Change Title of Administrator Backend

To change the title in joomla administrator backend login screen, which looks like "Joomla! Administration Login", the steps are :

1. Find the file /joomla_path/administrator/language/en-GB/en-GB.ini.
2. Then search for the text "Joomla! Administration Login", 
3. Replace the text to the right side of the equal sign to anything you like.