Dow AgroSciences' decision to severely restrict U.S. introduction of its Enlist genetically modified crops and herbicide - billed as the company's most important product launch ever - came after extensive talks with U.S. grain leaders who fear roiling trade with China, a company executive said Thursday.

The deep involvement of the grain industry in defining a GMO crop launch and the controls on that launch underscore the lengths U.S. companies are going to avoid angering China.

Over the last year China has shown reluctance to approve new GMO grain for import and has rejected more than 1 million tonnes of U.S. corn containing traces of unapproved GMO traits.

Dow AgroSciences' application for Chinese approval of its Enlist genetically modified corn has languished for about two years. Its Enlist soybeans are also awaiting approval. Both are genetically engineered to withstand treatments of Dow's new Enlist Duo herbicide.

"We want to make sure that we respect their (China's) process," Joe Vertin, Dow AgroSciences' global leader for Enlist, said in an interview.

Vertin said after the company received U.S. regulatory approvals this fall it held talks with national corn and soybean grower groups, grain trading groups and others about how to proceed.

The agricultural unit of Dow Chemical evaluated several proposals before coming up with what Vertin called a "unique" strategy.

That plan, unveiled Wednesday, allows only for seed production of its new Enlist soybeans and sales of Enlist corn seed only to farmers who will feed the harvested grain to livestock on their farms and agree to have the process audited. Enlist Duo herbicide will be sold for use on those crops.

The program is for 2015 and will be re-evaluated for 2016 depending on China's position.

Vertin would not specify the acreage targeted for the launch. But he said there is a significant amount of grain that stays on farm for feed use, and the company is still optimistic for broad adoption at some point.

"As we look at any biotech trait... it's a gradual process," he said.

Dow's program is stricter than that of Syngenta AG , which also is trying what the industry calls a "stewarded launch."

Syngenta is requiring farmers who plant its Agrisure Duracade GMO corn to feed the harvest to livestock or deliver it to a facility that will not export it to China.