Location: Plant Science Research2013 Annual Report
1a. Objectives (from AD-416):
Map abiotic resistance genes in soybean for iron deficiency chlorosis, drought, salt stress, aluminum tolerance, and ozone tolerance.
1b. Approach (from AD-416):
Approximately 200 random inbred lines at the F5 stage are ready for seed increase during the summer of 2010 to generate the seed stocks that will be used as material for subsequent evaluations of environmental stress resistance. DNA extraction will be performed and SNP markers will be generated for each random inbred line of the population. A linkage map for the population will be constructed from the DNA data. The population will be evaluated for drought, iron deficiency chlorosis, toxic soil aluminum, salt, and atmospheric ozone pollution, the association of each trait with DNA markers (QTL analysis) will be performed. Independent preliminary research conducted by USDA-ARS in Raleigh, NC, and by the University of Minnesota identified a family of soybean genotypes from Fiskeby, Sweden, that are resistant or partially resistant to drought, iron deficiency chlorosis, toxic soil aluminum, salt, and atmospheric ozone pollution. A population developed from hybridization of Fiskeby III (representing the stress resistance of the Fiskeby soybean family) with Mandarin (Ottawa) (susceptible to drought, ozone, salt, and iron deficiency chlorosis, but resistant to aluminum) will be used to map resistance genes. The original hybridization was made in 2006 and seed of the resulting population were advanced by single seed descent.
3. Progress Report:
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 240 recombinant inbred lines (RILs) has been developed from a cross between tolerant (Fiskeby III) and sensitive (Mandarin Ottawa) genotypes. Each RIL will be assessed for response to each abiotic stress factor and these phenotypic data combined with DNA marker data to construct linkage maps for each factor. Screening the population for iron deficiency chlorosis in Minnesota field plots was completed. Data from 2011 and 2012 are being analyzed in preparation for QTL analysis. Data from both 2011 and 2012 showed significant segregation within the population. Data are being analyzed and formatted for QTL analysis. Programming code for the QTL analyses written for R/QTL to conduct ozone analysis is being adapted for iron deficiency chlorosis. Weather permitted collection of wilting scores in Minnesota field plots during the summer of 2012, so screening of the population for drought was begun. Wilting scores were collected on two dates (July 5 and July 16) before rain events and confounding differences in maturity prevented further readings. On a scale of “1” (no wilting) to 5 (dead plant), scores for the tolerant Fiskeby III parent ranged from 1-2 and the scores for the sensitive Mandarin (Ottawa) parent ranged from 3-4. The RILs had scores that ranged from 1-4, suggesting that identification of QTL for drought in this population will be possible. Seed from the early maturing lines in the population were harvested from Minnesota field plots to maintain seeds supplies.