Seeds from four citrus genotypes including sour orange, Bitters-C22 citrandarin, Sarawak pummelo x Rio Red grapefruit, and Sarawak pummelo x Bower mandarin were exposed to high amounts of Phytophthora nicotianae to screen for tolerance. Inoculation of pre-germinated seeds (PGIS) and non-pre-germinated seeds (NPGIS) was carried out. The average P. nicotianae propagule counts from the soil samples where these seedlings were raised ranged from 424-1361 cfu/cm³. The proportion of live/dead plants was recorded at eleven months post-inoculation. Sarawak x Bower performed significantly better compared to other genotyes. Evaluation of the rootstocks eighteen months post-inoculation resulted in only one surviving sour orange plant which suggests potential genotype resistance.