IUBio

Asking for free advice...

Ed Coe ed at teosinte.agron.missouri.edu
Fri Dec 4 16:09:02 EST 1998


I'm forwarding this inquiry to the maize net in case others may have
information to offer.

 The variation sy1, scutellum yellow, was reported by Sprague in the 1930's
(Cornell thesis and MNL 12:2-3), "tissue yellow in recessive rather than
white."   The color is attributed to carotenoids, and it is conceivable that
this is the same as the dominant white cap = lemon endosperm factor on
chromosome 9L, Wc1 or Wc1-Wh, the standard or No. 2 yellow type having wc1
allele).  Although I have worked with Wc1 classification in the endosperm, I
don't recall ever taking notice of color in the scutellum.  The dominant white
endosperm factor occurs in some popcorns, flint corns, white inbreds, and even
some light yellow field corns.  Incorporation of Wc1 into sweet corns might
actually contribute to whiteness of the endosperm and the germ in any event,
because indications are that pearly-white corn may be contributed-to by Wc1.
Authentic stocks of sy1 (i.e., possibly wc1 in contrast to Wc1) are
unavailable, to test whether sy1 and wc1 are the same, but it must be admitted
that sy1 is treated by Sprague as exceptional or rare (from Blue Flour
variety, later found in Emerson's strains tracing to diverse crosses).  Mike
McMullen comments also that the oil content of the germ may be a factor in
yellowness.
Ed Coe

Subject: Asking for free advice...
    Date: Fri, 4 Dec 1998 11:02:04 -0800
   From: Dave.Fisher at svseeds.com (Dave Fisher)
      To: ed at teosinte.agron.missouri.edu

     Ed,

     I breed sweet corn for the Seminis Vegetable Seeds - Asgrow brand and
     have a problem I thought you might be able to solve.

     We have had canners of sweet corn occasionally complain that when they
     can some white corns the yellow germs give a poor appearance in the
     canned product.

     I think all the white corns have yellowish colored germs and the ones
     that are more noticeable are where the cut is such that the germs pop
     out of the kernels and are free floating in the brine - thus more
     noticeable.

     Still...

     Are you aware of genes that affect the color of the germ, and are
     there any that may provide a more white germ in a white hybrid?  I've
     looked through the most recent publication of "Mutants of Maize"
     without finding anything.  I thought you might be aware of genes or
     gene combination effects that could help with this problem.  (No
     albino lethals please.)

     Incidentally, congratulations on a great book in "Mutants of Maize".

     Thanks for the help.

     David Fisher




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