The host status of Amaranthus spp. genotypes to Meloidogyne spp. and verification of resistance in genotype Thohoyandou

African leafy vegetables (ALVs) play a crucial role in substituting the diets and household income of local people. Production of ALVs is, however, hampered by plant-parasitic nematodes, particularly Meloidogyne spp. The objectives of this study were: i) to determine the host suitability of 13 Amaranthus genotypes to Meloidogyne incognita and M. javanica in separate greenhouse experiments, and at three on-farm field sites, and ii) to verify resistance exhibited by genotype Thohoyandou, identified in greenhouse screenings, to the two said root-knot nematode species in micro plot studies. Glasshouse screenings for M. incognita showed reproduction factor (Rf) values < 1, indicating resistance, for genotypes Oyaya, Red Stem, Local 33 and Thohoyandou. Only genotypes Red Stem and Thohoyandou had Rf < 1 for M. javanica. Field data showed that genotypes Thohoyandou, Local 33, ACAT Seedfair and Oyaya maintained relatively low population densities of Meloidogyne spp. per 50 g roots at the three experimental sites, while A. cruentus, A. greacizans and A. tricolor, ex Botswana and Applebosch were the most susceptible. For micro plot experiments, values of all reproduction parameters were significantly lower for final population densities of resistant genotype Thohoyandou compared to that of susceptible genotype Arusha when evaluated against M. incognita. For M. javanica, only egg-mass numbers per root system were significantly lower for genotype Thohoyandou compared to those of Arusha. Use of resistant genotype Thohoyandou will benefit producers and can contribute to food security, household income and sustainable crop production.