Agronomy and Horticulture, Department of


Document Type


Date of this Version



Genetics 24 (1939), pp 368-384


Copyright 1939 R. A. Emerson


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.