| Abstract: | Aggressiveness and reproduction differed among four geographical populations of M. arenaria on six soybean cultivars in field microplots. These differences were consistent over 3 years. The populations did not differ in virulence; i.e., population by cultivar interactions were not significant. Perineal pattern morphology, the North Carolina differential host test, chromosome counts of immature oocytes, and esterase phenotypes confirmed that the four populations were M. arenaria. Three populations were host race 2 and one population was host race 1. |
