Table 1. Three-point linkage data for pr1 - lw3 - v2.
Testcross: (Pr1 lw3 V2 Lw4 / pr1 Lw3
v2
Lw4) X Pr1 Lw3 V2 lw4.
|
Phenotype | No. | Totals |
0 | pr1 + v2 | 117 | |
+ lw3 + | 104 | 221 | |
1 | pr1 lw3 + | 23 | |
+ + v2 | 31 | 54 | |
2 | pr1 + + | 74 | |
+ lw3 v2 | 84 | 158 | |
1+2 | pr1 lw3 v2 | 5 | |
+ + + | 5 | 10 |
% recombination pr1--lw3 = 14.4 +/- 1.7
% recombination lw3--v2 = 37.9 +/- 2.3
% recombination pr1--v2 = 52.4 +/- 2.4
The results of a three-point linkage test for pr1, lw3, and v2 on the long arm of chromosome 5 are reported in Table 1. The linkage test was set up as a modified backcross as indicated in Table 1. Since lw3 and lw4 are a duplicate factor pair, the backcross to lw4 was necessary in order to score for lw3 in the next generation. Kernels from the backcross ears were planted in the field, the resulting plants self-pollinated, and the selfed ears scored for pr1 and lw3. Kernel samples from each ear were planted in the sand bench, and the resulting seedlings were scored for lw3 (for confirmation of kernel phenotype) and v2. The following linkage relationship was established: pr1 - 14.4 - lw3 - 37.9 - v2. The distance between pr1 and v2 (52.4 cM) is longer than that reported on the 1993 linkage map (40 cM). The placement of lw3 14 cM distal to pr1 is consistent with the F2 data of Tulpule (Am. J. Bot. 41:294-301, 1954), which gives a pr1 - lw3 distance of 19 cM. The following map revision is suggested:
lw3
--pr1-----ys1------------------got2-------v2--
67
75
96 107
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