Graduate Studies


Date of this Version



A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agronomy, Under the Supervision of Professor George L. Graef. Lincoln, Nebraska: April, 2013

Copyright (c) 2013 Thomas J. O’Brien


Bean pod mottle virus (BPMV) can cause yield loss up to 52% in soybean [Glycine max (L.) Merr.] throughout most of the US soybean growing regions. No BPMV resistance genes have been identified, but quantitative trait loci (QTL) associated with BPMV relative virus antigen (RVA) levels were identified in a soybean recombinant inbred line (RIL) population, suggesting possible restriction of virus replication or distribution within the plant. The objectives of this study were to evaluate effects of BPMV infection on yield and agronomic traits of soybean genotypes that differed for RVA level, and to confirm QTL related to RVA. Six RILs were selected from each tail of the distribution for RVA and evaluated for response to infection with a BPMV subgroup I isolate in a randomized complete block design that included BPMV-infected and non-infected plots. The experiment was grown in three environments in each of two years. Genotype information using a 1536 SNP assay was conducted on the parents and RILs. Phenotypes for QTL analysis included mean ELISA OD values for each RIL, leaf scores of foliar symptoms, and difference in seed yield between BPMV infected and non-infected plots. Yield of BPMV-infected plots averaged 11.4% less than non-infected plots. There was no difference between the high-RVA class and the low-RVA class in response to BPMV infection; classification based on RVA was not repeatable. Two QTLs related to leaf score and ELISA OD were identified on chromosomes 3 and 19 in the same regions as RVA QTL identified in the previous study. A key finding in this research is the identification a QTL associated with yield in the presence of BPMV. Five lines demonstrated no difference in yield between inoculated and non-inoculated plots. The QTL mapped on chromosome 14 near underlying genes related to metabolism and defense related genes. The evidence for tolerance to BPMV in these lines and the underlying genetic mechanisms deserve further study.

Advisor: George L. Graef