Date of this Version
Genetics 24 (1939), pp 368-384
A Bolivian maize
maize with mosaic red pericarp and cob, here designated by the symbol M-M, crossed with a local inbred strain of maize having white pericarp and cob, W-W, produced in F1 21 M-M and 28
W-W plants, not far from the I : I relation expected on the assumption that
the M-M parent was heterozygous for pericarp and cob color, M-M/W-W.
In F2 and segregating F3 cultures, however, there were 130 M-M and 64
W-W plants obviously a 2 : I instead of the 3 : I relation expected. Later cultures
increased these records to 747 M-M and 382 W-W plants, a deviation
of only 6 k 10.5 from a 2: I ratio. Of 18 M-M plants tested, all were heterozygous
for pericarp color, though one-third were expected to be homozygous.
The odds against the chance occurrence of this deviation of 6 ± 1.3
are over 500 : I. This suggested that the 2 : I ratio might be brought about
by the elimination of homozygous M-M plants.