" it m-1
the "A," state of a, .

The expression of linkage of Spm with the wx locus in
chromosome 9.

I. 8731B-2 x 8726-2

The fully pigmented kernels have no active Spm in the
endosperm. The colorless kernels with pigmented spots reaived
an active Spm from the ear parent. The apparent linkage of this
Spm with the wx locus is 9.5% (42 "crossovers" in a total of 459).
the linkage may be closer than these data suggest. Some
transpositions of Spm may have occurred in the ear parent before
the meiotic divisions. Meiotic segregation could then produce
a gamete carrying the Wx locus and Spm, the association not being
related to crossing over.

II. 8735E-1 tiller ear x 8726-2

The pericarp variegation is an expression of the Ay" state
of an. Anthocyanin pigment is absent in those pericarp cells
that have an active Spm. It is produced in those cells having
no active Spm, and the intensity resembles ae given by the
standard Ay locus. (Bigment intensity. is always greater on the
sides of the kernel than on the top. See photo. of self-pollinated
ear of plant 8735E-1.)

Linkage of Spm to the wx locus is close, the apparent crossovers

being 11 in a total of 253 kernels or 4.3%.

III. 8735E-5 self-pollinated. This photograph shows the
phenotypes of kernels that appeared on the self-pollinated ear
of a plant having one active Spm,linked to the wx locus. Among
the 245 kernels on this ear, the following is evident:

(1) Normal ratio of Wx : wx = 181 Wx : 64 wx (M= 61%)

(2) One Spm in parent: Ratio of "No Spm" (fully pigmented
kernels) to kernels with active Spm (colorless kernels
with pigmented spots) is 66 : 179. Ter Oy yn Mey

(3) Linkage of Spm with wx is expressed:

117 in the Wx class to 62 in the wx class.

(4) This linkage is also shown in the relation between the
phenotype and the dose of Spm in the kernel. the higher the dose
of Spm, the fewer and smaller the pigmented spots. The
majority of kernels with only a few specks of pigment as in the
wx class. Kernels with many pigmented spots, some of which are
large are present in both classes but mainly in the Wx class.