Wheat prices from the Chicago exchange extended losses on Thursday as very weak US export figures weighed on prices. With the US dollar significantly stronger against the domestic south American currencies such as the Brazilian real and the Argentinian peso, US grain exports have been extremely uncompetitive this year.In Europe, wheat prices were supported by the return of Egypt to the market following the dispute earlier this year over ergot levels in wheat shipments caused a 60,000t cargo of wheat to be rejected by the Egyptian grain authority GASC.