5. Linkage analysis of gene Aph for apiculus hair length

Yo-Ichiro SATO, Ryuji ISHIKAWA and Hiroko MORISHIMA

National Institute of Genetics, Misima, 411 Japan

A dominant and a recessive gene at the Aph locus controlling apiculus hair length were found in F4 lines of an Indica (f.145)X Japonica (T65) cross (Sato 1985). Aph carriers and aph homozygotes in the F4 lines had apiculus hairs longer and shorter than 0.7 mm, respectivey, although variation was continuous in the F2 population.

The F2 plants derived from this cross were examined for apiculus hair length and alleles at Est-2 and Pgi-2 loci on the 6th chromosome (1st linkage group). The distribution of apiculus hair length were compared between homozygotes

Table 1. Frequency distribution in apiculus hair length among F2 
plants with alleles at Est-2 and Pgi-2 loci on the 6th chromosome
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                      Apiculus hair length (mm)
Locus  Allele        ________________________________Total  Mean
                      1  .3  .5   .7  .9  1.1  1.3          (mm)
_________________________________________________________________              Est-2  1 1 & hetero.  2  10  24  1.1   3         1     51  0.52
       nul nul*       1   1   5   10   6    4          27  0.73
Pgi-2  2 2 & hetero.  1   4  13    5   2    3          28  0.59
       I I*           1       3    9   4    1          18  0.76
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*Japonica-derived allele.
for Japonica-derived alleles (Est-2nu1 and Pgi-21, respectively) and hetero- and homozygotes for Indica-derived alleles (Est-21 and Pgi-21), as the variation in apiculus hair length was continuous (Table 1). Mean apiculus hair length in homozygotes for the Japonica-derived alleles was longer than that for other genotypes, indicating that the Aph locus is located on the 6th chromosome and is linked with Est-2 and Pgi-2.

References

Sato, Y. E., 1985. Genetic control of apiculus hair length. RGN 2: 72-74.