Hayes and Garber - Cucurbit Breeding

MAIZE BREEDING 191
conception of inbreeding and cross-breeding as applied to corn
improvement. Lindstrom found, for example, that plants containing
the wW combination were less vigorous than WW
forms. As a rule, a Ww plant produced only a single stalk which
was easily blown over in a strong wind.
There are also abnormal chlorophyll types which appear in
the mature plant. Of these, golden, green-striped, fine-striped,
and japonica types are simple Mendelian recessives to normal
green. In the golden type, when a month or more old, the green
color begins to disappear. The golden type is not very vigorous
toward maturity. It produces abundant pollen and small ears.
The green-striped form appears about two months after germination.
These stripes are uniform in distribution, green and lighter
areas alternating, and running parallel through the leaf. Mature
green striped plants are less vigorous than normal green forms and
the leaves wilt more severely on hot days. The japonica types are
striped with green, pale yellow, yellow, and white, and are well
known, being frequently used for ornamental planting. These
forms are more vigorous than the golden or green-striped types.
There are also fine-striped and spotted forms. The spotted
forms have not as yet been studied thoroughly.
Four of the mature plant chlorophyll types have been found
to be recessive to the^ normal green forms. The following
genetic factors have been used by Lindstrom:
g
st
golden type
green-striped
j -r- japonica
/ fine-striped
The following summary expresses the factorial condition of
these forms of chlorophyll abnormality;
CHLOROPHYLL TYPES
CHLOROPHYLL, FACTORS
Green WVLGStJF or WVIGSUF
White
wVLGStJF
Virescent-white
WvLGStJF
Yellow
WvlGSUF
Golden
WVLgStJF or WVlgStJF
Green-striped
WVLGstJF
Japonica white-striped
WVLGStJF
Japonica yellow-striped
WVlGStjF
Fine-striped
WVLGStJf