Reaction of sugarcane genotypes to root-knot nematode parasitism (Meloidogyne javanica and Meloidogyne incognita)

Abstract

Root-knot nematodes (Meloidogyne spp.) can cause a reduction up to 50% in the production of sugarcane (Saccharum spp.). Genetic resistance is considered an important component in the management of nematodes. Therefore, the aim of this study was to evaluate the susceptibility of 12 sugarcane genotypes when subjected to parasitism by Meloidogyne javanica and Meloidogyne incognita under controlled conditions in a plant growth chamber. Four experiments were carried out in randomized blocks with 12 treatments and four replicates for M. javanica and three replicates for M. incognita. The treatments were the sugarcane genotypes: RB966928 (susceptibility pattern), RB026842, RB036168, RB036145, RB036065, RB966229, RB036066, RB036068, RB046209, RB036163, RB036153, and RB036059. Each repetition consisted of a 2-L pot with previously autoclaved substrate (1:1 of sand and soil), and a pre-sprouted seedling was transplanted. From pure populations of M. javanica and M. incognita, approximately 2,000 eggs and eventual J2 were inoculated per pot. After 120 days, the final population of nematodes in the root and soil was counted using an optical light microscope and Peters slide, and the reproduction factor (RF) was calculated. Plants that presented RF < 1 were considered resistant, and plants that presented RF > 1 were considered susceptible. Among the 12 genotypes evaluated, 66% were susceptible to parasitism by M. javanica. The genotypes RB046209, RB036163, RB036153, and RB036059 were classified as resistant to M. javanica parasitism. For the species M. incognita, the susceptible genotypes represented 75% of the total, and the resistant genotypes were RB036163, RB036153, and RB036059.