China's quarantine authorities have rejected more than 1.2 million metric tons of American corn after detecting an unapproved genetically modified strain in shipments, with buyers shifting to cheaper grain from other markets.

As of June 16, quarantine authorities had detected the MIR 162 strain, one that has yet to be approved by the country's agricultural authorities, in about 1.25 million tons of corn shipped from the US and rejected all of it, said Lu Chunming, spokesman for the General Administration of Quality Supervision, Inspection and Quarantine, at a news conference on Monday.

The MIR 162 strain was first detected in a shipment at a port in Shenzhen, Guangdong province, last October.

Lu said the authorities will continue to monitor the corn strain in its port quarantine. He also reminded domestic corn importers to state specifically in contracts that imports must be in line with Chinese law.

Analysts said the rejection of US corn has prompted the country's corn buyers to shift to other markets.

"One of the major replacement markets is Ukraine," said Feng Lichen, president of yumi.com.cn, a Web platform for corn information.

Feng said a trend is for Chinese companies to purchase land in Ukraine and grow crops there, including corn, before shipping them back home.

Feng noted that the crops grown in Ukraine are all non-GMO strains, which could increase their popularity among domestic importers.

China imported more than 243,000 metric tons of corn from Ukraine from October to May, up from the 24.9 metric tons imported during the same period last year, according to SCI International, a commodity market information service organization, citing customs data.

Meanwhile, the amount of imported corn from the US reached 2.39 million metric tons in the October-May period, down by 0.17 million metric tons.

The China National Grain and Oils Information Center estimated that total imports from Ukraine for the entire year could hit 800,000 metric tons. China also imported 77,936 metric tons of corn from Thailand in February, Reuters reported.

But Feng also warned that the country holds close to 100 million metric tons of corn in buffer stocks and that increasing imports could hamper the protection of domestic farmers' interests.

"A massive increase in the quota of corn imports is unlikely as the country does not currently have a corn shortage," he said.

China's corn import quota currently stands at 7.2 million metric tons.

Feng also said that a decision on the MIR 162 strain, designed to protect plants from insects, is unlikely to be made before August, when a meeting of the biosafety committee under the Ministry of Agriculture is scheduled.

xuwei@chinadaily.com.cn