Meloidogyne arenaria, Chitwood race 1 (rootknot nematode [RKN]), damage to peanut roots and pods causes significant economic loss in infested fields. A gene for nematode resistance, Rma(resistance to M. arenaria), from Arachis cardenasii (a wild peanutrelative), has been introgressed into cultivated peanut through either interspecific hybridization involving a synthetic tetraploid (Arachis batizocoi × [A.cardenasii×Arachis diogoi]) crossed with A.hypogaea or a hexaploid introgression pathway (A. hypogaea × A. cardenasii). The synthetic tetraploid approach, using ‘Florunner’ as the recurrent female parent to introgress Rma, has yielded the resistant cultivars COAN and Nema-TAM. The introgressed region carrying Rma has been found to be collinear with a portion of chromosome 9A and is shared with Tifguard, a high-yielding elite cultivar with near immunity to RKN and high resistance to tomato spotted wilt virus (TSWV).