Performance of tomato rootstocks in False Root-knot Nematode (Nacobbus aberrans) infested soil

Abstract

Nacobbus aberrans, known as the "false root-knot nematode", has drawn special attention since it affects large areas of tomato production in Latin America. The aim of this study was to evaluate two rootstocks, Solanum lycopersicon L. var. cerasiforme ´Carolina´ and S. lycopersicon L. ´Maxifort´, onto which S. lycopersicon L. ´Santa Clara´ was grafted. In addition to these, non-grafted ´Santa Clara´ plants were used as control. Grafting was carried out 30 days after sowing, both for scion and for rootstocks. Both the grafted plants and those used as control were grown in a greenhouse on two kind of substrate: without the presence of N. aberrans and inoculated with 5000 eggs. After 60 days of being inoculated, growth parameters, physiological stress indicators, and pathogen reproductive factor were evaluated. The parasitism caused changes in the metabolism of the plants. On grafted plants, f lowering was delayed, and on plants exposed to nematodes such delay was even greater. The reproductive factors of the nematode were 3.68, 5.47 and 2.76 on non-grafted rootstocks, ´Carolina´ and ´Maxifort´, respectively, and they were classified as suscepti ble. The Maxifort rootstock has an invigorating effect on Santa Clara scion. It stimulates the apical growth and shows a great tolerance to the attack of nematodes as indicated by parameters like the accumulation of proline and the damage in the cell membranes. However, N. aberrans reproduces at its roots and increases its population, so its use as rootstocks must be carried out together with other practices that reduce the reproduction factor of the pathogen.