--Philip S. Stinard
We report the results of a three-point linkage test for cr4, oy and y9 on the short arm of chromosome 10 (Table 1). The linkage test was set up as a modified backcross as indicated in Table 1.
Table 1. Three-point linkage data for cr4, oy and y9.
Testcross: Cr4 Cr4 Oy Oy Y9 Y9 X (Cr4 oy y9/cr4 Oy Y9).
Reg. | Phenotype | No. | Totals |
0 | + oy y9 | 135 | |
cr + + | 179 | 314 | |
1 | + + + | 17 | |
cr oy y9 | 21 | 38 | |
2 | + oy + | 16 | |
cr + y9 | 13 | 29 | |
1+2 | + + y9 | 0 | |
cr oy + | 0 | 0 |
Kernels from the backcross ears were planted in the field, the resulting plants selfed, and the selfed ears scored for y9. Kernel samples from each ear were planted in the sand bench, and the resulting seedlings were scored for cr4 and oy. The following linkage relationship was established: cr4-10.0-oy-7.6-y9. The distance between oy and y9 (7.6cM) is shorter than that reported on the 1991 linkage map (12cM), but the data unequivocally place cr4 distal to oy on the short arm of chromosome 10, in the vicinity of Rp1. The suggested map revision is:
cr4
--Rp1----------oy----------y9--
0
12
24
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