Japan StrengtheJapan Strengthens Plant Variety Protection: The 2026 Amendment to the Seed and Seedling Act – Extending breeders’ rights and closing the pre-registration leakage gap

Japan has long been a source of premium, painstakingly bred agricultural varieties — from the ruby-red strawberry cultivar Beni-hoppe to the seedless grape Shine Muscat, whose export value has been eroded for years by “unauthorized” cultivation abroad after cuttings or seedlings left the country before, or shortly after, variety registration. On 17 July 2026, the Diet passed a comprehensive amendment to Japan’s Seed and Seedling Act (Shubyo-ho), the domestic statute implementing UPOV 1991, aimed squarely at this leakage problem and at modernising enforcement of breeders’ rights more generally. Most provisions enter into force on 1 December 2026.

Recap: Japan’s “double protection” of plant varieties under patent law and the Seed and Seedling Act

Before turning to the amendment’s specifics, it is worth recalling a structural feature of Japanese law that is not obvious to practitioners from UPOV jurisdictions that prohibit dual protection: in Japan, the same plant material can be protected simultaneously under two independent regimes. Japan’s Patent Act (Tokkyo-ho) contains no equivalent of Article 53(b) EPC excluding “plant varieties” or “essentially biological processes” from patentability, so a gene-edited trait, transformation method, or specific genetic construct can be patented in its own right. Separately, a specific commercial variety embodying that trait can be registered as a breeder’s right (Ikuseisha-ken) under the Seed and Seedling Act. The two statutes are drafted to interlock rather than collide: Article 21, paragraph 2 of the Seed and Seedling Act carves out, from the scope of a breeder’s right, acts performed by a patentee or licensee practising a patented method to produce seeds or seedlings of the registered variety — including continued practice after the patent expires. This dual-track structure is increasingly relevant in practice — for example, for gene-edited crops such as the high-GABA tomato commercialised by Sanatech Seed, where the trait itself is patent-protected while the specific cultivar is separately variety-registered. The 2026 amendment strengthens only the breeder’s-right side of this pairing; right holders active in plant biotechnology should review both tracks together in its light.

1. A significant extension of the term of protection

The headline change is a ten-year extension of the statutory term of breeders’ rights:

• Ordinary (herbaceous) varieties: 25 years → 35 years from the date of variety registration.
• Perennial and woody varieties (fruit trees, forest trees, etc.): 30 years → 40 years from registration.

Notably, the extension applies retroactively to rights already subsisting at the effective date, giving existing right holders an immediate and substantial windfall in remaining protection. The stated rationale is that the long lead time needed to breed a new variety and establish it commercially — often a decade or more — was not adequately reflected in the previous term.

2. Closing the pre-registration “window of exposure”

Variety registration in Japan typically takes three to six years from filing, and until now an applicant had no enforceable right during that period — a gap that has repeatedly been exploited to move planting material out of the country before protection attached. The amendment introduces two new tools targeted at this gap:

• Right to seek an injunction against unauthorised export of the seeds, seedlings, or (for purposes other than final consumption) harvested material of an applied-for variety, once the application has been published and a written warning has been given to the infringer.
• Extension of the right holder’s control to storage for export purposes: where a right holder has designated permitted export destinations, storing propagating or harvested material for export to a non-designated country is brought within the scope of the right — in effect, a statutory exception to exhaustion aimed at warehouses and logistics hubs near ports.

3. Easing the burden of enforcement

Several amendments respond directly to the practical difficulties breeders have faced in litigation:

• New Article 35-3 creates a presumption that seeds or seedlings offered or transferred under the name of a registered variety are, in fact, that registered variety — shifting the practical burden of disproving identity onto the alleged infringer.
• Damages calculation is rationalised: a right holder may claim a reasonable royalty even for quantities exceeding its own production or licensing capacity, and courts may take into account an “infringement premium” — i.e., that a hypothetical negotiated licence agreed against the backdrop of known infringement would command a higher rate than an arm’s-length licence.
• A third-party (amicus) opinion mechanism is introduced, modelled on the system already used in patent invalidation and infringement litigation, allowing courts to solicit expert or industry views in variety-right disputes of general importance.

4. “Lease” formally added as a regulated act of exploitation

The Act’s definition of “exploitation” is amended to expressly include leasing of propagating material, together with associated offering, display, and advertising for lease. Lessors will also be subject to variety-registration labelling and name-use obligations, breach of which is now punishable by an administrative fine of up to ¥200,000, doubled from the previous ¥100,000 cap.

5. Practical implications

For breeders and licensees, the extended term materially increases the value of an existing or pending Japanese variety portfolio and warrants a fresh look at licensing terms drafted around the old expiry dates. For traders, nurseries, and logistics operators handling Japanese-origin planting material for export, the new pre-registration injunction and storage-for-export provisions mean that compliance diligence can no longer wait until a variety is formally registered — published applications now carry real enforcement risk. For litigators, the new presumption of identity and the amicus mechanism are likely, over time, to bring variety-right litigation practice closer to the more developed evidentiary and procedural framework long familiar from Japanese patent litigation — a convergence international practitioners accustomed to Japan’s patent system may find easier to navigate than the variety-right regime has traditionally been.

More broadly, the amendment is a further, concrete illustration of a trend AIPPI members will recognise from several UPOV 1991 jurisdictions: as premium agricultural genetics become a more visible target of unauthorised cross-border propagation, breeders’ rights regimes are being re-tooled with enforcement mechanisms — provisional protection, presumptions, and amicus procedures — that were previously the preserve of patent law. Japan’s 2026 amendment is a notable, and comparatively ambitious, example of that convergence.

6. Concluding Remarks

Beyond the specific mechanics described above, the 2026 amendment may be read as evidence of a broader shift under way in Japan’s approach to plant innovation policy. For much of the post-war period, agricultural variety protection operated as a comparatively quiet, domestically oriented regime running parallel to, but rarely intersecting with, Japan’s far more assertive patent strategy in pharmaceuticals, electronics, and — more recently — gene-editing technology. The 2026 amendment narrows that gap: by importing patent-style tools — provisional pre-registration protection, evidentiary presumptions, an amicus procedure, and enhanced damages — directly into the Seed and Seedling Act, the legislature appears to treat premium plant genetics as a strategic export asset warranting the same enforcement sophistication historically reserved for technology and pharmaceutical patents. Combined with the commercial emergence of gene-edited crops that straddle both protection regimes (see Section 0 above) and with the government’s broader push to curb the outflow of Japanese agricultural germplasm, this amendment may prove to be less an isolated fix to the “Shine Muscat problem” than an early move in a more coordinated, IP-centred national strategy for plant innovation. Whether that ambition survives the practical difficulties of cross-border enforcement remains to be seen, but for AIPPI members advising breeders, seed companies, or agri-biotech investors with interests in Japan, this is a space worth watching closely over the next few years.