Dry bean cultivars with the potential for use in potato–dry bean crop rotation systems for managing root-knot nematodes in South Africa

Abstract

Potato (Solanum tuberosum) cultivars are highly susceptible to the root-knot (Meloidogyne spp.) nematodes, with the preferred nematode management strategy being rotation using nematode-resistant crops. Most commercial potato- producing farmers prefer high-yielding, but low-input leguminous crops for use in potato crop-rotation systems intended to manage Meloidogyne spp. A study was conducted to screen 11 commonly used dry bean (Phaseolus vulgaris) cultivars in potato rotation systems for managing population densities of Meloidogyne species. Three screening trials, each for M. javanica, M. incognita race 2 and M. incognita race 4, were conducted under greenhouse conditions. After validation in time, at 56 d after inoculation, the reproductive potential values of Meloidogyne spp. on test dry bean cultivars suggested that the cultivars were hosts, except for the cultivar ‘Kleinwit’, which was a non-host to M. incognita race 2 and M. incognita race 4, but host to M. javanica. In conclusion, except for ‘Kleinwit’, most dry bean cultivars used for managing Meloidogyne species in potato–dry bean crop-rotation systems in South Africa are hosts and are therefore not fit for the intended purpose since host plants promote the build-up of nematodes. In addition, ‘Kleinwit’ should be used with caution because it was host to M. javanica.