EVALUATION OF AMARANTHUS SPECIES FOR THEIR HOST SUITABILITY TO THE ROOT-KNOT NEMATODES, MELOIDOGYNE INCOGNITA RACE 2 AND MELOIDOGYNE JAVANICA IN SOUTH AFRICA

Amaranthus, collectively known as amaranth, is a cosmopolitan genus of herbs comprising of approximately 60 species. People around the world value amaranths as a leafy vegetable, cereal and ornamental. It is an excellent source of dietary fibre and minerals. A traditional food plant in Africa, amaranth has the potential to improve nutrition, boost food security, foster rural development and support sustainable land care. Root knot nematodes (Meloidogyne) are major constraints in vegetable production systems, particularly under subsistence-farming conditions in South Africa. The use of host plant resistance could provide farmers with a sustainable option for nematode control in these production systems. This study was conducted to determine whether Meloidogyne incognita race 2 and Meloidogyne javanica resistance is present in locally available Amaranthus species. Nematode parameters used to select for resistance were reproduction factors (Rf) and egg laying females (ELF). Although substantial variation existed among the ten Amaranthus species with regard to the host response parameters measured, none of the species evaluated were immune to M. incognita race 2 and M. javanica. One of the ten species screened, Local 33 had an Rf-value ≤1, when screened against M. incognita race 2, indicating possible resistance to this population of M. incognita race 2. All species were susceptible to the population of M. javanica used in this study.