Disclaimer: Total newbie.

I have a two tables, routes (ruta) and drivers (conductor), each route has an assigned driver so in the route model I created a many2one field linking both tables:

conductor_id = fields.Many2one('produccion.conductor', required=True)
conductor_nombre = fields.Char(related='conductor_id.nombre', string="Conductor")

I can succesfully display the drivers name on a list by adding the conductor_nombre field, however, on a form, the dropdown for the driver field displays the driver ID, how do I make it dispaly the driver´s name only?

<field name="conductor_id"/>