* Approval latest step under 100-day China-U.S. trade talks

* Comes after expert biotech committee met in June

* DuPont 'disappointed' its corn trait not included (Recasts, adds statement from Monsanto)

By Dominique Patton

BEIJING, July 18 (Reuters) - Global seeds giants have called for transparent, science-based approvals processes for new crop types after China approved two more genetically modified (GMO) crops for import, but left four others on the waiting list.

China on Monday approved Syngenta's 5307 insect-resistant corn sold under the Agrisure Duracade brand and Monsanto's 87427 glyphosate-resistant corn, sold under the Roundup Ready brand, for a period of three years.

The move was the second in the past month to expand access to biotech seeds as part of Beijing's 100-day trade talks with Washington, and took total approvals to four after Dow Chemical Co's Enlist corn and Monsanto's Vistive Gold soybeans were given the go-ahead last month.

But it leaves four other products owned by Monsanto, DuPont and Dow on a waiting list pending approval.

DuPont was "disappointed" its Pioneer insect-resistant corn was not included, a spokeswoman said in an email. The other three crops are Dow's Enlist soybeans and two alfalfa products developed by Monsanto.

Monsanto also found it "disappointing" that not all six products in the late stage of review received approvals, the company's spokeswoman Christi Dixon said in an statement emailed to Reuters.

"This is inconsistent with numerous scientific conclusions around the world on these same products, as well as with the spirit of the U.S.-China 100-day plan," Monsanto said in the email.

The U.S. industry has repeatedly complained about the lack of transparency in China's biotech review process.

Beijing has in the past held back approvals of imported GMO products amid concerns about anti-GMO sentiment in the country.

DuPont continued to cooperate with Chinese regulators, its spokeswoman said, but added that "global markets should conduct predictable, transparent regulatory reviews based on sound science and be free from political influence".

Monsanto acknowledged the progress made with the latest approvals in its statement but stressed the need for a "predictable, science-based and transparent regulatory approval process in China" to allow new products to reach growers.

Dow's Asia Pacific media relations representative Eileen Zeng could not be immediately reached for comment.

Hopes that all six would get the go-ahead in the second round mounted after the National Biosafety Committee (NBC), a group of experts who advise the government on GMO safety, met late last month to review the products, company executives and experts said.