| Vol. 6 |
Nobuo IWATA, Hikaru SATOH and Atsushi YOSHIMURA
Faculty of Agriculture, Kyushu University, Hakozaki, Fukuoka, 812 Japan
Based on conventional linkage analysis and experiments with reciprocal translocations and trisomics, we have so far reported nine marker genes belonging to linkage group X which corresponds to Nishimura's chromosome 8, i.e., bl-1 (brown leaf spot-1), bc-3 (brittle culm-3), d-29 (short uppermost-internode dwarf), d-30 (waisei-shirasasa dwarf), d-32 (dwarf Kyushu-4), gh-2 (gold hull-2), gh-3 (gold hull-3), spl-2 (spotted leaf-2) and tri (triangular hull) (Iwata and Omura 1971, 1977, 1984; Iwata et al. 1978, 1984). However, an elaborate linkage map with gene order of these genes has not been obtained as yet.
Linkage relations were observed between some of these marker genes and a newly induced chlorina mutant obtained by treating fertilized egg cells with N- methly-N-nitrosourea (MNU). The mutant showed yellowish leaves throughout the growing period and the recessive gene it carries was assigned the gene symbol chl-10. The linkage relations between chl-10, gh-3 and d-32 and with other marker genes on the same chromosome are given in Table 1. The loose linkage relation between gh-3 and d-32 with a recombination value of 38.3% was reconfirmed by using translocations. The sequence of the 10 genes including chl-10 has thus been clarified and the linkage map obtained is shown in Fig. 1.
Table 1.Linkage relations of three genes with other marker genes
on Nishimura's chromosome 8 (linkage group X)
________________________________________________________________
Segregation mode in F2
Gene pair Phase ________________________Recombination value(%)
AB Ab aB ab Total
________________________________________________________________
chl-10-d-29 C 681 132 175 118 1106 33.7±1.8
-tri R 66 25 28 2 121 27.9±8.3
-bc-2 C 615 73 67 132 887 18.0±1.5
-bl-1 R 291 115 122 2 530 14.3±4.2(19.5±3.O)R,F3
-gh-3 R 537 218 217 4 976 14.9±3.1(15.4±1.8)R,F3
-d-32 R 256 85 92 13 446 38.4±4.0(41.0±3.3)R,F3
-gh-2 R 130 44 42 3 219 30.3±6.1
-spl-2 R 246 75 71 9 401 39.3±4.2
gh-3-d-29 R 400 164 114 23 701 39.8±3.1
-tri C 784 194 187 122 1287 36.9±1.8(36.9±1.7)C,R
R 90 25 42 5 162 37.4±6.7
-bc-3 R 406 150 152 1 709 9.9±3.7(12.0±3.1)R,F3
-bl-1 C 1446 255 275 295 2271 27.2±1.1(26.8±1.1)C,R
R 202 94 102 4 402 19.5±4.8
-d-32 C 1435 325 337 189 2286 37.6±1.3(38.3±1.2)C,R
R 467 162 151 29 809 41.9±2.9
-d-30 R 224 76 67 9 376 37.9±4.4
-spl-2 R 106 23 28 15 172 62.2±4.9
d-32-d-29 R 186 56 56 21 319 53.1±4.1
-tri R 663 196 228 68 1155 50.1±2.2
-bc-3 R 229 73 57 26 385 54.9±3.6
-bl-1 R 1259 390 373 129 2151 48.4±1.6
-d-30 R 278 110 139 4 531 18.2±4.2
-gh-2 R 621 248 211 42 1122 40.2±2.5
________________________________________________________________
C:Coupling, R: Repulsion
Values in parentheses: Weighted means calculated from F2 and F3
data, or from coupling and repulsion F2 data.
In this note, the symbols for three dwarfing genes, d-29, d-30 and d-32, recommended by RGC, are used in place of our original symbols, d-K-1, d- W and d-K-4, respectively.
References
Iwata, N. and T. Omura, 1971. Linkage analysis by reciprocal translocation method in rice plants (Oryza sativa L.) II. Linkage groups corresponding to the chromosomes 5, 6, 8, 9, 10 and 11. Sci. Bull. Fac. Agr., Kyushu Univ. 25: 137-153 (in Japanese with English summary).
Iwata, N. and T. Omura, 1977. Linkage studies in rice (Oryza sativa L.) On some mutants derived from chrnic gamma irradiation. J. Fac. Agr., Kyushu Univ. 21: 117-127.
Iwata, N. and T. Omura, 1984. Studies on the trisomics in rice plants (Oryza sativa L.) VI. An accomplishment of a trisomic series in japonica rice plants. Jpn. J. Genet. 59: 199-204.
Iwata, N., T. Omura and H. Satoh, 1978. Linkage studies in rice (Oryza sativa L.). On some mutants for physiological leaf spots. J. Fac. Agr., Kyushu Univ. 22: 243-251.
Iwata, N., H. Satoh and T. Omura, 1984. The relationships between chromosomes identified cytologically and linkage groups. RGN 1: 128-132.
| Vol. 6 |