Throughrecurrentbackcrossingincombinationwithmolecularmarker-assistedselection(MAS),restorerlinesR8006andRl176carryingXa-21,agenehavingbroad-spectrumresistancetoricebacterialleafblight,wereselected.BycrossingthetwolinestoCMSlineZhong9A,twonewhybridricecombinations,Zhongyou6andZhongyou1176weredeveloped.Thehybridsshowedhighresistancetodiseases,goodgrainqualityandhighyieldingpotentialinnationalandprovincialadaptabilityandyieldtrials.