2011 Annual Report
1a.Objectives (from AD-416)
Phenotype a soybean mapping population for environmental stress factors.
1b.Approach (from AD-416)
Random inbred lines (RILs) are nearing final stages of development and 192 RILs will be selected for marker assisted mapping of resistance genes. The RILs will be assayed for single nucleotide polymorphisms to identify markers for mapping. The RILs will be assessed for response to drought, iron deficiency chlorosis, salt stress, aluminum stress, and ozone stress. Injury scores and DNA marker results will be related through QTL analysis.
This project is related to Objective 3 of the parent project to identify soybean germplasm that will contribute to development of stress tolerant cultivars.
The objective of this project is to map stress tolerance genes in soybean for five abiotic stress factors: drought, iron deficiency chlorosis, ozone, salt, and toxic soil aluminum. A mapping population of random inbred lines will be developed from a cross between tolerant (Fiskeby III) and sensitive (Mandarin Ottawa) genotypes. Each random inbred line will be assessed for response to each abiotic stress factor and these phenotypic data combined with deoxyribonucleic acid (DNA) marker data to construct linkage maps for each factor.
The seed increases for the mapping population of 240 random inbred lines were completed during the summer of 2010 in Minnesota and in a 2010-2011 winter nursery in Chile operated by our University of Minnesota cooperator. These seed sources will be used to phenotype the mapping population for abiotic stress response.
The initial screening of the mapping population for ozone response was conducted greenhouse exposure chambers located in Raleigh, North Carolina with the Fiskeby III (ozone-tolerant) and Mandarin Ottawa (ozone-sensitive) parents used as checks. The population exhibited a wide range of foliar injury in response to the ozone treatment. Assessment of the data has begun and plans made for additional experimental replication.
Screenings of the mapping population for both drought and iron deficiency chlorosis responses were begun by our University of Minnesota cooperator at field sites previously identified to exhibit these unique stress factors. The parental lines and other checks specific to the stress of interest were included in replicated field plots. Injury scores are being taken to provide the phenotype data required for mapping studies.
DNA for use in single nucleotide polymorphism (SNP) marker assay was extracted from leaf tissue for approximately 90% of the random inbred lines with the reminder to be completed in fiscal year 2012.