Identifying Non-Host Sweet Potato Cultivars To Combat Nematodes

The root-knot nematode can cause major financial losses for sweet potato farmers if not managed effectively. Dr Kgabo Pofu and Dr Sunette Laurie of the Agricultural Research Council’s Vegetable and Ornamental Plants Institute, and Prof Phatu Mashela of the Green Technologies Research Centre, University of Limpopo, report on trials of nematode-resistant sweet potato cultivars.

- Prof Phatu Mashela

After the withdrawal of methyl bromide as a pesticide, research efforts in the production and protection of sweet potato have shifted towards the use of nematode-resistant cultivars as an alternative strategy for managing root-knot nematodes of the Meloidogyne genus.

However, successful use of these cultivars demands the accurate identification of Meloidogyne species and races. This, in turn, depends on close collaboration between plant breeders and plant-parasitic nematologists.

Plant-parasitic nematodes are a costly burden in crop production. Omnipresent in nature, they are associated with nearly every important agricultural crop and are a significant constraint on global food security.

Root-knot and reniform (Rotylenchulus spp) nematodes cause an estimated US$2,6 billion (about R45,2 billion) worth of damage to sweet potato crops worldwide every year. In South Africa, the root-knot nematode (Meloidogyne spp), cyst nematode (Heterodera spp and Globodera spp) and lesion nematode (Pratylenchus spp) top the list of the most economically and scientifically important species due to their complex relationship with their host plants, their wide host range and the level of damage caused to the crop following infection.

WHICH CULTIVARS HOST NEMATODES?

Identifying sweet potato cultivars that are tolerant of or resistant to the three