UC1 is a celery, Apium graveolens L., breeding line segregating for resistance to Fusarium yellows, a disease caused by the pathogen Fusarium oxysporum Schlecht., f. sp. apii, race 2, prevalent in the soils of California. The inheritance of the disease reaction has been studied by Orton et al. (1). Resistance seems to be dominant over susceptibility and highly heritable under greenhouse screening conditions. The segregation ratios observed, however, were not consistent enough to determine the number of genes involved. The principal value of the line should be as a source of resistant plants that can be obtained by making single plant selections in areas where the disease is present, or by screening procedures in the greenhouse. The resistant plants derived from UC1 will need further improvement for hoticultural type in order to obtain Fusarium yellows resistant commercial cultivars.