Inheritance of Resistance to Sorghum Shoot Fly, Atherigona soccata in Sorghum, Sorghum bicolor (L.) Moench
Abstract
Sorghumproductionisaffectedbyawidearrayofbioticconstraints,ofwhichsorghumshootfly,Atherigonasoccataisthemostimportantpest,whichseverelydamagesthesorghumcropduringtheseedlingstage.Hostplantresistanceisoneofthemajorcomponentstocontrolsorghumshootfly,A.soccata.Tounderstandthenatureofgeneactionforinheritanceofshootflyresistance,weevaluated10parents,45F1’sandtheirreciprocalsinreplicatedtrialsduringtherainyandpostrainyseasons.ThegenotypesICSV700,PhuleAnuradha,ICSV25019,PS35805,IS2123,IS2146,andIS18551exhibitedresistancetoshootflydamageacrossseasons.Crossesbetweensusceptibleparentswerepreferredforegglayingbytheshootflyfemales,resultinginasusceptiblereaction.ICSV700,ICSV25019,PS35805,IS2123,IS2146,andIS18551exhibitedsignificantandnegativegeneralcombiningability(gca)effectsforoviposition,deadheartincidence,andoverallresistancescore.Theplantmorphologicaltraitsassociatedwithexpressionofresistance/susceptibilitytoshootflydamagesuchasleafglossiness,plantvigor,andleafsheathpigmentationalsoshowedsignificantgcaeffectsbythesegenotypes,suggestingthepotentialforuseasaselectioncriteriontobreedforresistancetoshootfly,A.soccata.ICSV700,PhuleAnuradha,IS2146andIS18551withsignificantpositivegcaeffectsfortrichomedensitycanalsobeutilizedinimprovingsorghumsforshootflyresistance.Theparentsinvolvedinhybridswithnegativespecificcombiningability(sca)effectsforshootflyresistancetraitscanbeusedindevelopingsorghumhybridswithadaptationtopostrainyseason.Thesignificantreciprocaleffectsofcombiningabilitiesforoviposition,leafglossyscoreandtrichomedensitysuggestedtheinfluenceofcytoplasmicfactorsininheritanceofshootflyresistance.Highervaluesofvarianceduetospecificcombiningability(2ss),dominancevariance(2sd),andlowerpredictabilityratiosthanthevarianceduetogeneralcombiningability(2sg)andadditivevariance(2sa)forshootflyresistancetraitsindicatedthepredominanceofdominancetypeofgeneaction,whereastrichomedensity,leafglossyscore,andplantvigorscorewithhigh2sg,additivevariance,predictabilityratio,andtheratioofgeneralcombiningabilitytothespecificcombiningabilityshowedpredominance ofadditivetypeofgeneactionindicatingimportanceofheterosisbreedingfollowedbysimpleselectioninbreedingshootfly-resistantsorghums.Mostofthetraitsexhibitedhighbroadsenseheritability,indicatinghighinheritanceofshootflyresistancetraits