Yuzo Futsuhara1 and Hidemi Kitano2
1) Faculty of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464 Japan;
2) Department of Biology, Aichi University of Education, Kariya, Aichi-ken, 448 Japan
A mutant with an inferior rooting ability was found in the progenies of a dwarf mutant line, Fukei 71, treated with 0.3% solution of ethylen imine for two hours at 30°C. The mutant phenotype was characterized by inhibition of root elongation and root number (Fig. 1). Plant height was not affected, remaining almost the same as that of the normal in the early growth stage.
To study the inheritance of this mutant trait, the mutant was crossed with the original line, Fukei 71. The F1 plants were normal and the F2 segregated into 228 normal and 65 weakly rooted plants, giving a good fit to a 3 : 1 ratio (x2=1.24,P=0.2-0.3). This shows that the root-growth inhibition is controlled by a recessive gene, which is symbolized as rt.
In barley, Linde-Laursen (1977) reported a weakly rooted, but otherwise normal-looking mutant in the progeny of a Danish variety 'Bomi' treated with ethylmethane sulfonate, and used gene symbol fer (few roots) for the mutant. In corn, Lorenzoni and Salamin (1970) reported an example of rootless mutant (rt) detectable at the early seedling stage. As far as we know, the mutant reported in this study is the first one for rooting ability in rice. This mutant will be useful for developmental and physiological studies in rice.
Linde-Laursen, Ib., 1977. Barley mutant with few roots. Barley Genetics Newsletter 7:43-45.
Lorenzoni, C. and F. Salamin, 1970. A rt (rootless) mutant detectable at an early seedling stage. Maize Genet. Coop. Newsletter 44:94.