简介：Bacterialleafblightofrice(BLB),causedbyXanthomonasoryzaepv.oryzae,isoneofthemostdestructivediseasesinAsianricefields.Ahigh-qualityricevariety,LT2,wasusedastherecipientparent.IRBB21,whichcarriestheXa21gene,wasusedasthedonorparent.TheresistancegeneXa21wasintroducedintoLT2bymarker-assistedbackcrossing.ThreeXooraceswereusedtoinoculatetheimprovedlinesfollowingtheclippingmethod.ElevenBC3F3linescarryingXa21wereobtainedbasedonmolecularmarkersandagronomicperformance.The11linesweretheninoculatedwiththethreeXooraces.Allthe11improvedlinesshowedbetterresistancetoBLBthantherecipientparentLT2.BasedonthelevelofresistancetoBLBandtheiragronomicperformance,fivelines(BC3F35.1.5.1,BC3F35.1.5.12,BC3F38.5.6.44,BC3F39.5.4.1andBC3F39.5.4.23)wereselectedasthemostpromisingforcommercialrelease.Theseimprovedlinescouldcontributetoriceproductionintermsoffoodsecurity.