--Peter A. Peterson

In the second outcross yielding the genotype a-m Sh2/a sh2 and crossed by a sh2 the progenies included the following range of frequencies (%) of round colorless (non-mutable) (Sh2) kernels: 2, 4, 7, 13, 26, 50. Other progenies show a zero to 8% distribution. This could mean a range in the number of functional elements that activate the receptor allele of a-m877527.

To test this possibility, a reconstitution test of the colorless segregants crossed with plants derived from the shrunken segregants (a-o sh2 ± element) showed spotted kernels confirming the activation of the allele by a second element and thereby verifying two-element control of mutability of this allele among these progenies.

System relationship: Assorted tests confirm that this mutability is not under En or Mrh control. The number of Cy in these progenies parallels the frequencies of mutable kernels among the a testcross progenies. This is illustrated in the following cross.
 

bz-rcy no Cy x A/a-m	Colored F1 (88 1418)
88 1418-1 x bz-rcy	2% bz--no spots
88 1418-lt x a sh2	1.8% colorless - non spotted

The Cy relatedness of c-m877527 can be changed from putative to near confirmed.

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