archive.php

<?php

/**
 * Category Subtitle
 *
 */
function be_category_subtitle() {
	
	// Make sure this is a category archive
	if( ! is_category() )
		return;
		
	
	$category = get_term_by( 'slug', get_query_var( 'category_name' ), 'category' );
	$subtitle = esc_html( get_option( 'category_' . $category->term_id . '_be_subtitle' ) );
	if( $subtitle )
		echo '<p class="subtitle">' . $subtitle . '</p>';
		
}
add_action( 'genesis_before_loop', 'be_category_subtitle' );