1) Food Crops Research Institute, National Chung Hsing University, Taichung, Taiwan 400;
2) Institute of Botany, Academia Sinica, Nankang, Taipei, Taiwan 115, China
The seed of "naked-grain rice" was made available through the courtesy of Dr.
T.T. Chang (IRRI), which was isolated as a derivative of a "ricexwheat hybrid"
in Fujian, China. Cytological examination showed that the plants had exactly
the same karyotype as of ordinary rice cultivars, and that their peroxidase
and acid phosphatase zymograms were the same as those found in ordinary Indica
cultivars. There was no evidence of any genetic material having been
introduced from wheat. When the naked-grain rice was crossed with 11 rice
cultivars, all data for the F\1\ and F\2\ progenies proved that it was
controlled by a single recessive gene. The gene affected the development of
young panicles at the stage of spikelet differentiation, resulting in
modification of floral morphology such as the elongation of paleas to have a
leaflet-like structure, malformation of pistil, stigma and other floral
organis, redifferentiation of florets from the pedicle, and a low seed setting
rate. These phenotypes are similar to those of the "long-hull sterile" mutant
(Kinoshita et al. 1977), which is controlled by lhs-2 belonging to linkage
group XII. When the naked-grain rice was crossed with the long-hull sterile
strain, the F\1\ plants showed the floral characters of the both parents. This
indicates that the gene for the Chinese naked-grain rice is allelic to lhs-2.
Reference
Kinoshita, T., Y. Hidano, and M. Takahashi, 1977. A mutant 'long hull sterile' found in the rice variety, Sorachi. Mem. Fac. Agr. Hokkaido Univ. 10(3): 247- 268.