获取父类别

$_cat = new Mage_Catalog_Block_Navigation();
$curent_cat = $_cat->getCurrentCategory();
$curent_cat_id = $curent_cat->getId();
$parentId=Mage::getModel('catalog/category')->load($curent_cat_id)->getParentId();
$parent = Mage::getModel('catalog/category')->load($parentId);
$categorydaddy = $parent->getName();