Twomajorbacterialblight(BB)resistancegenes(Xa21andxa13)andamajorgeneforblastresistance(Pi54)wereintrogressedintoanIndianricevarietyMTU1010throughmarker-assistedbackcrossbreeding.ImprovedSambaMahsuri(possessingXa21andxa13)andNLR145(possessingPi54)wereusedasdonorparents.Marker-assistedbackcrossingwascontinuedtillBC2generationwhereinPCRbasedfunctionalmarkersspecificfortheresistancegeneswereusedforforegroundselectionandasetofparentalpolymorphicmicrosatellitemarkerswereusedforbackgroundselectionateachstageofbackcrossing.SelectedBC2F1plantsfrombothcrosses,havingthehighestrecoveriesofMTU1010genome(90%and92%,respectively),wereintercrossedtoobtainintercrossF1(ICF1)plants,whichwerethenselfedtogenerate880ICF2plantspossessingdifferentcombinationsoftheBBandblastresistancegenes.AmongtheICF2plants,seventriplehomozygousplants(xa13xa13Xa21Xa21Pi54Pi54)withrecurrentparentgenomerecoveryrangingfrom82%to92%wereidentified.AllthesevenICF2plantsshowedhighresistanceagainstthebacterialblightdiseasewithalesionlengthsofonly0.53–2.28cm,1%–5%diseaseleafareasanddiseasescoringvaluesof‘1'or‘3'.ThesevenICF2plantswereselfedtogenerateICF3,whichwerethenscreenedforblastresistance,andallwereobservedtobehighlyresistanttothediseases.SeveralICF3linespossessinghighlevelofresistanceagainstBBandblast,coupledwithyield,grainqualityandplanttypeonparwithMTU1010wereidentifiedandadvancedforfurtherselectionandevaluation.
