Kerr, E. A. High pigment, (hp), is on chromosome 12.
High pigment tomatoes have been used extensively in breeding programs because of their dark color and
high content of vitamins A and C. Tests to determine the chromosomal location of hp have been under way since
1954 (TGC 5:20).
I have not detected linkage closer than 45 units between hp and the following genes: br-y-scf-dgt-in-irr-imb-
per , bk-wv-o-aw,-v-2-d, r-wf-bls-sf, clau-e-ls, mc-tf-wt-at, yv-m-2-c-sp-og, gs-pst-bs-2-not, 1-tp-dl-glau-gf-al, ah-
marm-Nr, u-Xa-3-h-1-2-t-ag, j-2-j-1-hl-a-f, cjf, cu-2, dp, fu, gq, Gr, gra, lc, lg-pe, rvt, ug. There were suggestions of
linkage between hp and sy and between hp and af, but in view of the negative results with other genes on
chromosomes 3 and 5 and the difficulty of scoring hp in the presence of af these results are believed to be spurious.
Table 1 gives data for crosses of hp with genes on chromosome 12. They indicate that hp, aud and yg-2 are
all on the short arm of this chromosome and that they are beyond alb. These limited data suggest that the order is
hp-yg-alb with aud close to yg-2. Data from 3-point crosses are needed to confirm the linkage and to establish their
order.
Kerr, E. A. Linkage tests with gracilis (gra).
Gracilis is a tiny mutant that Stubbe found after irradiation. Usually there is a slight deficiency of mutants in
segregating populations. In tests going back to 1960 no close or consistent linkage has been found with y, r-wf-sy-
sf, clau-e, mc-sd-tf-wt, gs-pst, 1-gf-al, u-h-t,
j-2-j-a, hp-aud-alb, rvt, pe, gq, ug. There was a suggestion of linkage
with glo in repulsion. This was probably spurious as repulsion, coupling, and backcrosses with e showed 46% or
more.
There were suggestions of linkage with d on chromosome 2, m-2 on chromosome 6, and marm on
chromosome 9. The ratios with d were more consistent than with the other genes, and consequently I think gra is
towards the centromere of chromosome 2. Further tests are still needed but a lot of possibilities have been
eliminated.
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