Fig. 2. Linkage map of chromosome 6 showing the loci of fs-1, Hl-a and d-58(t). *Calculated by Kinoshita and Takahashi (1968)
Plant Breeding institute, Faculty of Agriculture, Hokkaido University, Sapporo, 060 Japan.
We have supplemented a new map containing eight loci in chromosome 3 (Fig. 1). Depending on F2 data (Table 1), loci of Mi (Minute grain), An-3 (Awn- 3) were determined and d-20 (hayayuki dwarf) was shifted from chromosome 10.
From the cross between Mi and d-2 (ebisu dwarf), it is obvious that the pleiotropic action of d-2 was also responsible for decreasing of spikelet length interacting with Mi (Table 2). Extremely small grain line will be produced in
Table 1. Linkage analysis for marker genes on chromosome 3
===============================================================================
Gene pair F2 segregation No. of Goodness of fit Recombina-
(A: B)a ======================= plants ====================== tion (%)
AB Ab aB ab Ratio X2 P
===============================================================================
H-343 X H-79,
Mi x bc-1 Obs. 141 15 19 31 206 9:3:3:1 0.9 0.8 18.8+-3.1
Exp. 137.0 17.5 17.5 34.0
N-177 X H-126,
Hg: d-20 Obs. 263 33 50 43 389 9:3:3:1 6.5 >0.05 26.2+-2.7
Exp. 247.4 44.3 44.3 53.0
N-177 X H-343,
Mi:d-20 Obs. 209 67 77 19 372 9:3:3:1 1.6 >0.5 (50)
N-177 X Fusayoshi,
Lk-f:d-20 Obs. 150 44 54 24 272 9:3:3:1 2.0 >0.5 44.3+-4.3
Exp. 157.1 46.9 46.9 21.1
Lk-f:An(t)Obs. 192 2 67 11 272 45:3:15:1 4.3 >O.1 11.3+-5.4
Exp. 200.4 3.6 54.6 13.4
d-20:An(t)Obs. 196 8 63 5 272 45:3:15:1 1.0 >0.7 38.3+-9.2
Exp. 193.5 10.5 61.5 6.5
===============================================================================
a: Linkage phase is coupling for all crosses.
Table 2. Comparison of grain size between four phenotypes in F2 population of
the cross, H-343 x H-79
==============================================================================
Phenotype Mi+ Mi d-2 + + +d-2
==============================================================================
Spikelet length 4.54+-0.36a 4.11+-0.23 5.67+-0.32 4.76+-0.23
(80)b (72) (100) (84)
Spikelet width 3.39+-0.14 3.29+-0.18 3.49+-0.13 3.43+-0.17
(97) (94) (100) (98)
==============================================================================
a: Mean+-S.D.(mm), b: Percentage to normal type (++).
Table 3. Segregation patterns between d-58(t) and two other marker genes
==============================================================================
Gene pair F2 segregation No. of Goodness of fit Recombina-
(A:B) ====================== plants ===================== tion (%)
AB Ab aB ab Ratio X2 P
==============================================================================
N-172 X H-69(Repulsion),
d-58:fs-1 Obs. 216 77 74 3 370 9:3:3:1
Exp. 190.1 87.4 87.4 5.1 7.7 0.05 23.4+-4.9
N-172 X H-156(Coupling),
Hl-a:d-58 Obs. 78 8 7 10 103 9:3:3:1
Exp. 68.5 8.7 8.7 17.1 4.6 0.1 18.6+-4.3
ML-100 X N172(Coupling),
Hl-a:d-58 Obs. 116 15 13 19 163 9:3:3:1
Exp. 106.9 15.3 15.3 25.5 2.7 0.4 21.0+-3.7
N-172 X N-156 & ML-100 X N172(pooled),
Hl-a:d-58 Obs. 194 23 20 29 266 9:3:3:1
Exp. 175.5 24.0 24.0 42.5 6.9 0.05 20.1+-2.8
==============================================================================
the progeny of this cross.
In chromosome 6, it was found that d-58(t) for sniall grained dwarf newly assigned to this group (Table 3). Depending on F2 data, the position of the three genes, fs-1 (fine stripe-1), Hl-a (one of the complementary genes for hairy leaf) and d-58(t) was estimated as shown in Fig. 2.
Fig. 2. Linkage map of chromosome 6 showing the loci of fs-1, Hl-a and
d-58(t).
*Calculated by Kinoshita and Takahashi (1968)
References
Khush, G. S., R. J. Singh, S. C. Sur and A. L. Librojo, 1984. Primary trisomics of rice. Origin, morphology, and use in linkage mapping. Genetics 107: 141-163.
Kinoshita, T. and M. Takahashi, 1968. Supplemental report on genes responsible for pubescence of glumes and leaves in rice plant. Genetical studies on rice plant, XXXII.- J. Fac. Agr. Hokkaido Univ. 6: 364-370. (Japanese/English)
Kinoshita, T., M. Takahashi, K. Mori and N. Shinbashi, 1974. Character expression and inheritance mode of three kinds of dwarf rice. -Genetical studies on rice plant, LXI.- Res. Bull. Farm Hokkaido Univ. 19: 64-75. (Japanese/English)
Takamure, I. and T. Kinoshita, 1986. A temperature-sensitive dwarf mutant showing haploid- like features in rice. RGN 3: 99-100.
Takamure, I. and T. Kinoshita, 1990. Linkage analysis for Fusayoshi long-grain gene (Lk-f ) in chromosome 3. RGN 7: 110-111.