Abstract: The genetic mechanism of ss gene controlling expression of spongy seedcoat was proved to fit Mendelian fashion in this paper. It was linked with ah , which showed obvious anthocyaninless ( Hoffman) during seedling stage and located on chromosome 9. Its seedcoat also showed the typical gray white color. The anthocyaninless individuals derived from progeny of the F₂ crossing between 95148 as female parent and Hong 100 as male parent showed higher germinating rate respectively in 39 and 51 hours compared to these individuals with anthocyanin.But the great difference existed among these anthocyaninless individuals which also gave the tendency with low total
germinating rate in 10 days. The germinating rate in 10 days in F₂ population varied from 54 % to 100 %. The results showed that ah gene could improve the prophase seed germinating but it still depended on the seed genotype ,
especially that of the embryo or endosperm. Further , the accumulation of brown pigment in seedcoat was not related with ah 、aw and aa genes. The described characterization of seedcoat in this paper could be directly used to select the progenies as a visual morphological marker.

Key words: Tomato, ss gene, Linkage analysis, Germination