Remove post title from Genesis breadcrumb (assumed on single.php, so limited possibilities). Completely untested.

gistfile1.php

<?php

add_filter( 'genesis_single_crumb', 'gj_single_crumb', 10, 2 );
/**
 * Remove Post Title from Breadcrumb.
 * 
 * Takes a substring of crumb, starting at 0, with a length of up to the last occurrence of the 
 * (start of the) separator string.
 */
function gj_single_crumb( $crumb, $args ) {
	return substr( $crumb, 0, strrpos( $crumb, $args['sep'] ) );
}