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Poster: Biology & Disease Mgmt: Genetics of Resistance


Screening soybean germplasm for resistance to multiple Fusarium species
P. OKELLO (1), L. Hyronimus (1), A. Weber (1), A. Singh (2), F. Mathew (1) (1) South Dakota State University, U.S.A.; (2) Iowa State University, U.S.A.

Fusarium root rot caused by multiple Fusarium spp. continue to cause increased soybean [Glycine max L.] yield losses in the United States. Commercial soybean varieties with complete resistance to Fusarium spp. are not available, thus necessitating the need for continued search for sources of resistance. The objective of this study was to identify screen soybean germplasm for resistance to four Fusarium species (F. proliferatum, F. graminearum, F. sporotrichioides, and F. subglutinans), which were identified as aggressive Fusarium spp. based on a preliminary study on soybean in South Dakota. To evaluate soybean germplasm for resistance to the four Fusarium spp., 44 genotypes belonging to maturity groups I from 10 different countries were screened in replicated tests using the inoculum-layer method. Disease severity was evaluated at 14 days after inoculation as a percentage of lesion produced on soybean roots by the causal pathogen. Preliminary results suggests one genotype (PI 603371) had significantly lower disease severity (P ≤ 0.05) than the susceptible check for all the four Fusarium species. This genotype will be useful as a parental material to develop commercial soybean cultivars with resistance to Fusarium species.