Host response of five potato cultivars to Meloidogyne nematodes

Potato (Solanum tuberosum L.) is a well-known food crop that is regarded as an important component in the worldwide battle against hunger and malnutrition. Root-knot nematodes (RKN), Meloidogyne species, are a serious limitation in the potato industry. Potato, being a tuberous crop, yield reduction is mainly due to tuber quality and quantity. In order to evaluate the response of five commercial potato cultivars, viz ‘Buffelspoort 1’, ‘Hertha’, ‘Larnoma’, ‘Mnandi’ and ‘Up-to-date’ to two RKN species, viz M. enterolobii and M. javanica; pot experiments were conducted under net house conditions. Ten separate experiments, each with treatments: 0, 500, 1500, 2500 and 3500 eggs + second-stage juveniles (J2), were arranged in a randomized complete block design (RCBD) with five replicates. Fifty-six days after inoculation, nematode effect on plant yield was evaluated. Potato tubers were assessed for root galls, and nematodes reproductive factor (RF) was computed. There were significant differences amongst treatments on the following potato growth parameters: plant height, stem diameter, chlorophyll content, number of tubers and tuber weight in both M. enterolobii and M. javanica (P ≤ 0.05). The RF was above unity (one) in all potato cultivars for both M. enterolobii and M. javanica; with M. enterolobii showing more aggressiveness compared to M. javanica. Further, cultivars ‘Buffelspoort 1’ and ‘Hertha’ showed the highest susceptibility, whilst cultivar ‘Mnandi’ showed the least susceptibility. Infection of potato cultivars by the nematodes had severe effects on growth parameters of all the cultivars. Results suggested that all five commercial potato cultivars were susceptible to M. enterolobii and M. javanica. Thus, there is an urgent need for RKN management intervention in the aforementioned cultivars.