A team of scientists from the Agricultural Research Service (ARS) and universities have introduced two new oat germplasm lines, CDL-111 and CDL-167, to combat the crown rust fungus, which can cause up to 50% grain yield loss in oat crops. These lines were developed using a plant breeding strategy called 'gene stacking' or 'pyramiding', which involves crossing a cultivated oat variety with wild relatives to obtain 'adult plant resistance'. After being subjected to intense disease pressure, these lines consistently outperformed others. They are now available for use in variety development programs, potentially extending the productive life of oat varieties and reducing the need for chemical fungicides.