The dark red, dr, and black shoulder, bs, genes of the Black Queen tomato.<p>
          
Kerr, E. A.<p>

Black Queen (Webb special) is a very late tomato whose fruits have an
exceptionally dark internal color.  The immature fruits have an intensely dark
green shoulder.  The dark red color of this variety would be of great
importance in canning and market varieties for northern regions.<p>

The F1 between Black Queen and commercial varieties is intermediate for dark
red and black shoulder.  Furthemore both of these characteristics are
influenced by the shading and maturity of the fruit.  Consequently it is
somewhat difficult to identify accurately the various segregates.  The gene,
bs, modifies the color of green shouldered varieties only: bs u and + u have
the same phenotype.<p>

F2's of the crosses Black Queen x Wisconsin 55 and Black Queen x Red Jacket
were grown. The Red Jacket selected for crossing had a clear skin.
Appropriate crosses indicated that this mutant was y.  F2 segregations for dr
and bs are given below.<p>
<pre>

Black Queen x Wisconsin 55    
  + 62, dr 24                     
  + 76, bs 10                     
+ + 60, + dr 16, bs + 2, dr bs 8  

Black Queen x Red Jacket
  + 57, dr 22 
  + 60, bs 21
+ + 47, + dr 12, bs + 10, dr bs 10  
</pre>

These data indicate that dark red and black shoulder are determined by single
recessive genes which are loosely linked.  There was no indication of linkage
with u, c or y.<p>

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