Identification and Genetic Analysis of dl,a Dwarf Mutant of Tomato

Mutants are important materials for investigating plant gene function and developing new crop variety. In our previous study,a non-function of the transgene and stably inherited dwarf mutant dl( dwarf line) was found in the progenies of transgenic tomato. To elucidate the phenotypic and genetic characteristics of this mutant,the differences in phenotype between the mutant dl and wild type LA4024 in different growth stages were comparatively analyzed in the present study. Compared with the wild type, the dl mutant showed shorter internodes, dwarf, more branches,underdeveloped roots,and all tissues and organs of the mutant plant become smaller,including leaf,flower,fruit,and seed. The plant height of the dwarf mutant dl could be recovered by exogenous spray application of gibberellin,but not influenced by exogenous application of auxin,suggesting dl is a gibberellin-deficient mutant. Genetic analysis of F1,F2,and BC1 population derived from the cross dl / LA4024 revealed that the mutant phenotype of dl was controlled by a single recessive gene. These results laid a basis for mapping,cloning and functional analysis of the dl gene.