Allelism tests of these factors with Inr1 were done by crossing these separate lines to a homozygous Inr1-R line, and then crossing the resulting F1 by our W23 ACR line. One of the factors produced only colorless kernels in a population of thousands of kernels, indicating probable allelism. (There is always the remote possibility that the factor is not allelic to Inr1, but is instead extremely tightly linked to Inr1--these tests cannot rule out that possibility). The other factor produced ears segregating 3:1 for colorless to colored kernels in these crosses, indicating non-allelism with Inr1. We have given the second factor the temporary designation Inr*-JD until allelism with other known aleurone color factors can be ruled out. We are currently in the process of conducting linkage tests of Inr*-JD with a comprehensive set of wx1-marked A-A translocations.
We still do not have a precise explanation
as to why John Deere corn is green. The R1 allele that is present
in the John Deere line is apparently only weakly suppressed by the dominant
color inhibitors. Perhaps the weak suppression of aleurone color occurring
over the surface of yellow endosperm (John Deere is Y1 Y1) gives
a green appearance through the combination of the light purple and yellow.
Another possibility is the production of a unique anthocyanin pigment or
some other chemical alteration in the aleurone cells that gives rise to
a green color. Further analysis will need to be done in order to resolve
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