exception applying to "essentially biological processes for the production of plants" could not be read as limited to processes for the production of plant varieties, because such an interpretation would be contrary to the wording.

After rejecting a series of possible approaches to the interpretation of the exclusion, the Enlarged Board concluded that a non‑microbiological process for the production of plants which contains or consists of the steps of sexually crossing the whole genomes and of subsequently selecting plants is "essentially biological" within the meaning of Art. 53(b) EPC. Such a process does not escape the exception to patentability merely because it contains, as a further step or as part of any of the steps of crossing and selection, a step of a technical nature which serves to enable or assist performance of the steps of sexually crossing the whole genomes of plants or of subsequently selecting plants.

This outcome was largely based on the Enlarged Board's findings with regard to the legislative history of the Strasbourg Patent Convention and the EPC 1973. The legislator's intention, it found, had been to exclude from patentability those plant breeding processes which were the conventional methods of plant-variety breeding at the time. These conventional methods included, in particular, those based on the sexual crossing of plants (i.e. of their whole genomes) deemed suitable for the purpose pursued and on the subsequent selection of the plants having the desired trait(s). It could also be gathered from the legislative history that the mere use of a technical device in a breeding process was not to be considered sufficient to lend the process itself a technical character.

The Enlarged Board distinguished such processes from those which left the realm of plant breeding. It cited R. 27(c) EPC, which expressly provides that biotechnological inventions are also patentable if they concern a microbiological or other technical process, so that the excluded essentially biological processes are juxtaposed with the patentable technical processes. The exception to patentability under Art. 53(b) EPC does not exclude a process of sexual crossing and selection which includes within it an additional step of a technical nature, which step by itself introduces a trait into the genome or modifies a trait in the genome of the plant produced, so that the introduction or modification of that trait is not the result of the mixing of the genes of the plants chosen for sexual crossing. In the context of examining whether such a process is excluded from patentability as being "essentially biological" within the meaning of Art. 53(b) EPC, it is not relevant whether a step of a technical nature is a new or known measure, whether it is trivial or a fundamental alteration of a known process, whether it does or could occur in nature or whether the essence of the invention lies in it.

Ultimately, this means that, while the presence in a claim of one feature which could be characterised as biological does not necessarily result in exclusion of the claimed process as a whole under Art. 53(b) EPC, the same does not apply where the process includes sexual crossing and selection.

In T 2323/11 the invention concerned the removal of unwanted sequences from the genome of transgenic plants which comprise an introduced gene for an agronomically valuable trait. In G 2/07 and G 1/08 the Enlarged Board considered that, under Art. 53(b) EPC, excluded processes were characterised by the fact that the traits of the plants resulting from the crossing were determined by the underlying natural phenomenon of meiosis. The board held – contrary to the appellant’s argument – that the trait of the excision of the target gene is the result of the crossing of the parent plants and is determined by the underlying natural phenomenon of meiosis, as the latter determines the genetic make-up of the plants produced. The claimed method therefore did not fall under the exception made in G 2/07 and G 1/08 for those processes which contain an additional step of technical nature.

In T 915/10 the invention concerned soybean plants which had been genetically modified. The claimed method was defined solely by the technical process step of introducing a gene sequence into the genome of the plant by a genetic engineering step introducing heterologous DNA in plant cells. The board noted that the introduced trait was due directly to the expression of the inserted DNA and was not the result of a plant breeding method characterised by crossing and selection. Indeed, the method as claimed did not require nor define steps of mixing genes of plants by sexual crossing and subsequent selection of plants, either explicitly or implicitly. The board was thus satisfied that the claimed method did not fall under the exclusion of "essentially biological processes for the production of plants" pursuant to Art. 53(b) EPC. The board considered that the claimed subject-matter was a method for the production of plants by means of genetic-engineering techniques, which involves laboratory techniques essentially different from breeding methods and which as such have been accepted in the case law to be patentable. The board noted that there was nothing in decisions G 2/07 and G 1/08 which would indicate that the Enlarged Board of Appeal was of the opinion that this practice ought to be reconsidered as a result of its analysis of the process exclusion in Art. 53(b) EPC.