Linkage between ms\17 and l\1.<p>

Robinson, R. W.<p>

The discovery of the first linkage with a male sterile gene was the fortuitous
result of crossing ms\10 with MacArthurs line d\1-a\1-c-l\1-r-y and noting
that F2 plants selected for a particular phenotype of marker genes did not
segregate for the male sterile gene in the expected ratio (Rick, TGC 2:8).  An
apparent case of linkage with ms\17 has very surprisingly been found in the
same way.<p>

C. M. Rick crossed ms\17 plants with the same multiple recessive line and
backcrossed an F2 plant homozygous recessive for ms\17-d\1-a\1-c-l\1 with an
F1 plant heterozygous for these five genes.  Seeds of this backcross
generation (family LA 321) were very kindly given to me by Rick for use in a
study of seed production by isolated male sterile plants.  A population of 152
backcross plant was grown to the seedling stage but only the twelve plants
which were recessive for a\1 and dominant for d\1, c, and l\1, were
transplanted to the field where classification could be made for ms\17.  The
segregation of 3 fertile: 9 male sterile differed from the expectd 1:1, but
the difference was not quite significant (p=.05-.10).  Another planting was
made of the same backcross and all plants were classified for ms\17 to
determine if the aberrant segregation was due to chance or to linkage between
ms\17 and d\1, c, or l\1.  The following data indicate that good fits to the
expected 1:1:1:1 were obtained between ms\17 and d\1 and c, but crossing over
of 31.5 +- 4.8% occurred between ms\17 and l\1.<p>
<pre>
                                                  Contingency
         + +   + tester  ms\17 +   ms\17 tester   chi-square

ms\17-d   28      18      23           24            1.3
ms\17-c   17      29      24           23            1.9
ms\17-l   17      34      29           12           12.7**
</pre>

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