DUBLIN, Ireland — Guinness beer owner Diageo PLC rattled an Irish icon Friday, announcing plans to lay off more than half of its brewery workers, close two breweries and shift most beer production to a new, high-tech plant in the Dublin suburbs by 2013

The British beverage company decided not to close the landmark Guinness brewery, one of Dublin's oldest businesses and a top tourist attraction, after concluding this would do too much damage to its brand image and customer sentiment.

Half of the riverside St. James' Gate site will be sold for private development, and the volume of Guinness brewed there will be cut by about a third _ to about 500 million pints annually. This will exclusively supply the Irish and British markets, where demand has slipped over the past decade in line with pubgoers' diversifying tastes