Trade-related Aspects of Intellectual Property Agreement (TRIPS)

What is the TRIPS Agreement?

The Trade-related Aspects of Intellectual Property Agreement is one of the agreements of the of the World Trade Organisation (WTO) adopted in 1994 at the close of the Uruguay Round of negotiations under the General Agreement on Tariffs and Trade (GATT).

It entered into force in 1995, simultaneous with the inauguration of the WTO, the creation of which was also an outcome of the Uruguay Round. The rules of the TRIPS Agreement state how copyrights, patents, trademarks, geographical names used to identify products, industrial designs, integrated circuit layout-designs and undisclosed information such as trade secrets — “intellectual property” — should be protected when trade is involved. The TRIPS and other WTO agreements are binding upon the 157 countries that are members of the WTO.
Further reading: WTO TRIPS website.

It is important to keep in mind that least developed countries do not have to implement the TRIPS requirements for the time being.

TRIPS does  not  prescribe UPOV to WTO member states

Article 27.3(b) of TRIPS provides that WTO "Members shall provide for the protection of plant varieties either by patents or by an effective sui generis system or by any combination thereof.”

"Sui generis" is a latin term used in legal texts, meaning "of its own kind". TRIPS does not even mention UPOV. It has become common to call non-UPOV systems sui generis systems. This is confusing, but important is: WTO member countries can provide any kind of plant variety protection, either by patents, or by a sui generis system (UPOV or non-UPOV). Combinations are also possible.

What would constitute an effective sui generis system has not been defined in the TRIPS Agreement. This allows members to decide the level of requirement for acquiring an IPR on the plant variety and the extent of the same. 
See: Pratyush Jhunjhunwala (2009): Analysis of Article 27(3) (b) of TRIPs-the Content and Implications of the IP Protection on Plant Varieties. American Journal of Economics and Business Administration 1 (4): 313-319, 2009