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Reniform Nematode Reproduction on Soybean in Tests Conducted in 2002

R.T. Robbins, L. Rakes, L.E. Jackson, E.R. Shipe, E.E. Gbur, and D.G. Dombek

ABSTRACT

In 2002 greenhouse pot experiments,127 soybean varieties from the Arkansas and Mississippi variety testing programs and 34 breeding lines from Clemson University were tested to determine their suitability as hosts for the reniform nematode, Rotylenchulus reniformis. The R. reniformis-resistant varieties Forrest and Hartwig, the susceptible variety Braxton, and fallow- R. reniformis-infested soil served as controls. Total number of eggs and nematodes extracted from both the soil and roots from each pot, reproductive indices (RI = Pf/Pi), RI/RI of Forrest (RF), log ratio [log10 (RF + 1)], and RF calculated from log10 (RF + 1) were calculated for each cultivar or breeding line in each test. Varieties with RF’s significantly greater than the RF on Forrest (1.00) were considered suitable hosts for R. reniformis. In the Arkansas and Mississippi variety test 58 of 127 lines had significantly more reproduction than Forrest when the log ratio [log10 (RF + 1)] were compared. In the Clemson test 14 of the 34 Clemson varieties and breeding lines were suitable hosts when the log ratio [log10 (RF + 1)] were compared. Of the 20 Clemson lines not significantly different than Forrest eight were retests from 2001 that agreed with the 2001results, whereas two of the 20 shown to be significantly different in 2001 were not shown to be different in 2002. The last of 11 retests was found to be different than Forrest both years.





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Document last modified July 15, 2003