Bifurcate Inflorescence.<p>

Mertens, T. R.<p>

The gene bi, causing bifurcate inflorescence, was reported by T. R.  Mertens
and A.  B.  Burdick in 1954 (Am. Jour.  Bot.  41, 726-732).  In the homozygous
bi f lf j plant this gene produces a striking rosette-type of fasciation.  F2
progenies from crosses of rosette-type by normal segregated for bi, which
appeared to be in linkage group five, 4 units distal to f (gene order bi, f
lf).  More recent F2 data has indicated that there are 11 units Between bi and
f and that the gene order is f, bi, lf.  Testcross data gave six percent
recombination between bi and f with the gene order f, bi, If.<p>

An F3 line from a bi f F2 segregate consisted of 23 bi f plants, 7 bi f lf j,
3 lf j and 1 normal.  The latter two classes must be attributed to
outcrossing. An F3 line from a bi f lf j (rosette-type) F2 segregate produced
35 bi f lf J, 5 bi f and 4 normal plants, the bi f and normal plants being
attributed to outcrossing.<p>

The gene bi was found to occur in certain other stocks possessed by A. B.
Burdick. Two different F2 progenies segregating for bi and f gave the
following results.<p>
<pre>

        E x G  E x B
         F2     F2
      _______________
+  +      39     47
+  f       3      3
bi +       3      0
bi f      28     16
         ___    ___ 
          73     66
</pre>

Since some difficulty has always been encountered in classifying a plant for
the bi trait, each individual inflorescence on the mature plant was examined
and listed as either bifurcate or normal.  A plant was then considered as
being bi only if more than one-half of its inflorescences were bifurcate.<p>

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