Interaction Effects of Citrus Rootstocks, Salinity and Tylenchulus semipenetrans Parasitism on Osmotically Active Ions

Abstract

High densities of Tylenchulus semipenetrans and slow decline symptoms are dominant in citrus‐producing areas with high salinity. Currently, no commercial citrus rootstock is both nematode‐resistant and salt‐tolerant. Interaction effects of citrus rootstocks, salinity and T. semipenetrans were evaluated for the partitioning of salinity ions (Cl and Na) and K in microplots. Treatments comprised six citrus rootstocks with wide ranges of salt tolerance, 0 and 3 mols NaCl + 0.25 mols CaCl2 l−1 water and 0 and 856 300 nematodes. At harvest, eight months after salinity treatments, the three–factor interaction was significant (P=0.05) for the alteration in the partitioning of salinity ions and K. Nematodes generally increased salinity ions in leaves and reduced salinity ions in roots and K in both leaves and roots. Thus, management of nematodes is critical in areas with salinity problems.