MOGADISHU - Ethiopian and Somali troops captured a key Islamist militant stronghold in Somalia on Wednesday, as the rebels left their positions, a regional government official and residents said. The loss of Baidoa in central Somalia is a major blow for the al Qaeda-backed al Shabaab rebel group which is also battling Kenyan troops to hold on to territory in southern Somalia and against African peacekeepers in pockets of the capital. “We have taken Baidoa. There was no resistance from al Shabaab,” said Abdifatah Mohamed Gesey, a senior commander of the advancing Somali government soldiers.