Introgressing Mutants
Introgression Line Library BC1 BC1 Selection BC2 Selection BC3 Selection BC3S1 Selection Trends in Plant Sci 8: 330-334
Mutant Stocks Mutant x Bowman F1 x Bowman BC1 x Bowman BC2 x Bowman BCn x Bowman Selfing Identify Mutant
Bowman Mutant Origins 2011 by American Society of Plant Biologists Druka A et al. Plantphysiol 2011;155:617-627
Mutant Introgression Segments 2011 by American Society of Plant Biologists Druka A et al. Plantphysiol 2011;155:617-627
Backcrossing clean-up 2011 by American Society of Plant Biologists Druka A et al. Plantphysiol 2011;155:617-627
Identifying causal genes 2011 by American Society of Plant Biologists Druka A et al. Plantphysiol 2011;155:617-627
Investigating natural variation in barley to identify genes involved in adaptation Luke Ramsay
Variation within cultivated barley Genome wide association genetics Driven by development of SNP genotyping platform Brought different areas of research together Gene space sequence - step-change for barley genetics
Delineation of winter : spring division SNP discovery with RNA-Seq 9K iselect genotyping platform - Community uptake Detailed SNP genotyping cultivated barley germplasm Winter: Spring division 9K iselect - genetic linkage map Comparison genomic regions associated with difference
Genetic Divergence Genomic regions associated with Spring/Winter divergence 1.0 0.5 0.0 1H 2H 3H 4H 5H 6H 7H F ST is a measure of genetic differentiation. Peaks represent where one allele is present in the winter population and another allele is present in the spring population Jordi Comadran
Candidate gene discovery & verification 9K iselect - genetic linkage map synteny Candidate gene; barley homologue of Centroradialis Barley mutant collection - derived NILs genotyped Early heading Praematurum-c (mat-c) allelic series
Adaption to new environments - HvCEN 40 o C max 40 o C max 20 20 0-20 1 3 5 7 9 11 0 1 3 5 7 9 11 20 o C min 20 o C min 0-20 1 3 5 7 9 11 10 0 1 3 5 7 9 11 10 5 0 precip. 1 3 5 7 9 11 Scandinavia Fertile Crescent 15 10 5 0 precip. 1 3 5 7 9 11 Fixation of haplotype III in European Spring barley Post domestication selection of existing allelic form shift in flowering time
Markers in backcrosses Backcross Inbred Lines (BILs) for mapping Backcross conversions Marker assisted breeding in Australia Fixation of target genes e.g. TILLING Advanced Backcross QTL Examples in many crops now Single Recombinant Chromosome Substitution Libraries (RCSLs) Work on barley in UK and USA
Target Control Rate (%) 98 100 Marker1 Trait Flanking Markers Major Gene Chromosome 100 90 80 70 60 50 40 30 20 10 0 TCR = Probability that target is still present (1-θ) n 0 5 10 15 20 25 30 Marker Distance from Target BC1 BC2 BC3 BC5 BC10
Target Control Rate (%) 98 100 110 Marker1 Trait Marker2 Flanking Markers Major Gene Chromosome TCR = Probability that target is still present [(1-θ 1 )(1-θ 2 )/(1-θ)] n 100 90 80 70 60 50 40 30 20 10 0 0 5 10 15 20 25 30 Marker Distances from Target BC1 BC2 BC3 BC5 BC10
DH & Markers in backcrosses Donor x Recipient Year F 1 x Recipient 0.5 Produce Doubled Haploids from Selected Heterozygotes BC 1 MAS for Target 1 BC 1 DH MAS for Target 1.5 Selected Homozygotes Backcross Inbreds MAS for Recipient Background 2 Backcross Conversions 3
DISCOVERY PHASE Benefits of MAS in Backcross Conversions Recessive Backcross Selection Mult & Trial NL & RLT Dominant Backcross MAS Backcross 0 2 4 6 8 10 12 Time (Years)
Backcross Conversions Recipient Parent Donor Parent F1 BC1 BC2 BC3 BCn Selfing Doubled Haploids & Marker assisted Selection Backcross Inbred
% Donor Genome Percentage Donor Genome in Stripe Rust Resistance Introgression (AFLPs) 70 60 50 40 30 20 10 0 Susceptible Resistant Toojinda et al., TAG 96: 121-131
Basic Pyramiding Steps Servin et al., Genetics 168: 513-523
Pyramiding Incrementally r ij =recombination between gene i & gene j 99% probability 3 Pedigree steps 2 Fixation steps 5 generations total Servin et al., Genetics 168: 513-523
Pyramiding Concurrently - Distant Parameters same Make 1 cross between distant founders 2 Pedigree steps 2 Fixation steps 4 generations total Servin et al., Genetics 168: 513-523
Pyramiding Concurrently - Close Parameters same Make each cross between close founders 2 Pedigree steps 2 Fixation steps 4 generations total Servin et al., Genetics 168: 513-523
Pyramiding virus resistance - 1 Werner et al., Mol Breed 16: 45-55
Pyramiding virus resistances - 2 Werner et al., Mol Breed 16: 45-55
Pyramiding virus resistances - 3 Werner et al., Mol Breed 16: 45-55