Host suitability in soybean cultivars for the reniform nematode, 1999 tests

Two hundred twenty-six soybean cultivars were tested in greenhouse pot experiments during summer 1999 to determine their suitability as hosts for the reniform nematode, Rotylenchulus reniformis. The cultivars included new entries into the Arkansas and Mississippi soybean variety testing programs and entries submitted by extension nematologists from Auburn University and Louisiana State University. Also included in the R. reniformis tests were the resistant cultivars Forrest and Hartwig, the susceptible control Braxton, and fallow infested soil that served as controls. Total number of eggs + nematodes extracted from the soil and roots per pot, reproductive indices (Pf/Pi) based on the number of nematodes extracted from the soil and roots/initial inoculum level, calculated for each cultivar, and the ratio of the Pf/Pi of each cultivar to the Pf/Pi of Forrest are reported. Cultivars with reproduction not significantly different from Forrest were not suitable hosts, whereas those with greater reproductive indices were considered suitable hosts. One of the 12 cultivars of the relative maturity group (RMG) <=4.4 was not a suitable host. For the 4.5 to 4.9 RMG, 24 of 72 cultivars were not suitable hosts, whereas 9 of 41 cultivars in RMG 5.0 to 5.4 were not suitable hosts. In the 5.5 to 5.9 RMG cultivars, 11 of 66 were not suitable hosts; for the 6.0 or greater RMG, 11 of 35 were not suitable hosts. These data will be useful in the selection of soybean cultivars to use in rotation with cotton or other susceptible crops to help control the reniform nematode.