By Wendy Pugh

Feb. 16 (Bloomberg) -- Australia, the world’s fourth- largest wheat exporter, trimmed its forecast for the recently harvested wheat crop by 1.5 percent after a heatwave last year was followed by heavy rain in southeastern areas.

Output may be 21.66 million metric tons in 2009-10, compared with a December estimate of 21.99 million tons, the Australian Bureau of Agricultural and Resource Economics said today in an e-mailed report. Production in the previous season was 20.9 million tons, the bureau said.

The government commodity forecaster in December cut the wheat crop estimate by 3 percent because of adverse weather conditions. Farmers typically plant wheat between April and June with harvesting completed by January.

“Production in New South Wales and Queensland was affected by a poor spring,” the bureau said. “Extreme heat followed by heavy rainfall also affected grain quality and yields of later planted crops in Victoria and South Australia.”

The forecast for 2009-10 cotton output was little changed at 371,000 tons compared with the previous forecast of 374,000 tons.

The rice production estimate was increased to 175,000 tons from 165,000 tons and the sorghum crop estimate was reduced to 1.26 million tons from 1.59 million tons.