Suzanne

For Genesis child themes that output HTML5 only.
This plugin adds an entry field just below the title field on all post, 
page and custom post type edit screens. It allows you to specify a 
subtitle for the content and then outputs the result in an H2 tag just 
under the entry-title where you’d expect to find it.
This plugin is for use with Genesis HTML5 child themes only because it 
uses the hook, genesis_entry_header to position the output after the 
title but before the post-info.

Genesis Subtitles

For Genesis child themes that output HTML5 only.

HasanulBanna

This plugin creates an option to enter sub heading for pages and posts. You can display the sub title in your theme by using the
 
Developed by <a href="http://coregenie.com/" rel="nofollow ugc">Coregenie Technologies</a>
Coded By <a href="http://hasanulbanna.com/" rel="nofollow ugc">BANNA360</a>

Subtitle 360

This plugin creates an option to enter sub heading for pages and posts. You can display the sub title in your theme by using the

Genesis Subtitles vs Subtitle 360