Abstract:In this paper,we used normal embryo rice ‘Chao2-10’ and giant embryo rice ‘Shangshida No.5’ as materials.The embryo weight and mass ratio of embryo to brown rice of ‘Shangshida No.5’ were compared with those of ‘Chao2-10’.Then we did the genetic analysis of giant embryo phenotype.Giant embryo gene (GE) of ‘Shangshida No.5’,‘Chao2-10’ and Korea giant embryo rice ‘M-2-565-11-3-B(ge)’ were cloned to analyse their sequence.The expression levels of GE gene in ‘Shangshida No.5’,‘Chao2-10’ were analysed by Real time-PCR with the ‘Nipponbare’ as a control.The results were as follows:(1) Both embryo weight and mass ratio of embryo of brown rice ‘Shangshida No.5’ were significantly larger than these of ‘Chao2-10’ (P<0.01).However,embryo weight of the ‘Chao2-10’ is close to or more than some of the giant embryo rice cultivars reported previously;(2) Giant embryo phenotype of ‘Shangshida No.5’ is controlled by a single recessive gene,which is same to ‘M-2-565-11-3-B(ge)’;(3) GE gene in these three cultivars is also a new GE allele:‘Chao2-10’ has a mutation (gep) in the promoter;‘Shangshida No.5’ has mutations (gec) both in the promoter and CDS;‘M-2-565-11-3-B(ge)’ only has a mutation (geh) in CDS;(4) The expression pattern of the gec in young caryopses was different from other GE alleles reported,which increase steadily from 4 day to 7 day after flowering.This paper first reported two new GE alleles,one is mutated in the promoter,and the other has mutations in both promoter and CDS.