ÿWPC3 `dJ¬ù¥ Ý5ñœÁM/0Eb&˜³`@.äõ¤úrú¹•u±ñ¢§Óƒs¿ —ûh‡Ïo®j¾¬Q›]§^<'=Ûù> ÓÚãf•ÐÒn1,€0.1)€andÏ8€segregated€for€SCN€resistance.€This€is€a€significant€deviationÏ(P<€0.001)€from€the€11.4€resistant€lines,€79.8€sensitive€lines€€andÏ18.8€segregating€lines€expected€in€Fòò5óó€derived€RILs€from€the€threeÏadditive€gene€model€for€SCN€race€3€resistance€(Rao„Arelli€andÏAnand,€1988,€Concibido€et€al.,€1994,€Webb€et€al.,€1995).ÌÌò òFrequency€Distribution€Of€SDS€Disease€Incidence.ó óòòóóÌ€€€€€€€€€For€the€SDS€susceptible€class€mean€DI€òòóóòòóóshowed€anÏapproximately€normal€(òòPóó€=€0.1),€continuous€distribution.€However,Ïthere€was€evidence€for€a€peak€below€40%€DI€and€a€significantÏkurtosis€(„0.83)€reflecting€a€flattened€distribution€(Fig.€1).Ì€€€€€€€€€For€the€SDS€resistant€class€mean€DI€òòóóòòóówas€not€a€normal€(òòPóó€=Ï0.01)€continuous€distribution.€There€was€evidence€for€a€bimodalÏdistribution,€a€significant€kurtosis€(„1.47)€reflecting€a€peakedÏdistribution€(Fig.€1).€This€might€reflect€the€action€of€one€majorÏgene€for€resistance€to€SDS€in€addition€to€those€associated€with€SCNÏresistance€within€this€class.Ì€€€€€€€€Of€the€36€lines€with€a€mean€DI€higher€than€Essex€(Fig.€1)Ïonly€2€were€SCN€race€3€resistant.€Among€the€16€significantly€(òòPóó€<Ï0.05)€susceptible€transgressive€segregants€(Hnetkovsky€et€al.,Ï1996)€none€were€SCN€race€3€resistant.Ì€€€€€€€Among€the€eight€lines€with€a€mean€SDS€DI€significantly€(òòPóó€<Ï0.05)€lower€than€Forrest€(Hnetkovsky€et€al.,€1996),€only€one€was€SCN€race€3€susceptible.€These€eight€transgressive€lines€may€beÏuseful€starting€points€for€developing€soybean€cultivars€withÏstronger€SDS€resistance.ÌÌò òFrequency€Distribution€Of€SCN€Index.ó óòòóóÌ€€€€€€€€€Using€untransformed€data,€the€mean€CI€òòóóòòóóshowed€an€abnormalÏ(W€=€0.88,€òòPóó€=€0.0001)€bimodal,€non„continuous€distribution€withÏsignificant€kurtosis€(„1.25,€òòPóó€<€0.01).€Square€root€transformationÏof€the€CI€data€failed€to€normalize€the€data€(W€=€0.85,€òòPóó€=€0.0001),Ïwith€significant€kurtosis€(„1.10)€and€significant€skewness€(„0.51,ÏòòPóó€<€0.01).Ì€€€€€€€For€the€SCN€susceptible€class€mean€CI€òòóóòòóóshowed€an€abnormal€(òòPóóÏ=€0.0008)€distribution€for€both€untransformed€and€square€rootÏtransformed€data.€There€was€evidence€for€significant€kurtosis€(„¼0.87)€in€untransformed€data€reflecting€a€flattened€distribution€andÏsignificant€skewness€(„0.49)€in€transformed€data€(Fig.€1).ÏTherfore,€the€bimodal€distribution€was€not€simple.Ì€€€€€€€€€For€the€SDS€resistant€class€mean€CI€òòóóòòóówas€not€a€normal€(òòPóó€=Ï0.0008)€continuous€distribution.€There€was€evidence€for€bothÏsignificant€kurtosis€(„0.85)€reflecting€a€peaked€distribution€andÏskewness€(0.70)€(Fig.€1).ÌÌò òDNA€Markers€Associated€With€Disease€Incidence.Ì€€€€€ó óTo€detect€loci€conditioning€partial€resistance€to€SDS,€weÏtested€associations€between€Fòò5:9óó€genotypic€classes€for€each€DNAÏmarker€and€the€corresponding€mean€SDS€DI€across€five€locations€over€four€years.€€Four€chromosomal€regions€had€significant€(òòPóó€<€0.005)Ïeffects€on€DI€(Table€2,€Fig.€2).€The€two€regions€identified€onÏlinkage€groups€C€and€N€were€reported€previously€(Hnetkovsky€et€al.,Ï1996)€and€did€not€greatly€change€significance€by€the€analysis€ofÏtransformed€data€or€additional€flanking€markers,€therefore€they€areÏnot€described€in€further€detail.€The€position€of€SDS€resistanceÏloci€within€each€region€relative€to€the€DNA€markers€was€determinedÏby€QTL€analysis€(Paterson€et€al.,€1988)€using€linked€DNA€markersÏ(Fig.2).€Ì€€€€€€The€locus€identified€by€RAPD€marker€OG13òò490óó,€accounted€for€17%Ïof€total€variation,€with€òòPóó€=€0.0001€(Table€2).€This€RAPD€markerÏmapped€within€18€cM€of€RFLP€marker€A117H€(òòHindóóIII€bands,€Essex€=Ï2.4€kbp€and€Forrest€=€2.2€kbp)€so€the€QTL€was€tentatively€assignedÏto€linkage€group€A€of€the€soybean€RFLP€map€(Shoemaker€and€Olson,Ï1993).€However,€the€polymorphic€bands€were€not€generated€with€theÏsame€restriction€enzyme€as€the€locus€A117D„1€that€mapped€to€theÏsoybean€linkage€group€A,€locus€1€(Shoemaker€and€Olson,€1993;ÏShoemaker€and€Specht€1995)€and€this€RFLP€marker€can€also€map€toÏlinkage€group€B1€or€be€unlinked€(R.€Shoemaker,€personalÏcommunication,€Iowa€State€University).€The€A117H€marker€was€alsoÏstrongly€associated€with€DI€(òòRòòóó2óó€=€0.31,€òòPóó€=€0.005).€However,€sinceÏthis€òòRòòóó2óó€was€based€on€selected€genotypes€(n€=€30)€it€is€anÏoverestimate€(Darvasi€and€Soller,€1991).€The€chromosomal€region€wasÏflanked€by€a€distal€RAPD€marker,€OI03òò450óó€9.5€cM€from€OG13òò490óó,€whichÏwas€also€significantly€associated€with€SDS€response€(òòRòòóó2óó€=€0.20,€òòPóóÏ=€0.0001)€(Fig.€2).Ì€€€€€€Another€locus,€identified€by€RAPD€marker€OE04òò450óó,€accounted€forÏ32%€of€the€total€variation€in€DI,€with€òòPóó€=€0.0011€(Table€2).€TheÏRAPD€marker€mapped€within€11€cM€of€the€RFLP€marker€A112I€(òòEcoóóRIÏbands,€Essex€=€5.0€Kbp,€Forrest€=€8.0€kbp).€The€Essex€band€wasÏpolymorphic€with€the€same€restriction€enzyme€and€was€of€similarÏsize€as€the€òòG.maxóó€allele€of€A121I„1€that€mapped€to€the€soybeanÏlinkage€group€G,€locus€1€(Shoemaker€and€Olson,€1993;€Shoemaker€andÏSpecht,€1995).€Therefore,€the€QTL€was€tentatively€assigned€toÏlinkage€group€G€of€the€soybean€RFLP€map€(Shoemaker€and€Olson,Ï1993).€òòóóThe€RFLP€marker€was€not€significantly€associated€with€DI€(òòRòòóó2óóÏ=€0.05,€òòPóó€=€0.06).€OE04òò450óó€òòóówas€linked€(15.7€cM)€to€RAPD€marker,ÏOE02òò1000óóòòóó€(Fig.€2)€which€òòóówas€also€associated€with€DI€(òòRòòóó2óó€=€0.19,€òòPóó€=Ï0.0097).Ì€€€€€€òòóóThe€Mapmaker/QTL€data€suggest€that€both€QTL€were€detectableÏover€large€chromosomal€regions.€The€preliminary€evidence€of€two€LODÏpeaks€in€both€linkage€groups€G€and€N€may€reflect€the€action€ofÏclustered€QTL,€sampling€bias€or€scoring€errors.€MultidimensionalÏANOVA€showed€no€significant€interactions€between€the€QTL€(òòPóó€>Ï0.05),€therefore€the€QTL€are€expected€to€be€additive.€Ì€€€€€€€€€Jointly,€the€four€chromosomal€regions€explain€about€70%€ofÏthe€total€variation€in€DI.€The€heritability€of€SDS€DI€in€Essex€xÏForrest€has€been€estimated€at€90%€on€a€line€mean€basis€withÏtransformed€data€(Table€1)€so€that€more€chromosomal€regionsÏaffecting€SDS€resistance€may€yet€be€detected€in€this€progenyÏpopulation.€An€analysis€with€110€molecular€markers,€which€encompassÏabout€2,057€cM€(about€67%€of€the€genome)€is€unlikely€to€detect€all€SDS€resistance€genes€segregating€in€the€progeny€population.€InÏaddition,€100€plant€lines€is€a€relatively€small€sample€to€detectÏall€genes€controlling€SDS€disease€response.€Further,€only€thoseÏpartial€resistance€loci€with€relatively€large€effects€and€closelyÏlinked€to€markers€would€be€expected€to€be€detected€(Landers€andÏBotstein,€1989).Ì€€€€€€€As€judged€by€one€way€ANOVA€and€Mapmaker/QTL€the€QTL€areÏapproximately€equal€in€their€effect€on€SDS€response.€€The€allelesÏat€the€four€mapped€QTL€with€beneficial€effects€on€DI€were€derivedÏfrom€Essex€€at€one€locus€(linkage€group€C)€and€Forrest€at€the€otherÏthree€loci€(linkage€group€A,€G€and€N).€Therefore,€favorable€allelesÏfor€partial€resistance€to€fungal€pathogens€derived€from€theÏsusceptible€parent€do€contribute€a€portion€of€partial€resistanceÏ(Bubeck€et€al.,€1992;€Wang€et€al.,€1994;€Young€et€al.,€1994,ÏHnetkovsky€et€al.€1995).Ì€€€€€€€From€mapping€of€these€four€QTL€with€molecular€markers,€weÏhave€addressed€each€of€the€four€statistical€assumptions€concerningÏthe€QTL€(Wright€et€al.,€1968)€inherent€in€the€inheritance€studiesÏof€SDS€response€(Matthews€et€al.,€1991;€Gibson€et€al.,€1994).€TheÏinteractions€among€the€four€independent€QTL€were€additive,€no€clearÏevidence€for€QTL€clustering€was€apparent,€the€QTL€were€about€equalÏin€effect€but€coordinate€action€among€parental€QTL€was€notÏabsolute.€Ìò òÌAssociations€Between€Locationsó óÌ€€€€€SDS€infestation€in€the€five€locations€was€consistent€and€severe€except€in€C91€where€infestation€was€moderate€(Hnetkovsky€etÏal.,€1996).€The€locus€on€linkage€group€A,€identified€by€OG13òò490óó€andÏOI03òò450óó,€was€associated€with€DI€(òòPóó€<€0.005,€òòRóóòò2óó€=€0.10„0.24òòóó)€in€fourÏof€the€five€locations€tested€(Table€3).€In€the€fifth€location,€P91,ÏOG13òò490óó€was€weakly€associated€with€DI€(òòPóó€=€0.0069,€òòRóóòò2óó€=€0.08).€TheÏlocus€on€linkage€group€G,€identified€by€OE04òò450óó€(and€less€stronglyÏby€OE02òò1000óó),€was€associated€with€DI€(òòPóó€<€0.005,€òòRóóòò2óó€=€0.1„0.3)€in€fourÏof€the€five€locations€tested€(Table€3).€In€the€fifth€location,€C92,Ïonly€OE04òò450óó€was€weakly€associated€with€DI€(òòPóó€=€0.0052).€Using€òòóótheseÏfour€markers€in€Mapmaker/QTL,€the€presence€and€location€of€both€QTLÏwere€stable€in€all€locations€tested€and€could€explain€8„30€%€of€theÏvariability€in€DI€per€location.Ì€€€€€€€As€noted€previously€for€SDS€QTL€(Hnetkovsky€et€al.,€1996),Ïthe€resistance€to€SDS€conferred€by€the€chromosomal€regions€wasÏenvironmentally€stable.€Therefore,€these€markers€will€be€useful€forÏselecting€stable€SDS€resistant€genotypes€throughout€the€SDSÏinfested€soybean€production€area.€The€environmental€stability€ofÏall€four€SDS€resistance€QTL€contrasts€with€many€loci€conferringÏpartial€resistance€to€fungal€pathogens€of€corn€and€rice€(Bubeck€etÏal.,€1992;€Wang€et€al.,€1994).€Ìò òó óÌò òDNA€Markers€Associated€With€Disease€Severityó ó€Ì€€€€€€The€locus€identified€by€RAPD€marker€OG13òò490óó,€accounted€for€10%Ïof€total€variation€in€DS,€with€òòPóó€=€0.0013€(Table€4).€The€linkedÏRFLP€marker€A117H€was€weakly€associated€with€DS€(òòRòòóó2óó€=€0.12,€òòPóó€=Ï0.09)€based€on€selective€genotyping€(n€=€30).€The€linked€RAPD€marker,€OI03òò450óó€òòóówas€significantly€associated€with€DS€(òòRòòóó2óó€=€0.12,€òòPóó€=Ï0.001)€(Table€4).Ì€€€€€€Another€locus,€identified€by€RAPD€marker€OE04òò450óó,€accounted€forÏ39%€of€the€total€variation€in€DS,€with€òòPóó€=€0.0002€(Table€4).€€òòóóTheÏlinked€RFLP€marker€A112I€was€not€significantly€associated€with€DSÏ(òòRòòóó2óó€=€0.06,€òòPóó€=€0.06).€The€linked€RAPD€marker€OE02òò1000óóòòóó€(Fig.€2)€òòóówasÏassociated€with€DS€(òòRòòóó2óó€=€0.19,€òòPóó€=€0.0097).Ì€€€€€€òòóóThe€MAPMAKER/QTL€data€suggest€that€together,€the€twoÏchromosomal€regions,€may€explain€37.3%€of€the€total€variation€inÏDS.€Multidimensional€ANOVA€showed€that€in€combination€with€the€twoÏQTL€previously€reported€on€linkage€groups€C€and€N€(Hnetkovsky€etÏal.,€1996)€the€4€QTL€jointly€explain€about€50%€of€the€variabilityÏin€DS.€The€heritability€of€SDS€DS€in€Essex€x€Forrest€has€beenÏestimated€at€78%€(Table€1)€on€a€line€mean€basis€so€that,€as€for€DI,Ïmore€chromosomal€regions€affecting€SDS€resistance€may€be€discoveredÏin€this€progeny€population.€None€of€the€110€markers€testedÏidentified€loci€strongly€associated€with€DS€that€were€notÏassociated€with€DI.€Therefore,€DI€was€a€useful€indicator€of€theÏeffects€of€all€loci€tested€on€DS.Ìò òó óò òDNA€Markers€Associated€with€Yield.ó óÌ€€€€€In€ANOVA,€the€chromosomal€region€identified€by€OG13òò490óó€onÏlinkage€group€A€was€also€significantly€associated€with€mean€yieldÏin€SDS€infested€test€sites,€accounting€for€9€%€of€variation€(òòPóó€=Ï0.0037,€Table€5).€The€association€was€also€significant€(òòPóó€<€0.005,òòÏRóó€=€0.08„0.12)€in€two€of€five€locations,€C92€and€R93.€The€linkedÏmarker€OI03òò450óó€was€significantly€associated€with€mean€yield€in€SDS€infested€test€sites,€accounting€for€12%€of€variation€(òòPóó€=€0.0012).ÏThe€association€was€again€significant€(òòPóó€<€0.005,€òòRóóòò2óó€=€0.09„0.17)Ïin€two€of€five€locations,€P91€and€C92€but€not€R93.€As€measured€byÏMapmaker€the€presence€and€location€of€the€QTL€was€stable€in€P91,ÏC92€and€R93€and€could€explain€5„20€%€of€the€variability€in€yieldÏper€location.€Therefore,€these€markers€together€are€associated€withÏyield€in€three€locations.€This€chromosomal€region€may€conditionÏboth€SDS€DI€and€yield,€with€yield€a€consequence€of€variation€in€DIÏin€SDS€pathogen€infested€fields.€Ì€€€€€€€€The€chromosomal€region€identified€by€OE04òò450óó€on€linkage€groupÏG€was€not€significantly€associated€with€mean€yield€(òòPóó€=€0.028,€òòRóóòò2óóÏ=€0.16)€but€was€associated€with€yield€in€R93€(òòPóó€=€0.0006,€òòRóóòò2óó€=Ï0.35).€The€linked€marker€OE02òò1000óó€was€also€not€significantlyÏassociated€with€mean€yield€in€SDS€infested€test€sites€(òòPóó€=€0.061,ÏòòR€óó=€0.11).€However,€the€association€was€significant€(òòPóó€<€0.009,€òòRóóòò2óóÏ=€0.2„0.32)€in€two€of€five€locations,€R93€and€C92.€Therefore,Ïtogether€these€markers€were€associated€with€yield€in€two€locations.ÏThis€chromosomal€region€may€condition€both€SDS€DI€and€yield,€as€aÏresult€of€variation€in€DI,€in€SDS€infested€fields.€As€measured€byÏMapmaker€the€presence€and€location€of€the€QTL€were€stable€in€C92Ïand€R93€and€could€explain€14„32€%€of€the€variability€in€yield.Ì€€€€€€Jointly€with€the€chromosomal€region€on€linkage€group€NÏ(Hnetkovsky€et€al.,€1996),€the€three€QTL€explain€about€35%€ofÏvariation€in€mean€yield€in€multidimensional€ANOVA.€The€heritabilityÏof€yield€in€SDS€infested€locations€in€Essex€x€Forrest€has€beenÏestimated€at€83%€(Table€1)€on€a€line€mean€basis€so€that€additional€chromosomal€regions€affecting€yield€in€SDS€infested€fields€remainÏto€be€discovered€in€this€progeny€population.Ì€€€€€€€Considering€single€locations,€the€three€QTL€on€linkageÏgroups€A,€G€(this€study)€and€N€(Hnetkovsky€et€al.,€1996)€were€allÏstrongly€associated€with€yield€(òòPóó€<€0.005)€in€two€environments,€ÏC92€and€R93€whereas€only€the€QTL€on€linkage€group€N€was€associatedÏin€V90€and€only€the€QTL€on€linkage€group€A€was€associated€in€P91.ÏHowever,€in€all€the€non„significant€environments,€the€trend€isÏtoward€yield€benefit€associated€with€the€Forrest€allele€for€theÏthree€QTL.€The€association€between€these€QTL€and€the€DI€trait€didÏnot€show€the€environmental€sensitivity€observed€for€the€yield€traitÏ(Table€4).€In€addition,€significant€but€only€moderate€correlationÏcoefficients€(òòróó€<€0.6)€between€yield€and€DI€or€DS€have€beenÏreported€(Gibson€et€al.,€1994).€Therefore,€factors€in€addition€toÏSDS€DI€may€alter€yield€significantly€in€some€environments€(GibsonÏet€al.,€1994).€The€underlying€QTL€conditioning€these€factors€haveÏnot€yet€been€detected€(òòPóó€<€0.02)€in€Essex€by€Forrest.€However,Ïmajor€QTL€conditioning€yield,€independent€of€SDS€response€have€beenÏreported€in€soybean€(Mansur€et€al.,€1993b).Ìò òÌDNA€Markers€Associated€With€Cyst€Nematode€race€3€responseó ó.€Ì€€€€€€Associations€between€markers€and€CI€were€made€with€bothÏtransformed€and€untransformed€data€in€both€ANOVA€and€Mapmaker€QTL.ÏSince€the€nature€of€the€associations€did€not€change€substantially,Ïthe€results€with€untransformed€data€are€presented.Ì€€€€€€The€locus€identified€by€RAPD€marker€OI03òò450óó€òòóóaccounted€for€14%€of€total€variation€in€SCN€index,€with€òòPóó€=€0.0001€(Table€6).ÏòòòòóóóóHowever,€the€linked€RAPD€marker,€OG13òò490óó€€òòóówas€not€significantlyÏassociated€with€SCN€index€(òòRòòóó2óó€=€0.14,€òòPóó€=€0.056).€The€beneficialÏallele€for€SCN€race€3€resistance€was€derived€from€Forrest,€the€SCNÏrace€3€resistant€parent.€Multidimensional€ANOVA€with€all€four€QTLÏjointly€explained€just€14€%€of€CI€variability€and€showed€that€noÏsignificant€interactions€occurred.Ì€€€€€€òòóóThe€MAPMAKER/QTL€data€suggest€that€the€chromosomal€region€mayÏexplain€about€13€%€of€the€total€variation€in€SCN€index.€€TheÏheritability€of€SCN€index€in€Essex€x€Forrest€has€been€estimated€atÏ95%€on€a€line€mean€basis€so€that€additional€chromosomal€regionsÏaffecting€SCN€race€3€resistance€remain€to€be€discovered€in€thisÏprogeny€population.€Those€loci€strongly€associated€with€SCN€race€3Ïresistance€in€other€reports€(Concibido€et€al.,€1994;€Webb€et€al.,Ï1995)€have€not€be€categorically€identified€or€excluded€in€the€ExFÏpopulation.€Further€map€integration€by€scoring€additional€RFLPÏmarkers€(Shoemaker€and€Specht,€1994),€sequence€characterizedÏamplified€regions€(Witsenboer,€1995)€and€micro„satellite€markersÏ(Akkaya€et€al.,€1995)€is€needed.Ì€€€€€€That€one€region€containing€an€SCN€race€3€resistance€QTL€wasÏstrongly€associated€with€SDS€resistance€may€partly€explain€theÏassociation€between€SDS€resistance€and€SCN€resistance€inÏinheritance€studies€(Matthews€et€al.,€1991;€Njiti€et€al.,€1996)€andÏvariety€trials€(Rupe€et€al.,€1989;€Gibson€et€al.,€1994).€The€locusÏnear€OI03òò450óó€explains€only€20€%€of€SDS€response€or€one€third€of€theÏvariability€for€SDS€currently€explained€by€QTL,€this€is€much€less€than€the€50%€of€phenotypic€variability€for€SDS€response€explainedÏby€SCN€resistance€in€Essex€by€Forrest€(Matthews€et€al.,€1991;ÏGibson€et€al.,€1994)€therefore€additional€QTL€associated€withÏresistance€to€both€diseases€may€remain€to€be€discovered.Ì€€€€€€€We€cannot€distinguish€between€close€linkage€of€the€SDS€andÏSCN€QTL€and€pleiotropy€of€a€single€QTL€by€this€analysis.€FineÏmapping€and€QTL€introgression€will€be€employed€to€distinguish€theseÏtwo€hypotheses.€Certainly,€cross€protection€by€a€single€geneÏproduct€to€pathogens€from€two€separate€kingdoms€is€not€withoutÏprecedent€(Ward€et€al.,€1991).Ìò òÌImplications€for€Genetic€Dissection€and€Marker€Assisted€Breedingó ó€€Ï€€€€€The€breeding€application€for€which€this€analysis€was€initiatedÏis€the€use€of€QTL€information€for€marker€assisted€selection.€TheÏmarkers€A117H,€OG13òò490óó,€OI03òò450óó,€OE02òò1000óó,€OE04òò450óó,€K455D„1,€OO05òò250óó,€OC01òò650óóÏand€OF04òò1600óó€can€be€used€for€marker€assisted€selection€of€the€fourÏQTL€for€partial€SDS€resistance.€Their€effectiveness€as€selectionÏtools€depends€on€the€marked€QTL€controlling€SDS€response€being€bothÏadditive€and€stable€during€inter„crossing€or€back„crossing.Ì€€€€€€€Table€7€shows€that€the€beneficial€alleles€of€theÏindependently€identified€QTL€are€frequent€among€the€eight€linesÏwhich€are€more€resistant€to€SDS€than€Forrest€(Hnetkovsky€et€al.Ï1995).€Only€one€line,€ExF47,€seems€to€lack€one€of€the€QTL€forÏresistance€(linkage€group€G)€as€judged€by€both€flanking€markers,Ïtherefore,€both€the€genotypic€and€phenotypic€rank€largelyÏcorrespond.€Relatively€few€of€these€lines€are€recombinant€within€the€interval€containing€any€of€the€four€QTL.€The€line€ExF78€appearsÏto€be€ð ðthe€exception€that€probes€the€ruleðð€(Gould,€1980),€it€isÏclearly€recombinant€with€the€regions€containing€all€four€QTL.€It€isÏnot€coincidental€that€this€line€shows€the€lowest€DI€by€aÏsignificant€margin,€as€well€as€the€third€highest€yield€of€all€linesÏin€the€population.€Beneficial€effects€of€recombination€within€theÏregions€containing€QTL€implies€that€one€or€more€of€the€identifiedÏchromosomal€regions€may€carry€clustered€QTL€of€opposite€effect€onÏSDS€response.€We€expect€clustered€QTL€may€exist€on€linkage€group€AÏsince€the€Lod€curve€for€DI,€DS€and€yield€is€bimodal€(Tables€2,€4Ïand€5)€and€linked€markers€show€different€stability€of€associationsÏin€single€environments€(Table€3€and€5).€However,€sampling€errors€orÏscoring€errors€may€explain€this€phenomenon.€Ì€€€€€The€detection€of€epistatic€interactions€between€unlinked€lociÏis€one€method€to€separate€clustered€QTL€within€an€interval€withoutÏanalysis€of€additional€populations€(Lark€et€al.,€1995).€Analyses€ofÏinteractions€among€the€markers€linked€each€of€the€four€QTL€byÏmultidimensional€ANOVA€was€not€significant€(P>€0.05)€and€does€notÏsupport€QTL€clustering.€However,€the€94€unlinked,€non„traitÏassociated€loci€remain€to€be€tested€in€this€fashion.€However,€theÏmultidimensional€ANOVA€did€confirm€that€the€four€SDS€resistance€QTLÏwere€additive€and€not€epistatic.€Ì€€€€€€The€possibility€that€the€line€ExF78€represents€an€eliteÏsource€of€germplasm€capable€of€contributing€SDS€resistance€coupledÏwith€high€yield€potential€will€be€explored€by€both€back„crossingÏand€inter„crossing€followed€by€marker€assisted€selection.€Comparison€of€the€performance€of€the€derived€progeny€populationsÏfrom€both€this€line€and€others,€such€as€ExF59,€will€test€theÏstability€and€additive€nature€of€the€marked€QTL€in€other€geneticÏbackgrounds.€The€possibility€of€clustered€QTL€will€€be€investigatedÏby€this€approach€as€well€as€by€genetic€dissection€in€sub„lineÏpopulations€(Hnetkovsky€et€al.,€1996).ÇÌò ò€€€€€€€€€€€€€€€€€€€€€€€€€ACKNOWLEDGEMENTSó óÌ€€€€We€thank€Dr.€R.€Shoemaker€for€the€RFLP€probes€and€some€parentÏRFLP€polymorphism€data.€We€thank€Dr.€P.€Keim€for€much€parent€RFLPÏpolymorphism€data.€We€thank€Dr.€D.€Webb€for€some€novel€parent€RFLPÏdata€and€verification€of€the€RFLP€polymorphism€data.€We€thank€allÏthe€workers€on€the€SDS€field€team€at€Southern€Illinois€UniversityÏat€Carbondale€from€1987€to€present.€Thanks€to€Dr.€V.€Njiti,€Dr.€O.ÏMyers€Jr.,€Dr.€R.€Prabhu€and€Dr.€V.€Concibido€for€critical€readingÏof€the€manuscript.€This€work€was€supported€in€part€by€grants€fromÏthe€Illinois€Soybean€Program€Operating€Board€Nos.€92„18„125„3,€93„¼19„132„3,€94„20„143„3€and€North€Central€Soybean€Program€OperatingÏBoard€Nos.€95„20„43?€and€95„???Ç€€€€€€€€€€€€€€€€€€€€€€€€€€€ò òREFERENCESÌó óAkkaya,€M.S.,€R.C.€Shoemaker,€J.E.€Specht,€A.A.€Bhagwat,€P.B.€¼à0..àCregan.€1995.€Integration€of€simple€sequence€repeat€DNAÏmarkers€into€a€soybean€linkage€map.€Crop€Sci.€35:1439„1445.ÌBackes,€G.,€A.€Graner,€B.€Foroughi„Wehr,€G.€Fishbeck,€G.€Wenzel,Ïà0..àand€A.€Jahoor.€1995.€Localization€of€quantitative€trait€lociÏ(QTL)€for€agronomic€important€characters€by€the€use€of€a€RFLPÏmap€in€barley€(òòHordeum€vulgaraeóó€L.).€Theor.€Appl.€Genet.Ï90:294„302.ÌBubeck,€D.M.,€M.M.€Goodman,€W.D.€Beavis€and€D.€Grant.€1993.€¼à0..àQuantitative€trait€loci€controlling€resistance€to€gray€leafÏspot€in€maize.€Crop€Sci.€33:838„847.ÌConcibido,€V.,€Boutin,€S.,€Denny€R.,€Hautea€R.,€Orf,€J.€Young,€¼à0..àN.D.€1994.€DNA€marker€analysis€of€loci€underlying€resistanceÏto€soybean€cyst€nematode€òò(Heterodera€glycineóó€Ichinohe).€CropÏSci.€34:240„246.ÌDarvasi,€A.€and€M.Soller.€1992.€Selective€genotyping€forÏà0..àdetermination€of€linkage€between€a€marker€locus€and€aÏquantitative€trait€locus.€Theor.€Appl.€Genet.€85:353„359.ÌGibson,€P.T.,€M.A.€Shenaut,€V.N.€Njiti,€R.J.€Suttner€and€O.€Myers,Ïà0..àJr.€1994.€Soybean€varietal€response€to€sudden€death€syndrome.Ïp.20„40.€€In€D.€Wilkinson€(ed.)€Proc.€Twenty„fourth€SoybeanÏSeed€Res.€Conf.,€Chicago,€IL€6„7€Dec.,€Am.€Seed€Trade€Assoc.,ÏWashington€DC.ÌGoldman,€I.L.,€Paran,€I.,€and€Zamir,€D.€1995.€Quantitative€trait€¼à0..àlocus€analysis€of€a€recombinant€inbred€line€population€derived€from€a€òòLycopersicon€esculentumóó€x€òòLycopersicon€cheesmaniióóÏcross.€Theor.€Appl.€Genet.€90:925„932.ÌGould,€S.J.€1980.€The€Panda's€Thumb.€Cambridge€University€Press.Ïà0..àCambridge,€UK.€pp42„62.ÌHartwig,€E.E.€and€J.M.€Epps.€1973.€Registration€of€ForrestÏà0..àsoybeans.€Crop€Sci.13:287.ÌHnetkovsky,€N.,€S.J.C.€Chang,€T.W.€Doubler,€P.T.€Gibson€and€D.A.Ïà0..àLightfootòòóó.€1996.€Genetic€Mapping€of€Loci€Underlying€FieldÏResistance€to€Soybean€Sudden€Death€Syndrome€(SDS).€Crop€SciÌ€€€€€€36(2):(in€press).ÌJansen,€R.C.,€J.W.€Van€Ooijen,€P.€Stam,€C.€Lister€and€C.€Dean.€¼à0..à1995.€Genotype„by„environment€interaction€in€genetic€mappingÏof€multiple€quantitative€trait€loci.€Theor.€Appl.€Genet.Ï91:33„37.ÌLander,€E.,€P.€Green,€J.€Abrahamson,€A.€Barlow,€M.€Daley,€S.€¼à0..àLincoln€and€L.€Newburg.€1987.€MAPMAKER:€An€interactiveÏcomputer€package€for€constructing€primary€genetic€linkage€mapsÏof€experimental€and€natural€populations.€Genomics€1:174„181.ÌLander,€E.€and€D.€Botstein.€1989.€Mapping€Mendelian€factors€¼à0..àunderlying€quantitative€traits€using€RFLP€linkage€maps.ÏGenetics€121:€185„199.ÌLark,€K.G.,€J.€Orf,€L.M.€Mansur.€1994.€Epistatic€expression€of€¼à0..àquantitative€trait€loci€(QTL)€in€soybean€[òòGlycine€maxóó€(L.)ÏMerr.]€determined€by€QTL€association€with€RFLP€alleles.€Theor.ÏAppl.€Genet.€88:486„489.ÌLark,€K.G.,€F.€Adler,€L.M.€Mansur€and€J.€Orf.€1995.€Interactions€à0..àbetween€quantitative€trait€loci€in€which€trait€variation€atÏone€locus€is€conditional€upon€a€specific€allele€at€another.ÏTheor.€Appl.€Genet.€88:486„489.ÌMansur,€L.M.,€A.L.€Carriquiry€and€A.P.€Rao„Arelli.€1993.€GenerationÏà0..àmean€analysis€of€resistance€to€race€3€of€soybean€cystÏnematode.€Crop€Sci.€33:1249„1259.ÌMansur,€L.M.,€Lark,€K.G.,€Kross,€H.€and€Oliviera€A.€1993b.€IntervalÏà0..àmapping€of€quantitative€trait€loci€for€reproductive,Ïmorphological€and€seed€traits€of€soybean€(Glycine€max€L.).ÏTheor€Appl.€Genet.€86:907„913.ÌMatthews,€W.J.,€V.N.€Njiti,€P.T.€Gibson€and€M.A.€Shenaut.€1991.€¼à0..àInheritance€of€soybean€SDS€response€in€segregating€Fòò5óó€and€Fòò6óóÏderived€lines.€Soybean€Genetics€Newsletter€18:102„108.ÌNjiti,€V.N.,€M.A.€Shenaut,€R.J.€Suttner,€M.E.€Schmidt€and€P.T.€¼à0..àGibson.€1995.€Segregation€pattern€for€soybean€sudden€deathÏsyndrome€(SDS)€response€in€Pyramid€x€Douglas€and€the€influenceÏof€soybean€cyst€nematode€(SCN)€resistance.€Crop€Sci.€SubmittedÏMarch,€1995.€ÌO'Donnell,€K.€and€L.E.€Gray.€1995.€Molecular€tools€for€theÏà0..àdetection€and€rapid€identification€of€the€soybean€sudden€deathÏsyndrome€pathogen,€òòFusarium€solanióó€f.€sp.€òòphaseolióó:ÏPhylogenetics€and€species€specific€PCR€primers.€Molec.€PlantÏMicr.€Inter..€In€press.ÌPaterson,€A.,€E.€Lander,€S.€Lincoln,€J.€Hewitt,€S.€Peterson€and€S.Ïà0..àTanksley.€1988.€Resolution€of€quantitative€traits€intoÏmendelian€factors€using€a€complete€RFLP€linkage€map.€Nature€335:721„726.ÌRao„Arelli€A.P.€and€S.C.€Anand.€1988.€Genetic€relationship€amongÏà0..àplant€introductions€for€resistance€to€race€3€of€soybean€cystÏnematode.€Crop€Sci.€28:650„652.ÌRoy,€K.W.,€G.W.€Lawrence,€H.H.€Hodges,€K.S.€McLean€and€J.F.€¼à0..àKillebrew.€1989.€Sudden€death€syndrome€of€soybean:€òòFusariumÏsolanióó€as€incitant€and€relation€of€òòHeterodera€glycinesóó€toÏdisease€severity.€Phytopath.€79:191„197.ÌRupe,€J.C.,€E.F.€Gbur€and€D.M.€Marx.€1991.€Cultivar€responses€toÏà0..àsudden€death€syndrome€of€soybean.€Plant€Dis.€75:47„50.ÌRupe,€J.C.€1989.€Frequency€and€pathogenicity€of€òòFusarium€solanióó€¼à0..àrecovered€from€soybeans€with€sudden€death€syndrome.€Plant€Dis.Ï73:581„584.ÌRupe,€J.C.€W.E.€Sabbe,€R.T.€Robbins€and€E.E.€Gbur.€1994.€Soil€andÏà0..àplant€factors€associated€with€sudden€death€syndrome€of€soybeanÏJ.Prod.€Agric.€6:218„221.ÌRupe,€J.C.€and€E.E.€Gbur.€1995.€Effect€of€plant€age,€maturity€groupÏà0..àand€environment€on€progress€of€sudden€death€syndrome€ofÏsoybean.€Plant€Dis.€75:47„50.ÌShoemaker,€R.C.€and€T.C.€Olson.€1993.€Molecular€linkage€map€of€¼à0..àsoybean€[òòGlycine€maxóó€L.€Merr.].€p€6.131„6.138.€In€S.J.€O'BrienÏ(ed.)€Genetic€Maps:€Locus€maps€of€complex€genomes.€Cold€SpringÏHarbor€Laboratory€Press,€New€York.ÌShoemaker,€R.C.€and€Specht,€J.E.€1995.€Integration€of€the€soybeanÏà0..àmolecular€and€classical€genetic€linkage€groups.€Crop€Sci.Ï35:436„446.ÌSmith,€T.J.€and€H.M.€Camper.€1973.€Registration€of€Essex€soybeans.Ïà0..àCrop€Sci.€13:495.€ÌStephens,€P.A.,€C.D.€Nickell€C.K.€Moots€and€S.M.€Lim.€1993.€¼à0..àRelationship€between€field€and€greenhouse€reaction€to€òòFusariumÏsolanióó€in€soybean.€Crop€Sci.€33:63„67.ÌThomas,€J.D.,€C.E.€Caviness,€R.D.€Riggs€and€E.E.€Hartwig.€1975.€¼à0..àInheritance€of€reaction€of€race€4€of€soybean€cyst€nematode.ÏCrop€Sci.€15:208„210.ÌWang,€G.L.€D.J.€Mackill€and€M.J.€Bonman.€1994.€RFLP€mapping€of€¼à0..àgenes€conferring€complete€and€partial€resistance€to€blast€inÏa€durably€resistant€rice€cultivar.€Genetics€136:1421„1430.ÌWard,€E.R.,€S.€Uknes,€S.C.€Williams,€S.S.€Dincher,€D.L.€Wiederhold,Ïà0..àD.C.€Alexander,€P.€Ahl„Goy,€J.€Metraux€and€J.A.€Ryals.€1991.ÏCo„ordinate€gene€activity€in€response€to€agents€that€induceÏsystemic€acquired€resistance.€Plant€Cell€3:1085„1094.ÌWebb,€D.M.,€B.M.€Baltazar,€A.P.€Rao„Arelli,€J.€Schupp,€P.€Keim,€¼à0..àK.€Clayton,€A.R.€Ferreira,€T.€Owens€and€W.D.€Beavis.€1995.€QTLÏaffecting€soybean€cyst„nematode€resistance.€Theor.€Appl.ÏGenet.€(in€press).ÌWilliams,€J.G.K.,€A.R.€Kubelik,€K.J.€Livak,€J.A.€Rafalski€and€S.V.Ïà0..àTingey.€1990.€DNA€polymorphism€amplified€by€arbitrary€primersÏare€useful€as€genetic€markers.€Nucl.€Acids€Res.€18:6531„6535.ÌWitsenboer,€H.,€R.V.€Kesseli,€M.G.€Fortin,€M.€Stanghellini,€R.W.Ïà0..àMichelmore.€1995.€Sources€and€genetic€structure€of€a€clusterÏof€genes€for€resistance€to€three€pathogens€of€lettuce.€Theor.ÏAppl.€Genet.€91:178„188.€ÌWright,€S.€1968.€Evolution€and€the€genetics€of€populations.€Vol.€1.Ïà0..àGenetics€and€Biometrical€foundations.€University€of€ChicagoÏPress,€Chicago,€USA.ÌYang,€X.B.€and€S.S.A.€Rizvi.€1994.€First€report€of€sudden€death€¼à0..àsyndrome€of€soybean€in€Iowa.€Plant€Dis.€78:830.ÌYoung,€N.D.,€D.€Manacio„Hautea,€N.S.€Danesh€and€L.€Kumar.€1994.€¼à0..àMapping€oligogenic€resistance€to€powdery€mildew€in€mungbeanÏwith€RFLPs.€Theor€Appl.€Genet.€87:243„249.ÌÇò òFIGURESó óÌÌFig.€1.€Frequency€distribution€of€the€mean€scores€across€five€fieldÏlocations€for€SDS€disease€incidence€among€100€recombinant€inbredÏlines€separated€by€SCN€response€class€from€a€cross€betweenÏcultivars€Essex€and€Forrest.€The€mean€DI€score€for€each€parent€inÏthe€same€environments€is€shown€in€Table€1.€The€least€significantÏdifference€between€parent€and€line€means€was€16.5€(òòPóó€<€0.05).ÌÌFig€2.€Locations€of€RFLP€markers,€RAPD€markers€and€two€QTLÏconditioning€SDS€DI.€The€QTL€were€putatively€assigned€to€linkageÏgroup€A€and€G€on€the€soybean€genetic€map€by€anchored€RFLPÏ(Shoemaker€and€Olson€1993).€END€indicates€the€likely€position€ofÏthe€telomere€on€that€linkage€group,€the€disjunct€bar€indicates€theÏrest€of€the€linkage€group.€Marker€names€are€given€on€the€left€andÏmarker„QTL€LOD€scores€are€given€on€the€right€of€each€linkage€group.ÏLOD€scores€at€markers€were€from€single„locus€analyses€of€additiveÏgene€effects€using€MAPMAKER/QTL€1.1.€Genetic€distances€(cM)€wereÏfrom€the€recombinant€inbred€line€function€of€MAPMAKER/EXP€3.0.€A€cMÏdistance€scale€is€shown€below€group€C.€The€estimated€position€ofÏthe€QTL€is€shown€based€on€2€cM€interval€mapping€using€MAPMAKER/QTLÏ1.1.€€Boxes€indicate€the€region€with€2„LOD€(100€fold)€likelihoodÏintervals.€ÇÓÓÔ€XXXÔÔO€6<þ6X9`("Courier 10cpiOÔTable€1.€Means€of€disease€incidence€(DI),€disease€severity€(DS),Ïyield€and€days€to€R6€of€100€Fòò5óó€derived€lines€from€the€cross€EssexÏby€Forrest€separated€by€SCN€resistance€class.Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ÌóóÌGen.ð'ð€€€n€€€€€DI€(%)€€€€DS€(1„9)€€€Yield€(kg€haòò„1óó)€€€Days€to€R6Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌEssex€€€€8€€€€58.9€€€€€€€1.6€€€€€€€€€3700€€€€€€€€€€€€104.9ÌForrest€€8€€€€16.5€€€€€€€1.2€€€€€€€€€3770€€€€€€€€€€€€112.1€Ì€€ÌSCN„R€€€24€€€€29.9€€€€€€€1.3€€€€€€€€€3820€€€€€€€€€€€€108.1ÌSCN„I€€€€8€€€€40.7€€€€€€€1.4€€€€€€€€€3550€€€€€€€€€€€€107.8ÌSCN„S€€€68€€€€56.0€€€€€€€1.6€€€€€€€€€3420€€€€€€€€€€€€108.1€€€ÌÌMean€€€€100€€€48.5€(23)€€1.5€(0.3)€€€3520€(360)€€€€€€108.1€(1.4)ÌÌh€(%)€€€100€€€90€€€€€€€€€78€€€€€€€€€€€€83€€€€€€€€€€€€€€€ND€€€€€€Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÏð'ð€V90,€Villa€Ridge€1990;€C91,€Cora€1991;€P91,€Pulaski€1991;€C92,€€Ï€€Cora€1992;€R93,€Ridgway€1993.Ìð(ð€Standard€deviation€among€progeny€line€means€in€each€location€andÏover€locations€is€shown€in€parentheses.€€€€ÇÔ€XXXÔÔO€6<þ6X9`("Courier 10cpiOÔÓ  ÓTable€2.€Intervals€showing€significant€associations€with€mean€SDSÏdisease€incidence€across€five€locations.Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ÏóóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Mean€DI€%€for€RILsÌ€€DNA€€€Linkage€€€€€€€€€€€€€€€€€€€€€€€€QTL€€€€€€with€alleles€fromÌMarker€€groupð'ð€€òòRóóòò2óó€€€€€òòPóó>F€€€€LODð(ð€€€€€var.ðð€€€€€Essex€€€€ForrestÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ÏóóÌòòóóòòóóòòóóòòóóOG13òò490óóà` ..` àA€€€0.17€€€€0.0001€€4.0€€€€€€17.0€€€€57.8òò+óó3.2€€38.5òò+óó2.9ÌOI03òò450óóà` ..` àA€€€0.20€€€€0.0001€€5.1€€€€€€20.0€€€€60.2òò+óó3.2€€39.6òò+óó3.1ÌÌOO05òò250óóà` ..` àC€€€0.13€€€€0.004€€€2.3€€€€€€11.1€€€€27.3òò+óó7.0€€61.0òò+óó6.1ÌòòóóK455D„1à` ..` àC€€€0.16€€€€0.0005€€2.9€€€€€€15.4€€€€40.4òò+óó4.4€€61.3òò+óó3.4ÏÌOE04òò450óóà` ..` àG€€€0.32€€€€0.0011€€3.4€€€€€€20.6€€€€65.3òò+óó7.9€€28.4òò+óó6.4ÌòòóóOE02òò1000óóà` ..` àG€€€0.19€€€€0.0097€€3.6€€€€€€23.8€€€€54.2òò+óó7.2€€31.6òò+óó4.6€ÏòòóóòòóóÌOC01òò570óóà` ..` àN€€€0.30€€€€0.001€€€1.8€€€€€€10.7€€€€82.3òò+óó2.4€€38.5òò+óó7.5ÌòòóóOF04òò1600óóà` ..` àN€€€0.19€€€€0.009€€€1.3€€€€€€€8.0€€€€62.7òò+óó7.8€€34.3òò+óó6.5ÌÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ÏóóÌð'ð€from€Soybase,€based€on€Shoemaker€and€Olson€(1993).Ìð(ð€LOD€is€the€logòò10óó€of€the€odds€ratio€that€supports€evidence€for€€€€Ï€the€presence€of€the€QTL€at€the€locus€from€Mapmaker/QTL€1.1.Ìðð€the€percent€variation€associated€with€the€interval€fromÏMapmaker/QTL€1.1.€ÇÔ€XXXÔÔO€6<þ6X9`("Courier 10cpiOÔÓ  ÓTable€3.€Markers€showing€significant€associations€with€mean€SDSÏdisease€incidence€in€each€of€five€locations.Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Mean€DI€%€for€RILsÌ€€DNA€€€Linkage€€€€€€€€€€€€€€€€€€€€€€€€€QTL€€€€with€alleles€fromÌMarker€€groupð'ð€€Env.ð(ð€€òòRóóòò2óó€€€òòPóó>F€€€LODðð€€€var.ðð€€Essex€€€ForrestÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌòòóóòòóóÌOG13òò490óóà` ..` àA€€€€€V90€€0.16€€0.0001€3.75€€€16€€€65.6òò+óó4.3€€39.5òò+óó4.4Ìòòóó€€€€€€€€€€€€€€€€C91€€0.12€€0.0006€2.73€€€12€€€22.6òò+óó3.2€€€9.2òò+óó1.9Ì€€€€€€€€€€€€€€€€P91€€0.07€€0.0069€1.51€€€€7€€€64.5òò+óó4.0€€48.4òò+óó4.3Ì€€€€€€€€€€€€€€€€C92€€0.18€€0.0001€4.18€€€18€€€74.7òò+óó3.2€€53.6òò+óó3.4Ì€€€€€€€€€€€€€€€€R93€€0.10€€0.0013€2.36€€€10€€€61.7òò+óó4.1€€41.6òò+óó4.3Ì€€€€€€€€€€€€€€€Mean€€0.17€€0.0001€3.97€€€17€€€57.8òò+óó3.2€€38.5òò+óó2.9ÌÌOI03òò450óóà` ..` àA€€€€€V90€€0.24€€0.0001€4.97€€€23€€€70.5òò+óó4.3€€40.0òò+óó4.3Ìòòóó€€€€€€€€€€€€€€€€C91€€0.15€€0.0002€4.1€€€€20€€€24.2òò+óó3.4€€€8.7òò+óó2.1Ì€€€€€€€€€€€€€€€€P91€€0.08€€0.0089€2.18€€€11€€€66.9òò+óó3.9€€50.6òò+óó4.7Ì€€€€€€€€€€€€€€€€C92€€0.17€€0.0001€4.39€€€21€€€75.7òò+óó3.1€€55.4òò+óó3.6Ì€€€€€€€€€€€€€€€€R93€€0.10€€0.0022€2.72€€€13€€€63.7òò+óó4.2€€44.0òò+óó4.6Ì€€€€€€€€€€€€€€€Mean€€0.20€€0.0001€5.11€€€24€€€60.2òò+óó3.2€€39.6òò+óó3.1Ì€€ÌOE04òò450óóà` ..` àG€€€€€V90€€0.30€€0.0017€2.66€€€22€€€73.4òò+óó9.4€€28.4òò+óó8.9Ìòòóó€€€€€€€€€€€€€€€€C91€€0.30€€0.0016€2.52€€€16€€€34.1òò+óó6.8€€€7.4òò+óó3.5Ì€€€€€€€€€€€€€€€€P91€€0.30€€0.0017€2.95€€€24€€€74.4òò+óó8.5€€35.5òò+óó7.4Ì€€€€€€€€€€€€€€€€C92€€0.25€€0.005€€2.22€€€16€€€73.4òò+óó8.0€€40.0òò+óó7.6Ì€€€€€€€€€€€€€€€€R93€€0.27€€0.0033€2.25€€€18€€€71.0òò+óó9.7€€30.7òò+óó8.3Ì€€€€€€€€€€€€€€€Mean€€0.32€€0.0011€3.07€€€21€€€65.3òò+óó7.9€€28.4òò+óó6.4Ì€òòóóòòóó€€òòóóòòóóÌòòóóòòóóOE02òò1000óóà` ..` àG€€€€€V90òòóóòòóó€€0.13€€0.039€€2.49€€€19€€€56.7òò+óó9.3€€33.0òò+óó6.4Ì€€€€€€€€€€€€€€€òòóó€C91€€0.10€€0.072€€2.51€€€20€€€18.1òò+óó5.2€€€7.6òò+óó3.1Ì€€€€€€€€€€€€€€€€P91€€0.16€€0.019€€3.26€€€25€€€65.4òò+óó9.0€€39.5òò+óó6.0Ì€€€€€€€€€€€€€€€€C92€€0.21€€0.006€€2.99€€€21€€€73.6òò+óó7.5€€46.7òòóóòò+óó5.3Ì€€€€€€€€€€€€€€€€R93€€0.15€€0.026€€3.22€€€24€€€57.3òò+óó10.5€31.4òòóóòò+óó5.9€€Ï€€€€€€€€€€€€€€€Mean€€0.19€€0.009€€3.66€€€24€€€54.2òò+óó7.2€€31.6òòóóòò+óó4.6Ìòòóóòòóóòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌð'ð€from€Soybase,€based€on€Shoemaker€and€Olson€(1993).Ìð(ð€€V90,€Villa€Ridge€1990;€C91,€Cora€1991;€P91,€Pulaski€1991;€C92,€Ï€€€Cora€1992;€R93,€Ridgway€1993.Ìðð€€LOD€is€the€logòò10óó€of€the€odds€ratio€that€supports€evidence€for€€€Ï€€the€presence€of€the€QTL€at€the€locus€from€Mapmaker/QTL€1.1.Ìðð€€the€percent€variation€associated€with€the€interval€from€€€€€€€€Ï€€€Mapmaker/QTL€1.1.€ÌÇTable€4.€Intervals€showing€significant€associations€with€mean€SDSÏdisease€severity€across€five€locations.ÌòòóóòòÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Mean€DI€%€for€RILsÌ€€DNA€€€Linkage€€€€€€€€€€€€€€€€€€€€€€QTL€€€€with€alleles€fromÌMarker€€groupð'ð€òòóóòò€Róóòò2óó€€€€òòPóó>F€€€€€LODð(ð€€€var.ðð€€Essex€€€€€€ForrestÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌòòóóòòóóÌòòóóòòóóòòóóOG13òò490óóà` ..` àA€€€0.10€€€0.0013€€2.4€€€€10.5€€€1.57òò+óó0.05€€1.38òò+óó0.03€ÌOI03òò450óóà` ..` à€€€€0.12€€€0.001€€€2.5€€€€11.9€€€1.60òò+óó0.1€€€1.40òò+óó0.1ÌÌOE02òò1000óóà` ..` àG€€€0.24€€€0.0027€€3.61€€€21.5€€€1.62òò+óó0.12€€1.31òò+óó0.04ÌOE04òò450óóà` ..` à€€€€0.39€€€0.0002€€3.37€€€21.3€€€1.80òò+óó0.11€€1.30òò+óó0.05€ÌÌòòóóòòóóòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌð'ð€from€Soybase,€based€on€Shoemaker€and€Olson€(1993).Ìð(ð€LOD€is€the€logòò10óó€of€the€odds€ratio€that€supports€evidence€for€€€€Ï€the€presence€of€the€QTL€at€the€locus€from€Mapmaker/QTL€1.1.Ìðð€the€percent€variation€associated€with€the€interval€fromÏMapmaker/QTL€1.1.€ÌÇÓ  ÓTable€5.€Markers€identifying€two€intervals€showing€significantÏassociations€with€yield€in€SDS€infested€fields.Ìòòóóòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ÏóóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Mean€yield€Ì€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€(kg€haòò„1óó)for€linesÌ€€DNA€€Linkage€€€€€€€€€€€€€€€€€€€€€€€€€€€QTL€€€with€alleles€fromÌMarker€groupð'ð€Env.ð(ð€òò€Róóòò2óó€€€€òòPóó>F€€€LODðð€€€€var.ðð€€Essex€€€ForrestÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ÏóóÌòòóóòòóóÌG13òò490óóà` ..` àA€€€V90€€0.05€€0.026€€€1.16€€€€5.2€€€€2970òò+óó50€€3150òò+óó60Ìòòóó€€€€€€€€€€€€€€C91€€0.00€€0.51€€€€0.14€€€€0.7€€€€5120òò+óó80€€5280òò+óó80Ì€€€€€€€€€€€€€€P91€€0.05€€0.027€€€1.15€€€€5.2€€€€3160òò+óó50€€3350òò+óó60Ì€€€€€€€€€€€€€€C92€€0.12€€0.0005€€2.83€€€12.4€€€€2860òò+óó70€€3210òò+óó70Ì€€€€€€€€€€€€€€R93€€0.08€€0.0004€€1.96€€€€8.7€€€€2900òò+óó60€€3170òò+óó60Ì€€€€€€€€€€€€€Mean€€0.09€€0.0037€€2.01€€€€8.9€€€€3420òò+óó50€€3630òò+óó50ÌÌOI03òò450óóà` ..` àA€€€V90€€0.04€€0.072€€€1.01€€€€5.0€€€€2970òò+óó60€€3130òò+óó60Ìòòóó€€€€€€€€€€€€€€C91€€0.03€€0.124€€€0.67€€€€3.4€€€€5150òò+óó80€€5330òò+óó80Ì€€€€€€€€€€€€€€P91€€0.09€€0.0052€€1.76€€€€8.4€€€€3120òò+óó60€€3370òò+óó60Ì€€€€€€€€€€€€€€C92€€0.17€€0.0001€€4.31€€€20.4€€€€2800òò+óó60€€3220òò+óó80Ì€€€€€€€€€€€€€€R93€€0.07€€0.011€€€2.19€€€10.6€€€€2990òò+óó70€€3140òò+óó60Ì€€€€€€€€€€€€€Mean€€0.12€€0.0012€€2.93€€€13.6€€€€3380òò+óó50€€3640òò+óó50Ì€€€€€€€€€€€€€€€€€€€€€€€ÌÌOE04òò450óóà` ..` àG€€€V90€€0.06€€0.210€€€0.23€€€€òòóó2.0€€€€2850òò+óó90€€3020òò+óó90€€Ï€€€€€€€€€€€€€€C91€€0.02€€0.430€€€0.03€€€€0.2€€€€5100òò+óó170€5300òò+óó180Ì€€€€€€€€€€€€€€P91€€0.08€€0.138€€€0.27€€€€2.3€€€€3110òò+óó130€3370òò+óó110€Ï€€€€€€€€€€€€€€C92€€0.17€€0.022€€€0.73€€€€5.9€€€€2820òò+óó180€3360òò+óó130€Ï€€€€€€€€€€€€€€R93€€0.35€€0.0006€€3.23€€€24.5€€€€2610òò+óó120€3280òò+óó120Ì€€€€€€€€€€€€€Mean€€0.16€€0.028€€€0.84€€€€6.3€€€€3300òò+óó110€3670òò+óó110ÌÌOE02òò1000óóà` ..` àG€€€V90€€0.01€€0.620€€€0.04€€€€0.2€€€€3090òò+óó80€€3010òò+óó110Ì€€€€€€€€€€€€€€C91€€0.01€€0.610€€€0.08€€€€0.6€€€€5200òò+óó100€5310òò+óó150Ì€€€€€€€€€€€€€€P91€€0.08€€0.100€€€0.52€€€€4.1€€€€3050òò+óó130€3320òò+óó90Ì€€€€€€€€€€€€€€C92€€0.20€€0.009€€€1.81€€€13.7€€€€2700òò+óó140€3190òò+óó110Ì€€€€€€€€€€€€€€R93€€0.32€€0.0005€€4.81€€€31.5€€€€2750òò+óó120€3310òò+óó90Ì€€€€€€€€€€€€€Mean€€0.11€€0.006€€€1.33€€€€9.4€€€€3360òò+óó90€€3630òò+óó90Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€ÏóóÌð'ð€from€Soybase,€based€on€Shoemaker€and€Olson€(1993).Ìð(ð€€V90,€Villa€Ridge€1990;€C91,€Cora€1991;€P91,€Pulaski€1991;€C92,€Ï€€€Cora€1992;€R93,€Ridgway€1993.Ìðð€€LOD€is€the€logòò10óó€of€the€odds€ratio€that€supports€evidence€for€€€Ï€€the€presence€of€the€QTL€at€the€locus€from€Mapmaker/QTL€1.1.Ìðð€€the€percent€variation€associated€with€the€interval€from€€€€€€€€Ï€€€Mapmaker/QTL€1.1.ÌÇÒ X ÒTable€6.€Markers€identifying€an€interval€showing€significantÏassociation€with€mean€SCN€index.Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Mean€DI€%€for€RILsÌ€€DNA€€€Linkage€€€€€€€€€€€€€€€€€€€€€€€QTL€€€€€€€€with€alleles€fromÌMarker€€groupð'ð€€òòRóóòò2óó€€€€€òòPóó>F€€€€LODð(ð€€€€var.ðð€€€€€€Essex€€€€€ForrestÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌòòÌóóOG13òò490óóà` ..` àA€€€0.04€€€€0.056€€€0.9€€€€€4.2€€€€€€€3.4òò+óó0.2€€2.7òò+óó0.3ÌOI03òò450óóòòóóà` ..` àA€€€0.14€€€€0.0001€€2.6€€€€12.9€€€€€€€3.8òò+óó0.2€€2.5òò+óó0.3€ÌÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌð'ð€from€Soybase,€based€on€Shoemaker€and€Olson€(1993).Ìð(ð€LOD€is€the€logòò10óó€of€the€odds€ratio€that€supports€evidence€for€theÏpresence€of€the€QTL€at€the€locus€from€Mapmaker/QTL€1.1.Ìðð€the€percent€variation€associated€with€the€interval€from€Mapmaker/QTLÏ1.1.€Çò òó óTable€7.€Marker€genotypes€and€SDS€DI€means€of€RILs€with€the€mostÏresistant€and€least€resistant€phenotypes€based€on€entry€means€overÏfive€locations.Ìòòóó€€òò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Linkage€€Groupð'ðÌ€€€€€€€€€€SDS€€€€€€Yield€€€€€€1G€€€€€€€C2€€€€€€2G€€€€€€€€N€€GenotypeÌ€€€€Line€€€DI€€SCN€kg€haòò„1óó€€G13ð(ðI03€O05€K455€E04€E02€€C01€F04€ScoreððÌ€€òò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óó€€Ï€€€€€€78€€€4.4€€R€€€4120€€€€€-€€+€€€€-€€+€€€€€-€€o€€€€+€€-€€€€4.5Ì€€€€€€59€€€7.2€€R€€€3870€€€€€+€€+€€€€+€€-€€€€€+€€+€€€€+€€+€€€€7.0Ì€€€€€€37€€€7.8€€R€€€3850€€€€€+€€+€€€€+€€+€€€€€+€€+€€€€o€€+€€€€7.5Ì€€€€€€44€€€8.2€€S€€€3760€€€€€+€€o€€€€+€€o€€€€€+€€+€€€€+€€+€€€€7.0Ì€€€€€€57€€€8.8€€R€€€3890€€€€€+€€+€€€€+€€o€€€€€+€€+€€€€+€€+€€€€7.5Ì€€€€€€23€€€8.9€€R€€€3960€€€€€+€€+€€€€+€€+€€€€€-€€+€€€€+€€+€€€€7.0Ì€€€€€€67€€€9.8€€R€€€3920€€€€€+€€+€€€€+€€o€€€€€+€€o€€€€+€€+€€€€7.0Ì€€€€€€47€€10.6€€R€€€3715€€€€€+€€+€€€€+€€+€€€€€-€€-€€€€+€€-€€€€5.0ÌÌ€Forrest€€16.5€€R€€€3760€€€€€+€€+€€€€„€€„€€€€€+€€+€€€€+€€+€€€€6.0Ì€€€€€€Ì€€€Essex€€58.9€€S€€€3330€€€€€„€€„€€€€+€€+€€€€€„€€„€€€€„€€„€€€€2.0€ÌÌ€€€€€€51€€80.7€€S€€€3130€€€€€-€€+€€€€-€€-€€€€€-€€o€€€€-€€-€€€€1.5Ì€€€€€€29€€82.5€€S€€€2460€€€€€-€€-€€€€-€€-€€€€€+€€+€€€€+€€o€€€€3.5Ì€€€€€€39€€83.4€€S€€€2860€€€€€-€€-€€€€+€€+€€€€€-€€-€€€€-€€-€€€€2.0Ì€€€€€€76€€83.5€€S€€€2900€€€€€-€€-€€€€-€€o€€€€€-€€-€€€€+€€o€€€€2.0Ì€€€€€€83€€85.8€€S€€€3020€€€€€-€€-€€€€-€€-€€€€€o€€o€€€€-€€-€€€€1.0Ì€€€€€€80€€88.5€€S€€€3360€€€€€-€€-€€€€-€€+€€€€€-€€o€€€€+€€-€€€€3.5Ì€€€€€€85€€90.8€€S€€€3386€€€€€-€€-€€€€-€€o€€€€€o€€o€€€€+€€+€€€€3.5Ì€€€€€€18€€94.0€€S€€€3272€€€€€-€€-€€€€-€€-€€€€€-€€o€€€€-€€-€€€€0.5Ì€€òò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€ð'ð€from€Soybase,€based€on€Shoemaker€and€Olson€(1993).Ì€€ð(ð€òòóóPresence€of€the€beneficial€allele€at€the€marker€is€+,€absence€is€€€Ï€€€„€and€not€scored€unequivocally€is€o.Ì€€ðð€Genotypic€score€is€the€sum€of€individual€loci€based€on€+€=€1,€o€=€€Ï€€€0.5€and€„€=€0.€ÌÌÇÓÓTable€7.€Marker€genotypes€and€SDS€means€of€RILs€with€the€mostÏresistant€phenotype€based€on€entry€means€over€five€locations.Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€òò€€€€€€€€€€€€€Markers€€€€€€€€€€€€€€€€€€óó€€€YieldÌGenotype€€DI€€SCN€€OPCO1€OPO5e€SFO4h€SFO2c€SG13a€€€€Total€€(bu/ac)Ì€€Ì€ExF59€€€7.2€€€R€€€€€€+€€€€€+€€€€€+€€€€€+€€€€€+€€€€€5+€€€€€€€57.6Ì€ExF44€€€8.2€€€S€€€€€€+€€€€€+€€€€€+€€€€€+€€€€€+€€€€€5+€€€€€€€55.9Ì€ExF57€€€8.8€€€R€€€€€€+€€€€€+€€€€€+€€€€€+€€€€€€€€€€€4+€€€€€€€57.9Ì€ExF23€€€8.9€€€R€€€€€€+€€€€€+€€€€€-€€€€€+€€€€€+€€€€€4+€1-€€€€59.0Ì€ExF67€€€9.8€€€R€€€€€€+€€€€€+€€€€€+€€€€€€€€€€€+€€€€€4+€€€€€€€58.4Ì€ExF47€€10.6€€€R€€€€€€+€€€€€+€€€€€-€€€€€+€€€€€+€€€€€4+€1-€€€€55.3ÌÌForrest€16.5€€€R€€€€€€+€€€€€„€€€€€+€€€€€„€€€€€+€€€€€3+€€2„€€€56.0€€€€ÌEssex€€€58.9€€€S€€€€€€„€€€€€+€€€€€„€€€€€+€€€€€„€€€€€2+€€3„€€€49.5ÌÌÌÌÌÌÌÇ€€òò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Linkage€€Groupð'ðÌ€€€€€€€€€€SDS€€€€€€Yield€€€€€€1G1€€€€€€C2€€€€€€2G€€€€€€€€N€€GenotypeÌ€€€€Line€€€DI€€SCN€kg€haòò„1óó€€G13ð(ðI03€O05€K455€E04€E02€€C01€F04€ScoreððÌ€€òò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óó€€Ï€€€€€€89€€12.5€€2€€€62.3€€€€€+€€ND€€€-€ND€€€€ND€€ND€€€+€€+€€€€5Ì€€€€€€20€€15.6€€3€€€56.4€€€€€-€€-€€€ND€€+€€€€ND€€+€€€ND€€ND€€€6.0Ì€€€€€€55€€17.4€€2€€€59.2€€€€€-€€+€€€€+€ND€€€€€+€€ND€€€+€€+€€€€8Ì€€€€€€32€€18.2€€2€€€54.6€€€€€+€€+€€€€+€€+€€€€ND€€+€€€ND€€ND€€€8.0Ì€€€€€€65€€18.9€€2€€€63.2€€€€€+€€+€€€ND€€+€€€€€+€€+€€€€+€€ND€€€8.0Ì€€€€€€71€€19.0€€2€€€54.9€€€€€-€€ND€€€-€ND€€€€€+€€-€€€€+€€-€€€€5Ì€€€€€€98€€21.7€€1€€€50.6€€€€€+€€+€€€€-€ND€€€€ND€€ND€€€+€€+€€€€6.5Ì€€€€€€64€€21.8€€1€€€57.8€€€€€+€€-€€€€-€ND€€€€ND€€+€€€ND€€+€€€€5.0Ì€€€€€€43€€21.9€€1€€€49.6€€€€€+€€+€€€€+€€+€€€€€+€€+€€€€+€€+€€€€8Ì€€€€€€81€€22.1€€1€€€58.6€€€€€-€€-€€€€+€€-€€€€€+€€+€€€€+€€+€€€€7.0Ì€€€€€€84€€22.5€€2€€€52.2€€€€ND€€ND€€€-€ND€€€€ND€€ND€€ND€€ND€€€3.0Ì€€€€€€11€€24.9€€1€€€53.2€€€€€+€€ND€€ND€€+€€€€ND€€ND€€ND€€ND€€€6.5Ì€€€€€€25€€26.0€€1€€€48.9€€€€€+€€+€€€ND€€-€€€€ND€€+€€€ND€€ND€€€7.0Ì€€€€€€96€€26.2€€1€€€54.5€€€€€-€€-€€€€-€ND€€€€ND€€ND€€ND€€ND€€€4.5Ì€€€€€€93€€28.9€€3€€€48.0€€€€€+€€+€€€ND€€-€€€€ND€€-€€€ND€€ND€€€6Ì€€€€€€92€€29.0€€1€€€47.8€€€€€-€€+€€€€-€ND€€€€ND€€ND€€€+€€+€€€€6.5Ì€€€€€€70€€30.4€€1€€€50.4€€€€€+€€+€€€€-€ND€€€€€+€€ND€€€+€€-€€€€7Ì€€€€€€33€€30.5€€1€€€54.1€€€€€+€€+€€€ND€€-€€€€ND€€+€€€ND€€ND€€€5Ì€€€€€€50€€30.8€€1€€€54.8€€€€€-€€-€€€ND€€+€€€€ND€€+€€€ND€€ND€€€6.0Ì€€€€€€63€€31.8€€1€€€53.5€€€€€+€€+€€€ND€€+€€€€ND€€ND€€ND€€ND€€€7.5Ì€€€€€€58€€32.8€€3€€€54.6€€€€€+€€-€€€ND€€-€€€€ND€€ND€€ND€€ND€€€5.0Ì€€€€€€16€€33.3€€1€€€51.2€€€€€-€€-€€€ND€€+€€€€ND€€+€€€ND€€ND€€€4.0Ì€€€€€€77€€35.1€€1€€€50.3€€€€€+€€+€€€€+€€-€€€€€+€€ND€€€+€€+€€€€8.5Ì€€€€€€95€€36.3€€1€€€55.5€€€€€+€€-€€€€+€ND€€€€ND€€ND€€ND€€ND€€€6.5Ì€€€€€€17€€37.7€€2€€€52.8€€€€€-€€+€€€ND€€+€€€€ND€€-€€€ND€€ND€€€6.0Ì€€€€€€€8€€37.9€€1€€€47.3€€€€€-€€-€€€€-€€+€€€€ND€€ND€€ND€€ND€€€3.5Ì€€€€€€74€€39.4€€1€€€55.7€€€€ND€€+€€€ND€ND€€€€ND€€ND€€ND€€ND€€€4.5Ì€€€€€€28€€40.3€€1€€€58.2€€€€ND€€-€€€€+€ND€€€€ND€€ND€€ND€€ND€€€6.0Ì€€€€€€56€€41.2€€1€€€47.6€€€€€+€€+€€€€+€ND€€€€ND€€ND€€ND€€ND€€€5.5Ì€€€€€€79€€42.5€€1€€€46.6€€€€€+€€-€€€ND€ND€€€€ND€€+€€€ND€€ND€€€6.5Ì€€€€€€97€€43.2€€3€€€61.6€€€€€+€€-€€€€-€ND€€€€ND€€ND€€ND€€ND€€€4.0Ì€€€€€€61€€43.5€€2€€€59.2€€€€ND€€+€€€€+€ND€€€€ND€€ND€€ND€€ND€€€4.5Ì€€€€€€€6€€45.0€€2€€€59.8€€€€€+€€+€€€€+€€+€€€€ND€€ND€€ND€€ND€€€7.5Ì€€€€€€75€€46.0€€2€€€55.6€€€€€-€€-€€€€-€ND€€€€ND€€ND€€ND€€ND€€€4.5Ì€€€€€€31€€47.2€€1€€€46.4€€€€€+€€+€€€ND€€+€€€€ND€€ND€€ND€€ND€€€5.5Ì€€€€€100€€47.5€€1€€€54.9€€€€€-€€ND€€€-€ND€€€€ND€€ND€€ND€€ND€€€5Ì€€€€€€24€€49.3€€1€€€55.0€€€€€+€€+€€€€+€ND€€€€ND€€ND€€ND€€ND€€€7.5Ì€€€€€€87€€49.7€€1€€€53.4€€€€€-€€ND€€€-€€-€€€€ND€€ND€€ND€€ND€€€4.0Ì€€€€€€62€€50.2€€1€€€46.7€€€€€+€€+€€€€-€ND€€€€ND€€ND€€ND€€ND€€€4.5Ì€€€€€€€3€€51.1€€2€€€54.3€€€€€+€€+€€€€-€€+€€€€ND€€ND€€ND€€ND€€€5.5Ì€€€€€€73€€54.6€€1€€€63.2€€€€€+€€+€€€ND€€-€€€€ND€€+€€€ND€€ND€€€5Ì€€€€€€45€€55.3€€1€€€43.7€€€€€+€€-€€€ND€€-€€€€ND€€+€€€ND€€ND€€€6.0Ì€€€€€€14€€55.9€€1€€€51.5€€€€€-€€-€€€€-€€-€€€€ND€€ND€€ND€€ND€€€3.5Ì€€€€€€26€€56.1€€2€€€59.0€€€€ND€€+€€€€-€ND€€€€ND€€ND€€ND€€ND€€€5.5Ì€€€€€€35€€56.4€€1€€€51.5€€€€€-€€-€€€ND€€+€€€€ND€€ND€€ND€€ND€€€5.5Ì€€€€€€52€€58.8€€1€€€56.8€€€€€-€€-€€€ND€€+€€€€ND€€-€€€ND€€ND€€€3Ì€€òò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Linkage€€Groupð'ðÌ€€€€€€€€€€SDS€€€€€€Yield€€€€€€1G1€€€€€€C2€€€€€€2G€€€€€€€€N€€GenotypeÌ€€€€Line€€€DI€€SCN€kg€haòò„1óó€€G13ð(ðI03€O05€K455€E04€E02€€C01€F04€ScoreððÌ€€òò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óó€€Ï€€€€€€€5€€59.4€€2€€€58.5€€€€€+€€+€€€€+€€+€€€€ND€€ND€€ND€€ND€€€7.5Ì€€€€€€72€€59.8€€1€€€50.9€€€€ND€€-€€€€-€ND€€€€ND€€ND€€ND€€ND€€€2.5Ì€€€€€€90€€60.8€€1€€€50.8€€€€€-€€-€€€ND€€-€€€€ND€€+€€€ND€€ND€€€3.0Ì€€€€€€82€€61.8€€1€€€55.3€€€€€-€€-€€€€-€€-€€€€€+€€ND€€€+€€+€€€€3.5Ì€€€€€€42€€62.3€€3€€€51.4€€€€€-€€-€€€€ND€+€€€€ND€€+€€€ND€€ND€€€4Ì€€€€€€€2€€62.6€€2€€€57.0€€€€€-€€-€€€€-€ND€€€€ND€€ND€€ND€€ND€€€2.5Ì€€€€€€15€€64.9€€2€€€45.8€€€€€+€€+€€€€-€€-€€€€€-€€ND€€ND€€-€€€€3Ì€€€€€€€1€€65.4€€1€€€50.1€€€€€+€€+€€€ND€€+€€€€ND€€-€€€ND€€ND€€€7Ì€€€€€€41€€65.5€€1€€€49.1€€€€€-€€-€€€ND€€-€€€€ND€€ND€€ND€€ND€€€4.5Ì€€€€€€88€€67.7€€1€€€48.7€€€€€-€€ND€€€+€ND€€€€ND€€ND€€ND€€ND€€€4Ì€€€€€€38€€68.1€€3€€€47.5€€€€€+€€+€€€ND€€+€€€€ND€€-€€€ND€€ND€€€5Ì€€€€€€30€€68.4€€1€€€47.8€€€€€-€€-€€€ND€€-€€€€ND€€ND€€ND€€ND€€€4.5Ì€€€€€€36€€69.5€€1€€€50.7€€€€€+€€+€€€€+€€+€€€€ND€€ND€€ND€€ND€€€8.0Ì€€€€€€53€€70.1€€1€€€51.2€€€€€-€€-€€€€+€ND€€€€ND€€-€€€ND€€+€€€€3.5Ì€€€€€€19€€70.4€€1€€€52.3€€€€€-€€-€€€€-€€-€€€€€-€€ND€€ND€€-€€€€1.0Ì€€€€€€94€€71.3€€1€€€47.1€€€€€+€€-€€€€-€€-€€€€ND€€ND€€ND€€ND€€€5Ì€€€€€€22€€71.6€€1€€€48.8€€€€€-€€+€€€€+€€-€€€€ND€€ND€€ND€€ND€€€5.5Ì€€€€€€54€€74.5€€1€€€51.6€€€€€-€€-€€€€-€ND€€€€€+€€ND€€€+€€+€€€€4Ì€€€€€€60€€74.9€€1€€€46.7€€€€€-€€-€€€ND€€-€€€€ND€€-€€€ND€€ND€€€4.0Ì€€€€€€99€€75.5€€1€€€51.2€€€€€+€€ND€€€-€ND€€€€ND€€ND€€ND€€ND€€€4.5Ì€€€€€€86€€75.8€€1€€€49.8€€€€€-€€-€€€€-€€-€€€€ND€€ND€€€-€€-€€€€1Ì€€€€€€69€€76.4€€1€€€51.4€€€€€-€€+€€€€-€ND€€€€€-€€ND€€€+€€-€€€€3Ì€€€€€€€9€€76.6€€1€€€46.6€€€€€-€€-€€€€-€€-€€€€€-€€ND€€€-€€-€€€€2.5Ì€€€€€€10€€77.3€€1€€€49.4€€€€€+€€+€€€€-€€-€€€€€-€€ND€€€+€€+€€€€5.0Ì€€€€€€€7€€79.3€€1€€€35.0€€€€€-€€-€€€€+€€+€€€€€-€€ND€€€-€€-€€€€3.0Ì€€€€€€68€€79.6€€1€€€48.0€€€€€-€€-€€€€-€ND€€€€€-€€ND€€€+€€+€€€€5Ì€€€€€€51€€80.7€€1€€€46.6€€€€€-€€+€€€€-€€-€€€€€-€€ND€€€-€€-€€€€1.5Ì€€€€€€29€€82.5€€1€€€36.6€€€€€-€€-€€€€-€€-€€€€€+€€+€€€€+€€ND€€€5.5Ì€€€€€€39€€83.4€€1€€€42.6€€€€€-€€-€€€€+€€+€€€€€-€€-€€€€-€€-€€€€4Ì€€€€€€76€€83.5€€1€€€43.1€€€€€-€€-€€€€-€ND€€€€€-€€-€€€€+€€ND€€€2Ì€€€€€€83€€85.8€€1€€€44.9€€€€€-€€-€€€€-€€-€€€€ND€€ND€€€-€€-€€€€1.0Ì€€€€€€80€€88.5€€1€€€50.0€€€€€-€€-€€€€-€€+€€€€€-€€ND€€€+€€-€€€€4.5Ì€€€€€€85€€90.8€€1€€€50.4€€€€€-€€-€€€€-€ND€€€€ND€€ND€€€+€€+€€€€3.5Ì€€€€€€18€€94.0€€1€€€48.7€€€€€-€€-€€€€-€€-€€€€€-€€ND€€€-€€-€€€€0.5ÌÌÌÇTable€1:€RAPD€markers€and€Linkage€groups€showing€significantÏassociations€with€SDS€response.Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€Linkage€€€€€€€€€€€€€€€€€€€€€€€Percentage€€€Allelic€meansÌProbe€€group€€€€€Ròò2óó€€€€€P>f€€€€LODòò*óó€€€variation€€€€€€E€€€€€€€FÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌLOD€is€the€log€10€of€the€odds€ratio€that€supports€evidence€forÌ€€€€€€€€the€prescence€of€the€QTL€at€the€locus.€ÌÇOld€Table€4.€A€Marker€associated€with€yield€in€SDS€infested€fields.ÌÓ  ÓÓ  Óòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Mean€yield€(kg€haòò„1óó)Ì€DNA€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€for€lines€with€alleles€fromÌòòMarkeróóòòóóòòóóòò€€€Env.ð'ð€€€€€òòRóóòò2óóóóòò€€€€€€òòPóó>F€€€€€€€€Essex€€€€€€Forrest€€€€€€€€€€€óó€€€€Ï€€ÌOC01òò650óó€€€V90ภ..¸ à€€0.31àh..hà0.0008à..à€2547òò+óó128àÈ..Èà€€€3050òò+óó€60Ìà..à€€€€C91ภ..¸ à€€0.05€àh..hà0.2àÀ..Àà€à..à€4891òò+óó222àÈ..Èà€€€5248òò+óó128Ìà..à€€€€P91ภ..¸ à€€0.10àh..hà0.07àÀ..Ààà..à€2943òò+óó168àÈ..Èà€€€3286òò+óó€87Ìà..à€€€€C92ภ..¸ à€€0.34àh..hà0.0004à..à€2291òò+óó114àÈ..Èà€€€3211òò+óó114Ìà..à€€€€R93ภ..¸ à€€0.31àh..hà0.0007à..à€2399òò+óó141àÈ..Èà€€€3144òò+óó€94Ìà..à€€€Meanภ..¸ à€€0.27àh..hà0.002à..à€3016òò+óó155àÈ..Èà€€€3588òò+óó101Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌð'ð€V90,€Villa€Ridge€1990;€C91,€Cora€1991;€P91,€Pulaski€1991;Ì€€C92,€Cora€1992;€R93,€Ridgway€1993.ÇÌOH12òò300óóòòóóà` ..` àAnon1€€€6€€€€0.022€€€1.3€€€€€€€6.1€€€€€42.5òò+óó3.5€€54.7òò+óó3.8ÌOR10òò400óóà` ..` àAnon1€€€4€€€€0.078€€€0.7€€€€€€€3.1€€€€€45.6òò+óó3.3€€54.7òò+óó3.9€ÌÇÌImplications€for€Genetic€Dissection€and€Marker€Assisted€Breeding€€€€€€€ÏThe€markers€A117H,€òòóóOG13òò490óóòòóóòòóó,€OI03òò450óóòòóóòòóó,€OE02òò1000óóòòóóòòóó,€OE04òò450óóòòóóòòóó,€K455D„1,€OO05òò250óó,ÏOC01òò650óó€and€OF04òò1600óó€can€be€used€for€marker€assisted€selection€forÏpartial€SDS€resistance€if€their€effects€on€SDS€response€are€additive.ÏTable€7€shows€that€the€beneficial€alleles€of€the€independentlyÏidentified€QTL€are€frequent€among€the€lines€which€are€more€resistantÏto€SDS€than€Forrest€(Hnetkovsky€et€al.€1995).Ç€ÌÌThis€will€accelerate€the€breeding€of€SDS€resistant€soybean€lines€andÏmay€reduce€the€need€for€field€tests€of€SDS€response,€which€are€slowÏand€expensive.€These€loci€are€currently€being€used€to€determineÏallelic€relationships€among€different€sources€of€resistance,€to€assistÏSDS€resistance€gene€introgression€into€susceptible€germplasm,€and€toÏenable€resistance€gene€pyramiding.Ì€€€€€However,€since€the€currently€identified€favorable€alleles€areÏderived€from€Essex€and€Forrest€their€unequivocal€identification€andÏco„selection€will€be€possible€only€in€restricted€instances,€such€asÏwhen€crossing€with€Essex,€Forrest€or€one€of€their€progeny€lines.€TheseÏloci€may€have€several€alleles,€some€of€which€may€confer€greater€orÏlesser€SDS€resistance€than€the€alleles€carried€by€Essex€and€Forrest.ÏTherefore,€defining€allelic€associations€with€resistance€at€these€lociÏin€a€wider€selection€of€soybean€germplasm€is€important.€Ì€€€€€In€the€future,€through€genetic€dissection,€the€effects€of€singleÏresistance€loci€will€be€determined.€Fòò5:11óó€lines€that€were€derived€fromÏFòò5óó€plants€heterozygous€in€the€region€of€an€SDS€resistance€QTL€areÏheterogeneous€for€the€region,€whilst€individual€plants€within€a€lineÏare€largely€homozygous€within€the€region€by€the€Fòò5:11óó.€LinesÏheterogeneous€for€each€resistance€locus€have€been€identified€and€sub„¼line€populations€extracted€from€forty€individual€plants€within€a€line.ÏWith€these€sub„line€populations€the€genetic€and€physiological€effectsÏof€the€segregation€of€an€individual€resistance€locus€will€be€isolated,Ïthe€region€saturated€with€markers€and€the€QTL€localized€further.€TheseÏstudies€will€provide€a€basis€for€map€based€isolation€of€a€geneÏconferring€partial€resistance€to€SDS.ÌÌò ò€€€€€€€€€€€€€€€€€€€€€€€€€ACKNOWLEDGEMENTSó óÌ€€€€We€thank€Dr€M.€E.€Schmidt€for€developing€the€ExF€progenyÏpopulation.€We€thank€Dr.€R.€Shoemaker€for€the€RFLP€probes€and€someÏparent€RFLP€polymorphism€data.€We€thank€Dr.€P.€Keim€for€much€parentÏRFLP€polymorphism€data.€We€thank€Dr.€D.€Webb€for€some€novel€parentÏRFLP€data€and€verification€of€the€RFLP€polymorphism€data.€We€thank€allÏthe€workers€on€the€SDS€field€team€at€Southern€Illinois€University€atÏCarbondale€from€1987€to€present.€Thanks€to€Dr.€V.€Njiti€and€Dr.€O.ÏMyers€Jr.€for€critical€reading€of€the€manuscript.€This€work€wasÏsupported€in€part€by€grants€from€the€Illinois€Soybean€ProgramÏOperating€Board€Nos.€92„18„125„3,€93„19„132„3,€94„20„143„3.ÇòòÌóóA117H€€€€€A€€€€€V90ÌòòóóOG13òò490€€€óóA€€€€€V90ÌOI03€€€€€€€€€€€€V90Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€R93Ì€€€€€€€€€€€€€€€€R93Ì€€€€€€€€€€€€€€€€R93Ì€€€€€€€€€€€€€€€€€€€ÌOE04òò450óó€€€G€€€€€V90ÌòòóóOE02òò1000óó€€G€€€€€V90Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€R93Ì€€€€€€€€€€€€€€€€R93ÌÇÌA117H€€€€€A€€€€€V90ÌòòóóOG13òò490€€€óóA€€€€€V90ÌOI03€€€€€€€€€€€€V90Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€R93Ì€€€€€€€€€€€€€€€€R93Ì€€€€€€€€€€€€€€€€R93Ì€€€€€€€€€€€€€€€€€€€ÌOE04òò450óó€€€G€€€€€V90ÌòòóóOE02òò1000óó€€G€€€€€V90Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€C91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€P91Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€C92Ì€€€€€€€€€€€€€€€€R93Ì€€€€€€€€€€€€€€€€R93ÌÇ€€€€€€The€locus,€identified€by€RFLP€marker€òòóóK455D,€accounted€for€20%€ofÏthe€total€variation€in€SCN€index,€with€òòPóó€=€0.0007€(Table€6)€based€onÏselective€genotyping€€(n€=€60).€€òòóóThe€RAPD€marker€OO05òò250óó€was€notÏsignificantly€associated€with€DS€(òòRòòóó2óó€=€0.13,€òòPóó€=€0.05)€by€ANOVA€basedÏon€selective€genotyping€(n€=€65).€The€beneficial€allele€for€SCN€race€3Ïresistance€was€derived€from€Essex,€the€SCN€race€3€susceptible€parent.Ì€€€€€€€€Detection€of€an€SCN€race€3€resistance€QTL€from€Essex€wasÏunexpected.€The€locus€might€be€a€product€of€type€II€error€or€traitÏscoring€errors€but€the€strength€of€the€association€makes€thisÏunlikely.€Alternately€the€QTL€may€be€confering€resistance€to€someÏother€component€of€the€SCN€population,€however€the€CI€on€the€standardÏdifferentials€was€less€than€1€(Matthews€et€al.,€1991;€Njiti€et€al.,Ï1996).€Therefore€we€propose€the€locus€was€detected€as€a€result€of€QTLÏmapping€in€RILs€rather€than€earlier€generations.€We€predict€thatÏsimilar€QTL€will€be€detected€in€other€SCN€susceptible€soybeanÏvarieties€as€is€commonly€reported€for€other€disease€resistance€traitsÏwhere€resistance€is€partial€(Bubeck€et€al.,€1992;€Wang€et€al.,€1994;ÏYoung€et€al.,€1994,€Hnetkovsky€et€al.€1995).Ì€€€€€€€€òòóóòòóóòòóóòòòòóóóóòòóó€The€presence€of€an€SCN€race€3€resistance€gene€derived€fromÏEssex€could€explain€the€high€numbers€of€SCN€resistant€lines€detectedÏin€this€cross.€The€existence€of€such€SCN€resistance€loci€may€explainÏthe€over€abundance€of€SCN€resistance€lines€in€other€RIL€progenyÏpopulations,€including€Pyramid€x€Douglas€(Njiti€et€al.,€1996).ÏHowever,€the€use€of€Essex€for€propagating€cyst€populations€(Rao„ArelliÏet€al.,€1992)€and€as€an€SCN€race€3€susceptible€check€variety€(Rao„¼Arelli€and€Anand,€1988)€might€be€complicated€by€such€loci.€In€fact,Ïthe€Essex€allele€effect€was€not€significant€in€the€Fòò2óó€and€Fòò3óóÏgenerations€of€intercrosses€with€several€PIs€including€Peking,€theÏsource€of€SCN€resistance€in€Forrest€(Rao„Arelli€and€Anand,€1988;€Rao„¼Arelli€et€al.,€1992).ÌÇTable€6.€Intervals€and€markers€showing€significant€associations€withÏmean€SCN€index.Ìòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌ€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Mean€DI€%€for€RILsÌ€€DNA€€€Linkage€€€€€€€€€€€€€€€€€€€€€€€QTL€€€€€€€€with€alleles€fromÌMarker€€groupð'ð€€òòRóóòò2óó€€€€€òòPóó>F€€€€LODð(ð€€€€var.ðð€€€€€€Essex€€€€€ForrestÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌòòÌóóOG13òò490óóà` ..` àA€€€0.04€€€€0.056€€€0.9€€€€€4.2€€€€€€€3.4òò+óó0.2€€2.7òò+óó0.3ÌOI03òò450óóòòóóà` ..` àA€€€0.14€€€€0.0001€€2.6€€€€12.9€€€€€€€3.8òò+óó0.2€€3.4òò+óó0.3€ÌÌOO05òò250óóà` ..` àC€€€0.03€€€€òòóóòòóó0.18€€€€0.4€€€€€2.1€€€€€€€2.4òò+óó0.4€€3.1òò+óó0.3ÌòòóóK455Dòò3000óóà` ..` àC€€€0.19€€€€0.0007€€1.0€€€€€5.6€€€€€€€2.5òò+óó0.3€€3.9òò+óó0.7ÌÌòò€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€óóÌð'ð€from€Soybase,€based€on€Shoemaker€and€Olson€(1993).Ìð(ð€LOD€is€the€logòò10óó€of€the€odds€ratio€that€supports€evidence€for€theÏpresence€of€the€QTL€at€the€locus€from€Mapmaker/QTL€1.1.Ìðð€the€percent€variation€associated€with€the€interval€from€Mapmaker/QTLÏ1.1.