Reaction of soybean cultivars to root-knot nematode Meloidogyne javanica

CORONEL, N; PLOPER, L.D.; JALDO, H; GÁLVEZ, M R

Foz do Iguassú

Conferencia; VII World Soybean Research Conference (VII WSRC).; 2004

Embrapa SOJA y WSRC Continuing Committee

Root-knot nematodes, M. javanica and M. incognita, have been reported in several soybean areas of Argentina. These nematodes can cause stunting of soybean plants and economic losses when fields are heavily infested. The use of nematode-resistant cultivars can reduce yield losses due to these nematodes.  The objective of the research was to determine the reaction of commercial soybean cultivars to M. javanica.  An experiment was conducted during the 2002/03 growing season in La Cocha, Tucumán, in a field naturally infested with M. javanica.  Thirty-eight cultivars were evaluated using a randomized complete block design with three replications.  Each plot consisted of four rows 5 m long and 0.5 m apart. When plants had reached the R5 stage of development, five plants of the two central rows in each plot were rated for galling on a 0-10 scale (0= no galls; 10= maximum galls) (Bridge & Page, 1980).  All soybean cultivars were galled, but they differed in root-gall indices. A 5409 RG, Nueva Mercedes 70 RR, and Mágica 7.3 RR had the lowest root gall indices (2.4 to 2.7). Based on their high gall indices (6 to 7) the cultivars RA 605, A 7636 RG, RA 505 and DM 5800 RR were considered the most susceptible of this group to M. javanica. The remaining cultivars showed intermediate levels of gall indices (3.1 to 5.9).