Reaction of soybean cultivars to Heterodera glycines race 5

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

Thirty-one cultivars of soybean were evaluated for their reaction to Heterodera glycines race 5, the soybean cyst nematode. The experiment was conducted in a greenhouse and the nematode population came from infested soils in San Agustín, Tucumán, Argentina. The experiment was arranged in an entirely randomized design with one plant per plot and 7 replications. Each pot held about 250 cm3 of a 1:2 soil: sand mixture.  The cultivar A 8000 RG was used as the susceptible control. Plants of each cultivar were inoculated with approximately 4000 eggs placed into a hole next to the plant. Evaluations were done 28 days after inoculation by counting the number of white females that had developed on each plant. A female index (FI=[{average number of females on the tested cultivar}/{average number of females on the susceptible control}]x 100) was calculated for each soybean cultivar. Reaction of cultivars was determined by the system of classification proposed by Schmitt & Shannon (Crop. Sci. 32: 275-277, 1992): FI= 0-9%, resistant (R); FI= 10-30%, moderately resistant (MR); FI= 31-60%, moderately susceptible (MS); and FI= > 60%, susceptible (S).  PI 437654 and Hartwig were resistant (FI=0%) to H. glycines race 5.  The remaining cultivars evaluated in this experiment were susceptible and moderately susceptible (FI=32-127%).