Custom tpl.php render issues I'm in a custom tpl.php file. I'm also highly confused!

This line renders nothing...

render($content['field_subtitle']['0']['#markup']);


This line drops the subtitle as expected but in the Devel_Themer formatting.

kpr($content['field_subtitle']['0']['#markup']);


I'm trying to custom-theme a content type in a custom node.tpl.php file. Everything should work as expected... but, of course... it's not. Any ideas?
It looks like you could use:

print $content['field_subtitle']['0']['#markup'];


or else just

print render($content['field_subtitle']);