CANTON, MASS. — William Kussell, president and chief brand officer at Dunkin’ Donuts, will leave the company at the end of the year. With Mr. Kussell’s departure, Nigel Travis, chief executive officer, also will assume the role of Dunkin’ Donuts president. "In the 15 years since Will joined Dunkin’ Donuts, the company has grown from a regional donut chain with about 3,000 stores into the No. 1 coffee and baked goods brand worldwide with more than 8,800 stores in 31 countries," said Mr. Travis, who was named c.e.o. in January. "Among many achievements, Will has played a pivotal role in leading the transformation of Dunkin’ Donuts and the repositioning of the brand through its acclaimed advertising campaign, ‘America Runs on Dunkin.’"