Hayes and Garber - Cucurbit Breeding

190 BREEDING CROP PLANTS
pure race for the absence of these characters and a normal variety
all FI plants had normal leaves. In F 2 ,
ratios of 672 normalleaved
plants to 221 liguleless were obtained.
Chlorophyll Inheritance. Numerous abnormalities for chlorophyll
development have been observed in corn, many of which
behave as simple recessives giving a 3 1 ratio in the F : z of a cross
between the normal and abnormal form.
Lindstrom (1918) has reviewed earlier investigations of
chlorophyll inheritance and has made a careful genetic study
of several different chlorophyll abnormalities. Three of these
white, virescent-white, and yellow appear in the seedling stage.
The white form is a true albino, apparently lacking chloroplasts.
The virescent-white appears white at first, but under favorable
conditions it gradually becomes a yellowish green color, especially
at the tips of the leaves. There is considerable variation in the
appearance of different seedlings of this. type but genetically all
behave alike. The yellow type gives seedlings with a yellow
color. Both the white and the yellow seedlings die before
maturity.
The normal green form behaves as an allelomorph to the various
seedling abnormalities and contains the three dominant genes,
W, V, and L. Counts of the number of normal green plants
and the three seedling types obtained from various heterozygous
plants are as follows:
Green 1,513 White. 555
Green 4,297 Virescent-white 1,394
Green 1,493 Yellow 532
Virescent-whites which turned green on maturity were selfed
and produced a progeny consisting of 717 virescent-white seedlings
and nine green. The latter were due probably to stray
pollen.
From a study of interrelation of these various factors, Lindstrom
has concluded that the following phenotypic formulas explain
the appearance of different sorts of seedlings;
GREEN VIRESCENT-WHITE YELLOW WHITE
LVW LvW IvW LVw
IVW
Lvw
IVw
These studies have considerable bearing on the present
Ivw