Genetic Analysis of a Dominant Dwarf Mutant in Rice (Oryza sativa L.)

【Objective】Selection and genetic characterization of a dominant dwarf mutant in rice were made.【Method】A dwarf mutant was identified from a T-DNA insertion population derived from a japonica rice variety,Wuxiangjing 9.Molecular characterization and genetic analysis was conducted of the mutant and its related genetic populations.【Result】Genetic analysis of the mutant showed that two kinds of phenotype,such as dwarf and normal height plants in the segregating population derived from the T-DNA insertion heterozygote plant.They were fit for the ratio of 3(dwarf type):1(normal type),indicating the dwarf gene is dominant mutation.The dwarf gene was further mapped on rice chromosome 4 using a segregation population derived from the mutant crossed with an indica rice variety,Longtepu.Test for HPT resistance showed the dwarf plants were all resistant while the normal height plants were susceptive,and the ratio of resistance and susceptible plants was 3:1,indicating that the dwarf mutation was co-segregating with HPT resistance.These results were consistent with only one copy exogenous gene which was detected in the transgenic rice genome revealed by Southern analysis.【Conclusion】The rice dwarf mutant phenotype is controlled by a dominant gene mutation,which is caused by T-DNA insertion.