|Pawlowski, Michelle - University Of Illinois|
|Hill, Curt - University Of Illinois|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2014
Publication Date: 1/7/2015
Citation: Pawlowski, M.L., Hill, C.B., Hartman, G.L. 2015. Resistance to charcoal rot identified in ancestral soybean germplasm. Crop Science. 55:1230-1235. DOI: 10.2135/cropsci2014.10.0687.
Interpretive Summary: Charcoal rot is caused by a fungal pathogen that resides in the soil throughout the soybean growing regions in the United States. The disease is economically important on soybean and other crops including maize, sorghum, and sunflowers. Without effective cultural or chemical options to control charcoal rot in soybean, finding sources of genetic resistance is of high interest. In this study, 70 ancestral soybean genotypes were screened for resistance to the fungus under controlled greenhouse conditions. A series of experiments was completed and three soybean genotypes were found to have higher levels of resistance than the resistant check used for comparison. These sources of resistance will be useful as parents for developing soybean cultivars with charcoal rot resistance. This report will be of interest to soybean pathologists, soybean breeders, and other soybean scientists interested in increasing soybean resistance to this disease which would benefit soybean farmers.
Technical Abstract: Charcoal rot, caused by the fungal pathogen Macrophomina phaseolina, is an economically important disease on soybean and other crops including maize, sorghum, and sunflowers. Without effective cultural or chemical options to control charcoal rot in soybean, finding sources of genetic resistance is of high interest. In this study, 70 ancestral soybean genotypes were screened for resistance to M. phaseolina using a cut-stem inoculation technique under controlled greenhouse conditions. Lesion progression on the stems in the first experiment was measured 7 to 15 days after inoculation. Three follow-up experiments were conducted to select and confirm the genotypes with the strongest partial resistance. Two experiments evaluated lesion lengths and the third experiment evaluated seedling survival. In the two experiments measuring lesion lengths, PI 548302 (42 and 38 mm) and PI 548414 (36 and 52 mm) had significantly shorter lesion lengths than the moderately resistant genotype, DT97-4290 (58 and 87 mm). In the last experiment, percent survival of PI 548414 (88%), PI 548302 (81%), and PI 548178 (66%) were significantly higher than survival of DT97-4290 (32%). These three genotypes will be useful as parents for developing soybean cultivars with charcoal rot resistance.