Reverse the post order on the page_blog.php template on the Genesis Framework.

reverse-post-order-blog-template.php

<?php
add_filter( 'genesis_custom_loop_args', 'prefix_reverse_blog_template_order' );
/**
 * Reverse Post Order on the page_blog.php
 * template on the Genesis Framework
 *
 * @author FAT Media
 * @link http://youneedfat.com/reverse-post-order-genesis-framework/
 *
 */
function prefix_reverse_blog_template_order ( $args ) {
	// Only change the args for the blog template.
	if ( is_page_template( 'page_blog.php' ) ) {
		$args['orderby'] = 'date';
		$args['order'] = 'ASC';
		return $args;
	}
}

A full explanation of this code as well as some context for why it might not be such a great idea can be found on our blog: How to reverse the post order using the Genesis Framework.