Presentation on theme: "Qualitative and Quantitative Characterization and Mapping of Oat Crown Rust Resistance Using Phenotypic Data from Three Assessment Methods E. W. Jackson,"— Presentation transcript:
Qualitative and Quantitative Characterization and Mapping of Oat Crown Rust Resistance Using Phenotypic Data from Three Assessment Methods E. W. Jackson, D. E. Obert, M. Menz, G. Hu, J. B. Avant, J. Chong, and J. M. Bonman USDA-ARS Small Grains and Potato Germplasm Research Unit Aberdeen, ID
Ogle x TAM O-301 recombinant inbred line (RIL) population 1. Single-gene a. Phenotype population based parental reactions (DLA and FDNA) b. Conversion into a phenotypic marker c. Analyze for linkage between phenotypic marker and genotypic markers (Mapmaker EXP/3.0) 2. QTL a. Phenotype population (DLA, FDNA) b. Analyze data for QTLs using a genetic linkage map and genotypic marker data (WinQTL Cartographer) C HARACTERIZATION AND MAPPING
D ISEASE ASSESSMENT Peterson et al., 1948 Lamari, 2002
100bp 300bp 200bp 100bp 300bp 200bp 100bp P. Coronata isolates Oat D ISEASE ASSESSMENT
y = -3.5 (0.1)x + 34.9 (0.7), R 2 =0.997 (0.0004) S O N S S SS S S S OO O NN N
Mean cycle threshold values (Ct) and standard deviations (SD) for the four standards used to estimate fungal DNA within plates for each test.
Severity of crown rust infection of parents Ogle and TAM O-301 measured using three different methods after inoculation with Puccinia coronata isolate CR185 in field and greenhouse experiments. 4.2 12.4 45.3 4.8 10.3 19.5 3.0 5.7 10.9 1.5 4.0 10.1
Goodness-of-fit of crown rust resistant and susceptible Ogle x TAM-O-301 F 6:8 RIL’s to a single gene model screened in the field (n = 4 reps) and greenhouse using three methods of assessment.
Mean map positions to RFLP probe RZ543 of a candidate crown rust resistance gene in ‘Ogle’ based on three different assessments of Ogle x TAM-O-301 F 6:8 RIL’s inoculated with Puccinia coronata isolate IA 189 in both field and greenhouse experiments (n = 4 reps).
C ONCLUSIONS I. Single-gene analysis 1.Major gene conferring resistance to P. coronata isolate CR185 (race NBFB) in Ogle, which mapped to OT6. Resistance on KO13 Bush and Wise, 1996 O’Donoughue et al, unpublished II. QTL analysis Major QTL on OT6 using all 3 assessments (Ogle) Minor QTL on OT32 using visual and q-PCR (TAM O-301) Minor QTL on OT2 using q-PCR (TAM O-301) Candidate QTL on OT11 using q-PCR (Ogle) III. Advantages of qPCR 1.Resolution Differences between Ogle and TAM O-301 2.Mapping precision Placement of the single gene Two-point linkage vs. QTL on OT6 3.Mapping resolution Higher LOD score on OT6 and tighter QTL intervals Two additional QTLs resolved on OT2 and OT11
A KNOWLEDGEMENTS Coauthors, Dr. Monica Menz, Dr. James Chong, Dr. Don Obert, Dr. Mike Bonman, and Mrs. Jana Avant Mrs. Kathy Satterfield, Mrs. Irene Shackelford, Mrs. Rebeca Caldera USDA-ARS NSG&PR NSGC Aberdeen, ID