RFLP markers were employed to test whether the individuals possess wide compatibility genes (WCGs) in the progenies of Dular, which is one of the typical wide compatibility varieties in ecotype Aus rice. Meanwhile the characteristics of WCGs were also analysed. The results are shown as follows: (1) the effect of WCG at S-5 locus is better than the others, (2) the combination of different wide compatibility loci is obviously effective in increasing the spikelet fertility, (3) intraallelic interaction can cause japonica macrospore abortive, while interallelic interaction has some effects in fertility expression.