altoona iowa iowa governor say tuesday would big mistake voters nation first presidential contest next month choose ted cruz republican nomination cite u.s. senator opposition biofuel mandate important state republican governor terry branstad say cruz pocket big oil criticize texan opposition renewable fuel standard require u.s. fuel contain minimum amount biofuels include ethanol ethanol major market iowa corn state voters generally support ethanol mandate branstad say cruz big opponent renewable fuel heavily finance big oil ted cruz ahead poll diametrically oppose really care grow opportunity renewable fuel country branstad say branstad speak address iowa renewable fuel summit republican front-runner donald trump also speak late day endorse renewable fuel standard branstad old son eric work political action committee critical cruz ethanol stance governor say would endorse candidate feb. caucus iowa cruz lead trump opinion poll think would big mistake iowa support branstad say cruz know ahead poll poll count one take caucus night think could change then u.s. representative steve king iowa back cruz criticize branstad comment de facto endorsement trump report kay henderson write doina chiacu edit jonathan oatis sap sponsor coverage independently produce staff reuters news agency iowa governor urge caucus-goers say 'no cruz cite 'big oil