BERLIN (Reuters) - Chancellor Angela Merkel s conservatives widened their lead over the Social Democrats following a television debate in which Merkel came across as more convincing and reliable than her SPD challenger Martin Schulz, a poll showed on Thursday. The weekly survey by Infratest dimap for ARD television showed support for Merkel s CDU/CSU bloc holding steady at 37 percent while the SPD dropped two percentage points to 21 percent - their lowest reading in the poll since early January. The pollster questioned 1,503 voters from Monday to Wednesday, meaning the survey was the first fully conducted after Sunday s television debate in which hardly any policy differences emerged between Merkel and Schulz. The anti-immigration, euro-hostile AfD came in unchanged at 11 percent, making it the third-strongest political force. The radical Left followed with 10 percent, up 1 point. The business-friendly FDP scored 9 percent, also up 1 point, while the environmental Greens were unchanged at 8 percent. The polls indicated two parties FDP and the AfD should enter the Bundestag as they look set to beat the 5-percent threshold. The fractured political landscape could make it hard to form a viable alliance other than the current grand coalition between Merkel s CDU/CSU and the SPD. Another scenario could be a tricky three-way  Jamaica  coalition between Merkel s conservatives, the FDP and the Greens, though such a broad alliance has never been tested on the federal level before. 