DISTRIBUTION OF HETERODERA-GLYCINES RACES IN BRAZIL

Soybean cyst nematode, Heterodera glycines, populations were obtained from the states of Goias, Mate Grosso, Mate Grosso do Sul, and Minas Gerais in 1993 from infested fields and greenhouse cultures. Collections were brought under quarantine to Urbana, Illinois for race identification. Nematodes were cultured on 'Lee 68' soybean, and races were identified using 'Lee 68' as the susceptible host and the soybeans 'Pickett 71', 'Peking', PI88.788, and PI90.763 as differential hosts. Plants were inoculated with second-stage juveniles and after approximately 1 month, numbers of white females that had developed on each plant were determined. A female index (FI = [{(x) over bar of females that developed on the differential}/{(x) over bar of females that developed on Lee 68}] x 100) was calculated for each differential soybean line and a race was designated for each population. Races 2, 3, and 5 were identified in collections obtained in Mate Grosso. Races 3 and 14 were identified in collections from Goias. Races 3, 4, 10, and 14 occurred in Mate Grosso do Sul. Race 3 was the only race identified in collections obtained in Minas Gerais.