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Identification of Soybean Accessions Resistant to Cercospora sojina by Field Screening, Molecular Markers, and Phenotyping
Author(s) -
Mengistu Alemu,
Bond Jason,
Mian Rouf,
Nelson Randall,
Shan Grover,
Wrather Allen
Publication year - 2011
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2010.09.0529
Subject(s) - biology , cultivar , leaf spot , locus (genetics) , allele , horticulture , breeding program , botany , veterinary medicine , genetics , gene , medicine
Frogeye leaf spot (FLS) of soybean [ Glycine max (L.) Merr.], caused by Cercospora sojina K. Hara, has been a problem in the southern United States for many years. Cultivars resistant to FLS have been developed for planting in this area, and resistance in many of these cultivars is conditioned by the Rcs3 allele at the Rcs3 locus, which provides immunity to all known races of the pathogen. Frogeye leaf spot has recently become a greater problem in the northern United States, and few C. sojina resistant cultivars and breeding lines adapted to this area have been identified. The objectives of this study were to (i) identify maturity group (MG) 00 to VII accessions resistant to C. sojina race 11 by field screening at multiple locations over years and (ii) determine if FLS resistance in these accessions is likely to be conditioned by the Rcs3 allele. A total of 522 accessions were evaluated for reaction to race 11 in field trials in Missouri and Illinois during 2006 and 2007, and 84 of these lines did not develop symptoms of FLS and were field screened for reaction to natural inoculum in Tennessee during 2008. Nine accessions of the 84 lines were susceptible. The remaining 75 were subsequently tested for the possible presence of Rcs3 using five molecular markers located within 2 cM of the gene. Of these 75 accessions, only PI 437726, PI 438302B, and PI 494851 had the Rcs3 haplotype of the cultivar Davis, the source of Rcs3 The soybean accessions predicted not to have the Rcs3 allele and with no FLS symptoms in field trials may also be useful in developing soybean cultivars with resistance to FLS.