Validation and Marker Assisted Selection of Three QTL Conditioning ...

Validation and Marker AssistedSelection of Three QTLConditioning Fusarium HeadBlight Resistance in WheatJianli Chen, Carl. Griffey, , Jody Fanelli, , and Saghai MaroofVirginia Polytechnic Institute & State University

Outline• Introduction• Materials & Methods• Results• Discussions

Constraints that Greatly Limit theDevelopment of Resistant Varieties• Poorly adapted and partially resistantgermplasm• Multiple components of resistance• Laborious and lack of cost effectiveselection system• Confounding environmental effects

Breeding Constrains: resistancecomplexity• Type I: Resistance to initial infection• Type II: Resistance to spread ofinfection within a spike• Type III: decomposition or non-accumulation of mycotoxin• Schroeder & Christensen, 1963; Wang& Miller, 1988; Mesterhazy, , 1995)

Disease Screening is Laborious and Costly UsingConventional Methods

MAS for FHB Resistance• MAS may be an alternative selection system for FHBresistance.• Extensive efforts have been made previously to map QTL fortype II resistance; but little is known about the significanceand genetic control of other types of resistance.• Over 18 chromosome regions have been reported; but fewhave been validated.• Two QTL on 3BS and 5AS have large effect and are stable inseveral known resistance sources.• One QTL on 3AS has a large effect in durum wheat (Chen etal., 2006), and in Frontana ( Steiner et al., 2004) and inF201wheat (Shen(et al., 2003).• Little is known about the effectiveness of MAS of the threeQTL in adapted backgrounds.

Objectives of Current Study• Validate and characterize the three QTLs fortype I, type II, and type III resistance• Elucidate the potential use of MAS for thethree QTL in adapted backgrounds

Materials & Methods• Experiment I• 96 Doubled haploid lines derived froma cross between W14 and Pioneer2684• Two GH tests (2001 & 02) – floretinoculation• One field test (2004) – sprayinginoculation

Materials & Methods• Experiment II• Sixty SRW wheat lines• These lines were developed by acombination of top-crossing, backcrossing,and doubled haploid breeding methods• Two GH tests (severity) and two field tests(incidence, severity, and DON)

Floret Inoculation - Greenhouse

FHB Severity (%) – Type II resistanceAt 21 st day after inoculation

Measurement of DON contentShimadzu QP2010 GC/MS system

Spray-Inoculation: Field

FHB Incidence (%) – Type I resistanceFHB Severity (%) – Type I & II resistance

DON Content – Type III resistance

Data Analysis• Linkage analysis - Mapmaker 3.0a, Lander et al.,1987• QTL analysis – QTL Cartographer, Wang et al.,2004• Composite interval mapping (CIM)• A QTL was declared significant when LOD > 2.2• LOD (logarithm of odds) threshold wasdetermined by permutation• Regression Analysis (SPSS, p < 0.05)• Homogeneous analysis-Duncan test

Results & Discussions• Validation of the three QTL in thefirst population• Genetic characterization of the threeQTL in the two populations• Strategy for MAS of the three QTL

Marker Validation – 23 SSR + 2 STS3BSgwm389barc075gwm533barc133STS3B142STS3B66gwm493cfd079Liu et al., 2006;Chen et al., 20065ASbarc001barc117barc056barc186barc040barc100gwm156barc186barc197Hermann et al.,2004; Chen et al.,20063ASbarc045gwm002gwm032gwm674barc019barc067wmc428wmc264Shen et al., 2003;Somers, et al., 2005;Chen et al., 2006

Fig.1. Genetic Maps of W14

Fig. 2. Likelihood map for type I, II and IIIresistance QTL

Table 3. Putative QTL for type I, II, and IIIQTL-markersType IType IIType IIIQTLClosestmarkerLODR 2LODR 2LODR 23BSXgwm533A7.10.283BSXbarc1332.50.097.30.266.30.243BSXSTS1421.70.067.80.286.40.245ASXbarc1177.70.292.60.09

Table 4. Homogeneous analysis among fourhaplotypes of two QTL for type I, II, and IIIresistance in DH population.3BSHaplotypes5ASNo. ofGreenhouse,2001&02Mean DataField, 2004M1,M2M1LinesIIIIIII & II1++2414.5a2.8a43.9a10.9a2+-2217.1a3.9a65.9bc15.3bc34--+-151524.8b41.3c15.2a56.3c53.7ab78.2c14.2ab20.1cA to c represents homogeneous subsets conducted by Duncan test at p < 0.05.

Marker Validation – 23 SSR + 2 STS3BSgwm389barc075gwm533barc133STS3B142STS3B66gwm493cfd0795ASbarc001barc117barc056barc186barc040barc100gwm156barc186barc1973ASbarc045gwm002gwm032gwm674barc019barc067wmc428wmc264

Table 1. Comparison of Coefficients of Determination (R 2 x100) of three QTL on three components of FHB resistance intwo populations (A and B)QTLFHB FieldIncidence (%)FHB FieldSeverity (%)FHB DONContent(ppm)FHBGreenhouseSeverity (%)ABABABAB3BS10.023.817.426.826.5-40.55.05AS31.621.016.514.48.5--5.53AS-29.2-18.5---4.9Allmarkers42.952.233.542.436.3-43.510.93BS: Barc133, STS3B-142; 5AS: Barc117, Barc186; 3AS: Wmc428, WMC264

MAS of Three Components of FHB Resistance– Experiment IIType IType I & IIType IIIType IIQTLNo. ofLinesFieldIncidence (%)FieldSeverity (%)FieldDON (ppm)GreenhouseSeverity (%)3BS+3AS+5AS1146 a14.8 a1.0 a9.1 a3BS764 b21.0 b1.1 ab13.1 ab5AS864 b23.6 bc1.2 ab14.9 b3AS547 a19.9 b1.1 ab19.6 cnone2978 c27.6 c1.7 b13.7 b

Elite Lines with One to Three QTL in VTWheat Breeding ProgramQTLLines3BS+3AS+5AS3BS +5AS3AS + 3BS3BS5AS3ASnoneVA04W-389, VA04W-628, VA04W-631VA04W-433VA02W-555, Massey, VA01W-476VA04W-563, VA04W-592VA04W-474, VA00W-38VA04W-515VA02W-713, VA04W-439

Summary Remarks• This study targeted three main componentsof FHB resistance through validation andMAS of three major QTL on 3BS, 5AS, and3AS chromosome regions.• The 3BS QTL is a major one having largereffect than the 5AS and 3AS QTL for type I,II, and III (DON) resistance.• Pyramiding of 3BS with 5AS and 3ASwould improve overall FHB resistance.

Remarks cont.,• Ideal haplotype of the three QTL is comprisedof six favorable marker alleles, two on 3BS(barc133 & STS142), two on 5AS (barc117 &barc186), and two on 3AS (wmc428 &wmc264).• Elite lines having desirable marker haplotypewill provide breeding programs with a sourceof unique and adapted FHB resistant parentsand some of the lines also may have potentialfor release as cultivars.

Ongoing Research ApplicationsMarker-assisted assisted breeding for improved FHBresistance in VT wheat breeding program• Parental profiling of multiple FHB resistanceQTL in addition to 3AS, 3BS, and 5AS• Early generation selection of multiple QTL• Haplotyping of various QTL in advanced lines

ACKNOWLEDGEMENTS• U.S. Wheat and Barley Scab Initiative• Virginia Small Grain Association