Breeding Rice Lines Possessing Brown Planthopper,bacterial Blight And Blast Resistance And Aroma Characters By Marker Assisted Selection

Rice brown planthopper(BPH),bacterial blight(BB)and blast are main pests and diseases of rice and aroma is an important trait to rice quality.It is of profound significance for rice safety production,ecological protection,cost reduction,efficiency improvement and rice quality improvement by use of superior genes to develop resistant-and aroma-pyramided lines.In this study,brown planthopper resistance genes Bph3,Bph24(t),Bph36,rice bacterial blight resistance gene Xa23,rice blast resistance gene Pita and aroma gene Bah2 were introduced into the main rice varieties by hybridization,backcross and marker-assisted selection.17 Bph24(t),1 Bph36,12 Bph3,21 Pit A,14 Xa23 and1 Badh2 introgressed lines were obtained.And 1 Bph24(t)+Bph36,1 Bph24(t)+Xa23,9 Bph36+Pita,3 Xa23+Pita,2 Pita+badh2 two gene-pyramided lines and 1Bph24(t)+Xa23+Pita,2 Bph24(t)+Bph36+Pita and 1 Bph36+Pita+badh2 three gene-pyramided lines were developed.The results of evaluation by artificial inoculation and infestation of insect pests and diseases showed that the resistance of BPH24(t)and BPH36 introduced lines to rice brown planthopper reached the level of resistance(R)and near to high resistance(HR).The target gene Xa23 introduced and pyramided lines were highly resistant(HR)to rice bacterial blight.The resistance of target gene Pita introduced and pyramided lines to rice blast reached the R level.The resistance level of the pyramided lines possessing the target gene BPH24(t)and BPH36 were stronger than that of the BPH24(t)or BPH36 single gene introduced lines.The introduced and pyramided lines of the target gene badh2 showed different degree of aroma characteristics.The results showed that gene pyramiding had an additive effect on the resistance level of rice brown planthopper,and the functional effects of multi-target genes were not interfered with each other.Agronomic traits analysis showed that the bred pyramided lines are excellent in agronomic characters,pyramiding multi-resistance and fragrance genes can still develop breeding lines with good economic characters,and the developed introduced and pyramided lines in this study have important application prospect in breeding new type of efficient,high-quality and green rice varieties and can provide a good material foundation for rice breeding.