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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVEMENT OF PEST RESISTANCE AND QUALITY TRAITS OF SOYBEAN

Location: Corn, Soybean and Wheat Quality Research Unit

Title: Identification of Soybean Genotypes Resistant to Cercospora sojina by Field Screening and Molecular Markers

Authors
item Mian, Rouf
item Bond, Jason - SOUTHERN ILLINOIS UNIV
item Joobeur, Tarek - THE OHIO STATE UNIVERSITY
item Mengistu, Alemu
item Weibold, William - UNIVERSITY OF MISSOURI
item Grover, Shannon - UNIVERSITY OF MISSOURI
item Wrather, Allen - UNIVERSITY OF MISSOURI

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 18, 2008
Publication Date: April 1, 2009
Repository URL: http://hdl.handle.net/10113/32224
Citation: Mian, R.M., Bond, J., Joobeur, T., Mengistu, A., Weibold, W., Grover, S., Wrather, A. 2009. Identification of Soybean Genotypes Resistant to Cercospora sojina by Field Screening and Molecular Markers. Plant Disease. 93:408-411.

Interpretive Summary: Frogeye leaf spot (FLS) of soybean is a common disease in many soybean producing countries of the world, including southern USA. FLS has recently become a greater problem in northern USA, including Ohio. Cultivars resistant to FLS are available for planting in the southern U.S., and resistance in many of the cultivars is conditioned by the Rcs3 gene. This gene conditions for immunity to all known races and isolates of the pathogen. Few soybean genotypes (cultivars and breeding lines) adapted for planting in the north U.S. have known resistance to FLS. The objectives of this project were, 1) to identify maturity group (MG) III, IV, and V soybean genotypes resistant to C. sojina race 4 by field screening at multiple locations over years, and 2) to determine if FLS resistance in these genotypes is likely to be conditioned by the Rcs3 gene using molecular markers. Of 1350 different genotypes evaluated for resistance to race 4 in field trials, 13 MG III, 45 MG IV, and 15 MG V genotypes exhibited no FLS symptoms. Of these, 54 were subsequently tested for the possible presence of Rcs3 using five molecular markers tightly linked with the gene. None of the MG III genotypes tested had the Rcs3 haplotype of cultivar Davis, source of Rcs3, six of the MG IV genotypes, and seven of the MG V genotypes had the Rcs3 haplotype. Use of molecular markers for improving frogeye leaf spot resistance of soybean conditioned by the Rcs3 gene is a practical option now available to soybean breeders.

Technical Abstract: Frogeye leaf spot (FLS) of soybean, caused by Cercospora sojina K. Hara, has been a problem in the southern U.S. for many years and has recently become a greater problem in the northern U.S. Cultivars resistant to FLS have been developed for planting in the southern U.S., and resistance in many of these cultivars is conditioned by the Rcs3 gene. This gene conditions for immunity to all known races and isolates of the pathogen. Few soybean genotypes (cultivars and breeding lines) adapted for planting in the north U.S. have known resistance to FLS. The objectives of this project were, 1) to identify maturity group (MG) III, IV, and V soybean genotypes resistant to C. sojina race 4 by field screening at multiple locations over years, and 2) to determine if FLS resistance in these genotypes is likely to be conditioned by the Rcs3 gene using molecular markers. Of 1350 different genotypes evaluated for resistance to race 4 in field trials, 13 MG III, 45 MG IV, and 15 MG V genotypes exhibited no FLS symptoms. Of these, 54 were subsequently tested for the possible presence of Rcs3 using five molecular markers located within 2 centimorgan (cM) of the gene. None of the MG III genotypes tested had the Rcs3 haplotype of cultivar Davis, source of Rcs3, six of the MG IV genotypes, and seven of the MG V genotypes had the Rcs3 haplotype. The soybean genotypes predicted to have the Rcs3 gene and other genotypes with no FLS symptoms in field trials may be useful in breeding soybean cultivars with broad resistance to FLS and adapted to the northern USA.

Last Modified: 4/20/2014
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