Despite “some progress” in recent months, the United States “still has a number of concerns,” said Nefeterius Akeli McPherson, a spokeswoman for the U.S. trade representative. They include “a substantial backlog of pending biotech applications, and bans adopted by individual E.U. member states on biotech products approved at the E.U. level.”

The reality remains that the European Union still produces few genetically modified crops.

The United States, Brazil, Argentina, India and Canada are the top five producers in terms of land under cultivation. The European Union, with 27 member nations, is the 14th largest, just after Burkina Faso.

A key factor behind the proposed change in Europe is a growing frustration in Brussels with the current system, under which meetings between government officials and ministers routinely end in deadlock. That forces unelected officials at the European Commission to make the final decision on authorizing biotech products — and to take the heat.

The commission has found itself repeatedly pressured on one side by the United States and the W.T.O. to follow the recommendations of its own scientific authorities and enforce the use of approved products and on the other by countries like Austria and environmental groups that believe the E.U. authorities are too eager to promote newfangled technologies.

Under the new proposals, the commission would continue to make the approvals itself but leave it to members and local and regional authorities to decide what they want to grow at home.

But whether the new rules will win the necessary approval from E.U. governments and the European Parliament still is unclear.

In an unlikely alliance, the Austrian and Dutch governments first made the proposal back in 2008.

The Dutch were eager to ease tensions over biotech crops with the United States and other trading partners, and to ensure continuing imports of animal feeds that contain biotech products.