Phenotypic Analysis And Fine Mapping Of A Recessive-Dwarf Mutant In Rice

Rice (Oryza sativa L.) is one of world’s most important crops. Plant height is an important agronomic trait, which should be considered in breeding program.The utilization of gibberellin synthesis-related semi-dwarf gene sdl caused well-known rice "green revolution." Although there are many reports of dwarf mutants, but many of recessive dwarf mutants are linkage with bad traits, and the dominant dwarf mutant is not reported much, resulting in few source of dwarf genes,so discovering novel plant height-related gene is still crucial to plant-type breeding. The material used in this study orignated from tissue culture progeny of a Japanica varieties Kitaake. After a series of experiment conducted, we obtained the following results:1. Related to the wild-type plant height (～67.2cm), mutant is about38.6cm high, in additon to a fragile stem, smaller leaves, less, narrow and lightened grain. All the internodes of mutant were shortened propotional compared to wide type, corresponding to a dn-type dwarf mutant.2. Based on the elonged length of second leaf sheath treated with exogenous applied of gibberellin, the result suggested that GA biosynthetic pathway in mutant is not been affected.3. Observed from the stem tissue sections, we found there was less vascular number in mutant, Longitudinal sections indicated the mutant had shorter cells length.4. Genetic analysis showed that the dwarf trait is decided by a recessive gene. Using the F2, F3, F4population of mutant/PA64and a number of SSR and InDel markers, The mutated gene was mapped into an168KB interval on chromosome4. Predicted through the online system of the rice genome annotation, a total of29open reading frames were involved. This study makes a good intiation to colne this gene.