4 The Journal 
the upper leaves. The lower leaves of 
plants possessing this character are 
normal, the striping first making its 
appearance on about the tenth leaf 
from the seed. From the tenth to the 
uppermost, the blades are marked with 
fine, narrow, nearly white stripes which 
are usually from 1/10to 1/4 mm. in 
width and vary from a few millimeters 
to many centimeters in length. In 
pronounced cases the stripes are sepa- 
rated by not more than their width. 
The general effect of the closely spaced 
fine stripes is to give the blade a grayish 
appearance that contrasts sharply with 
the uniform green of normal leaves. 
(See frontispiece.) 
Lineate plants first appeared, or at 
least were first observed, in four prog- 
enies of a hybrid sweet corn that was 
being grown at Lanham, Md., in 1918. 
The sweet corn in which the lineate 
plants occurred was a hybrid between 
Stowells’ Evergreen and a prolific variety 
of field corn from Brownsville, Tex.! 
The original cross was made in Texas 
in 1912. In 1913 the F, population 
was grown in an isolated block at 
Victoria, Tex. In 1914 an F: popula- 
tion was grown at Lanham, Md., and 
fromithe crossing of two plants the 
ear designated Ph124 was secured. 
Plants from Ph124 were grown in 
Chula Vista, Cal., in 1915, and again 
in Lanham, Md., in 1916 when one cross- 
pollinated ear, Phi24LI1, was secured. 
In 1917 seeds of Ph124 were again 
of Heredity 
planted at Lanham, together with seeds 
of Phi24L1. From these plantings 
there were secured 16 cross-pollinated 
ears of Ph124, 31 cross-pollinated 
ears of Ph 12411 and 8 crosses between 
Ph124 and Phi2411. 
In 1918 the 16 cross-pollinated ears 
of the Phi24 progeny and 3 of the 
crosses between Ph124 and Ph124L1 
were planted. Lineate plants occurred 
in 3 of the 16 progenies of Phi24 and 
in one of the crosses between Phi124 
and Phi24L1. The ratio of lineate 
to green plants is shown in Table I. 
The ratios are all reasonably close to 
the monohybrid 3:1, and the results may 
be explained by assuming that one par- 
ent of Phi24 was heterozygous for lin- 
eate, a simple Mendelian character re- 
cessive to the normal green. If the 
lineate character was the result of a 
mutation in a single gamete this mu- 
tation must have occurred in 1913 in 
one of the grandparents of Ph124. 
This follows from the fact that lineate 
plants have been confined to descend- 
ants of Ph124, that approximately one- 
fourth of the cross-pollinated progenies 
of Ph124 produced lineate plants (4 out 
of 19) and that in the progenies in 
which lineate appeared one-fourth of 
the plants exhibited this character. 
Six hand-pollinated ears were secured 
from the progenies shown in Table I. 
One of these six ears represented a 
cross between a normal green female 
plant and a lineate male, one was the 
result of crossing two lineate plants, a 
TABLE I.—Showing the Number of Lineate and the Number of Green Plants in Four Progenies Grown 
from Hand-Pollinated Ears. 
Progeny designation | No. of green plants 
LEAL AD Pen 5 cette cote ee Ole 15 
PRIA Se cen teal 20 
PADAT Sy ore srayertetacens ete tssane 18 
121 YAO eee Se Oe 24 
Motal a eAeh as. aoe fil 
No. of lineate plants Expected 3:1 
uf 16.5 Sn) 
11 23.3 theat/ 
6 18.0 6.0 
8 24.0 8.0 
32 82 27 
1 The history of this cross is discussed in ‘‘ Breeding Sweet Corn Resistant to the Corn Ear- 
worm,” Collins, G. N.,and Kempton, J.H., Journ. Agri. Res., XI, No. 11, pp. 449-572, December 
10, 1917. 
