Abstract: Using 247 RFLP markers distributed on 12 chromosomes combined with 8 kinds of restriction enzymes, null allelism were analyzed in "Nanjing 11" (Oryza sativa L. ssp. indica ), "Kinmaze ge mutant" ( O. sativa L. ssp. japonica ) and "Bellemont" ( intermediate type). Nine probes showed null allelism, among which RG573, G93, G122, G402 and G1318 were specific for "Nanjing 11" ,G261 for "Kinmaze ge mutant", RG229 for "Bellemont", C397 for both "Nanjing 11" and "Bellemont", and RG131 for "Bellemont" and "Kinmaze ge mutant". The null allelic genotype and the indica or japonica phenotype of each individual in the segregation population ("Nanjing 11 "/Kinmaze ge mutant) was described by using 7 null allelic RFLP markers and morphological index characters. The null allelic RFLP markers displayed dominant inheritance in the F2 population, T-test showed that the t-values of G93,G122,G1318 and G397 were extremely significant,and the t-values of G261 and RG573 were also quite significant, indicating that null allelic probes could be used for identifying indica and japonica rice specifically.

Key words: Rice, RFLP, Null allele, Morphological index