Developed and developing nations need to solve contentious agricultural issues such as farm subsidies for the success of global trade talks, U.S. trade chief Rob Portman said on Saturday, Reuters reported. Leading World Trade Organisation (WTO) members failed at meetings this week in London and Geneva to make headway in agriculture, industrial goods and services -- three key areas of the negotiations. Countries no longer expect to agree on a plan for finishing the four-year-old Doha Round of world trade talks when they hold a WTO ministerial meeting next month in Hong Kong. Portman is in India to discuss how to advance the troubled WTO talks and strengthen bilateral trade ties. "Unless we can solve this problem on agriculture, it is difficult to move on and have a successful conclusion of other very important aspects of this round, including reduction in industrial tariffs," Portman told Indian businessmen. After his talks with Indian Commerce Minister Kamal Nath, Portman said he was not lowering expectations of the Doha round of talks. "We shall not be lowering the expectations or lowering the ambition in the round but second with regard to Hong Kong, we still don't know whether we will be able to have the kind of framework we hoped," Portman told reporters. --More 1804 Local Time 1504 GMT