Effects of Ssil Gene Controlling dm-type Internode Elongation Pattern on Lodging Resistance and Panicle Characters in Rice

概要

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The dm-type semi-dwarf mutant DMF-1 is controlled by the semi-dominant gene, Short second internode 1 (Ssil), located in the region within ca. 20cM on the long arm of chromosome 1. In order to elucidate the function this gene in relation to the lodging resistance and panicle characters in various genetic backgrounds, these agronomic characters were investigated by using DMF-1, Reimei (sdl allele), six different F_<10> lines (DML-1 to -6) with homozygous form of Ssil, and their parents. The experimental results showed that all the dm-type lines except for DML-6 (DMF-1×Tan-Ginbozu) whose genotype belonged to the homozygous form of both Ssil and d35, significantly increased the lodging resistance, compared to their respective parents. On the other hand, although DMF-1 reduced seed production because of the high ratio of appearance of hull-cracked kernels, such a negative character had been improved in DML-1 (Kinmaze×DMF-1), DML-2 (Nipponbare×DMF-1) and DML-4 (Sasanishiki×DMF-1). Principal component analysis based on fifteen panicle characters also showed that these three F_<10> lines should be assigned to a group of normal cultivars. These results suggested that it is possible to develop a new semi-dwarf variety for practical use, expressing a high level of lodging resistance associated with the Ssil gene in various genetic backgrounds.