Virulence of Meloidogyne incognita populations and Meloidogyne enterolobii on resistant cucurbitaceous and solanaceous plant genotypes

Root-knot nematodes (Meloidogyne spp.) cause extensive damage to tomato and cucurbit crops in protected cultivation systems. An environmentally benign solution for nematode control is the use of plant resistance that mitigates yield losses and reduces the Meloidogyne population in the soil. A collection of three tomato and six cucumber rootstocks was tested for resistance against eight Meloidogyne incognita populations (with different levels of virulence) in comparison with the susceptible variety Moneymaker and the resistant varieties Phantasia or Oskar. In addition, M. enterolobii was included in these experiments to evaluate the response of the tomato and cucumber plant genotypes. Tests were both conducted in a greenhouse or growth chamber and evaluated after completion of one reproduction cycle. The correlation of plant responses to Meloidogyne populations from the different experiments showed significant relationships for 13 and 20 out of 36 combinations for the parameters gall index and number of egg masses per root system, respectively. In particular, two a-virulent reference populations showed significant positive relationships for both parameters, resulting in the same ranking of tested plant genotypes across test systems. Conversely, plant genotypes showed different responses when inoculated with virulent populations of M. incognita or M. enterolobii. Some of the plant genotypes tested showed potential for use in Meloidogyne spp. management strategies. However, cucumber plant genotypes seemed more suitable than tomato genotypes. Furthermore, some of the tested cucumber rootstocks were less sensitive when challenged with M. enterolobii in pot experiments.