Genetic Analysis of Newly Induced Short-root Mutants in Rice (Oryza sativa L.)

Abstract

Short root mutants of rice (Oryza sativa L.) were isolated and characterized. In seedlings of two short root mutants, RM1 and RM2, root length was 30 to 50 % of the wild type 'Oochikara', while a significant difference was not observed between the mutants and the wild type in plant height, number of roots and number of root hairs. In the root, final cell length in the mutants was about 60 % of the wild type suggesting that the short root phenotype is mainly based on defective cell elongation. In root length, the F1 plants between the mutants and between those and the wild type were short and normal, respectively, while the F2 plants segregated into normal and short, giving a good fit to a 3:1 ratio. The F2 between the mutants did not segregate normal plants. These results show that the short root is controlled by a recessive gene, which is symbolized as srt-1.