BEIJING - China's output of summer grain crops, mainly winter wheat and early-season rice, is likely to hit a record high this year, an agriculture official said Thursday.

As of Wednesday, China had harvested 318 million mu (21.2 million hectares) of winter wheat, according to Chen Mengshan, a spokesman from the Ministry of Agriculture.

"Based on current information, China's summer grain output will hit a new high and winter wheat yields will see the ninth consecutive year of growth," he said.

All of the 11 major grain-growing provinces had reported growth in yields, he added.

The acreage of summer grain crops was estimated at 415 million mu this year, an increase of 1.98 million mu from a year earlier, Chen said. Summer grain output accounts for about 25 percent of China's grain yields for the full year.

He said the haul of summer grain has laid a foundation for the entire year's grain harvest, but he added China still faces a range of challenges to ensure growth in autumn grain yields, including natural disasters and biohazards.

The country's grain output hit a high of 571.21 million tons in 2011, marking eight consecutive years of growth.