LOS ANGELES (Reuters) - Hemlock Semiconductor Group said on Monday it will lay off about 400 workers in Tennessee and Michigan due to a global glut of polysilicon and the threat of tariffs on its products sold in China.

Hemlock is a major producer of polysilicon, the raw material used in most photovoltaic solar panels. It is a joint venture between Dow Corning Corp , Shin-Etsu Handotai and Mitsubishi Materials Corp <5711.T>.

"The threat of tariffs on U.S. polysilicon imported into China has significantly decreased orders from China, which is home to one of the largest markets for our products," Hemlock President Andrew Tometich said in a statement.

The job cuts will affect 300 employees in Tennessee and 100 in Michigan, Hemlock said.

(Reporting by Nichola Groom; Editing by Jeffrey Benkoe)