Plant Breeding Institute, Faculty of Agriculture, Hokkaido University Sapporo, 060 Japan
Fusayoshi, a Japanese long-grain variety, possesses an incompletely dominant gene, Lk-f, for its long grain. It is known that Lk-f is linked with the genes for awnedness (Takeda and Saito 1980), Mi (minute grain) and be-1 (brittle culm-1), which belong to chromosome 3 (Takamure and Kinoshita 1983).
In order to identify the locus of Lk-f on chromosome 3, F2 populations from three crosses, H-79 (with bc-1) X Fusayoshi, H-504 (with dl for drooping leaf) X N-173 (with Lk-f), and H-726 (with lhs-1 for leafy hull sterile) XFusayoshi were studied. The result showed the linkage of Lk-f with the three genes, bc-1, dl and lhs-1, although the recombination value between Lk-f and dl was not reliable
Table 1. Linkage relations between Lk-f and three markers of chromosome 3 (Phase of linkage-cousling in all crosses)
=================================================================== Genes # F2 plants with phenotype: Recombi. Cross A:B =========================== value(%) AB Ab aB ab Total =================================================================== H-79XFusayoshi Lk-f:bc-1 Obs.204 31 21 46 302 19.5+-2.6 Cal.199.9 26.6 26.6 48.9 H-504XN-173 Lk-f:dl Obs. 40 9 12 7 68 37.4+-7.7 Cal. 40.7 10.3 10.3 6.7 H-726XFusayoshi Lk-f:lhs-1 Obs.396 96 84 60 646 36.9+-2.5 Cal.387.3 97.2 97.2 64.3 =================================================================== bc-1 brittle culm-1 dl-drooping leaf lhs-1 leafy hull sterile-1 Lk-f Fusayoshi long grain
because of a small size of the F2 population (Table 1). The order of the four loci was estimated as shown in Fig. 1.
References
Iwata, N. and T. Omura, 1971. Linkage analysis by reciprocal translocations method in rice plants, I. Linkage groups corresponding to the chromosome 5, 6, 8, 9, 10 and 11. Sci. Bull. Fac. Agr. Kyushu Univ. 25: 137-153. (Japanese/English)
Mori, K., T. Kinoshita and M. Takahashi, 1973. Linkage relationships of genes for some mutant characters of rice kept in Kyushu University. Genetical studies on rice plant, 55. Mem. Fac. Agr. Hokkaido Univ. 8(4): 377-385. (Japanese/English)
Takamure, I. and T. Kinoshita, 1983. Genetical relation between Lk-f and Mi genes concerning with grain size. Genetical studies on rice plant, 87. Mem. Fac. Agr. Hokkaido Univ. 14: 1-10. (Japanese/English)
Takeda, K. and K. Saito, 1980. Major genes responsible for grain shape in rice. Jpn. J. Breed. 30: 280-282. (in Japanese)