MARKER ASSISTED SELECTION PLANT GENETICS RECITATION March 8 th 2012

Why marker assisted selection?

MARKER ASSISTED SELECTION Individuals carrying the trait of interest are selected based on a marker which is linked to the trait and not on the trait itself. Indirect selection. Useful when the trait is difficult to measure, and/or is evident only at late developmental stages.

WinterFacult.Spring Kompolti Nure OSU11 Strider Igri Dicktoo 88Ab536 Tremois Morex Harrington ZCCT-H HvSnf2 Triumph

Kurtford iBison 1H+4H+5H I I I K I K I I K

The barley stripe rust resistance story ~ 1987

BARLEY STRIPE RUST

BARLEY STRIPE RUST Caused by fungus Puccinia striiformis f. sp. hordei Common in Mexico and South America but usually not in Oregon. It first appeared in the US in 1991 When infection is severe, losses of 50% are common

BARLEY STRIPE RUST Resistant cultivars are available It is necessary to develop resistant cultivars adapted to different barley growing areas Resistance to the disease is a quantitative trait (non-Mendelian inheritance) Three Quantitative Trait Loci (QTL) for stripe rust resistance have been mapped and their effects validated. There are molecular markers located in the target regions of the three QTL

Race characterization of BSR isolates from Huancayo, Peru. 2007

Cali-sib x BowmanShyri x GalenaCI10587 x Galena BSR-45D1-72D3-6 HarringtonBaronesse Orca BCDDB BCD47BCD12D3-6/B23D3-6/B61 AJOBUOPS

iBISON and BISON iBISON BISON

OWB Chr. 4H ORO EBmac701 baal29j18 SSR markers used for MAS *

OWB Chr. 1H 2_0749 Unmapped in OWB

2_0749 Unmapped in OWB

Shyri x Galena 2_0749* 2_0749* Inferred position 2_0749* MWG837 BCD098 Act8 OWB Chrom. 1H

OWB Chrom. 5H Cali sib x Bowman

Flanking markers in each target region Three resistance genes in chromosome 1H, 4H and 5H

THE PROBLEM KURTFORD 6 –rowed hooded feed barley Well adapted to California conditions Short height Stripe Rust Susceptible

iBISON 1H+4H+5H Resistance alleles for the three genes 2–rowed awned barley; short height

I Bison 1H 4H 5H Kurtford 1H 4H 5H X F1 heterozygote at 3 BSR resistance loci X Kurtford 1H 4H 5H BC1F1 12.5% of plants expected to be heterozygote at 3 BSR resistance loci. Year 1 RR RR RR SS SS SS RS RS RS SS SS SS Segregation in each locus: ½ RS ½ SS SOLUTION: The Kurtford Conversion

We have 589 BC1F1 seeds and we expect to find around 74 target heterozygotes at the 3 BSR resistance loci.We need: -Confirm choice of markers -DNA extraction for 589 plants -Genotyping for the 3 BSR resistance regions -Selection of targeted genotypes Bmag399 EST4473 EST4535 Baal29j18. Bags 4e Bmag337 Bmag223 Bmag812 1H 4H 5H Summer – Fall 2007 MAS1

Kurtford iBison 1H+4H+5H I I I K I K I I K

1.Selection of heterozygotes (~74) 2.10 seeds per selected plant ~ 740 BC1F2 plants. 3.Grow out and genotype We expect 25% of the BC1F2 to be homozygous for AT LEAST the 4H region (~ 185). Of these: ~ 104 homozygote only for 4H ~ 35 homozygote for 4H and 1H ~ 35 homozygote for 4H and 5H ~ 11 homozygote for 1H, 4H and 5H 25/64 (~ 38%) of the resistant plants will be homozygous hooded Winter 2008 MAS2 BC1F2 plants segregating in each locus: ¼ RR ½ RS ¼ SS

Winter 2008/2009 – seed increase Summer 2009 – validate resistance ~ 70 homozygous hooded, BSR resistant plants Field test

Abundant, gene-based markers make MAS more effective and informative

What makes a trait quantitative and not qualitative? Successful MAS may precede gene characterization Phenotypic performance is the ultimate measure of agronomic worth

MAS - coming to a field near you