14. Linkage analysis in chromosomes 3 and 6

Itsuro TAKAMURE and Toshiro KINOSHITA

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 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.

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
==============================================================================


 


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.