Change the value of each checkbox to term slug instead of name, and change
wp_set_post_terms($pid,array($_POST['genre']),'gen re',true);
To
wp_set_post_terms($pid,(array)$_POST['genre'],'gen re',true);
Change the value of each checkbox to term slug instead of name, and change
wp_set_post_terms($pid,array($_POST['genre']),'gen re',true);
To
wp_set_post_terms($pid,(array)$_POST['genre'],'gen re',true);