Hayes and Garber - Cucurbit Breeding

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BREEDING OF VEGETABLES 241
means of determining the genetic nature of any particularvariety
or strain.
Factors A, C, E, (Gc) and Li appear absolutely coupled and
may, therefore, be considered to be a single factor with several
separate expressions. This factor gives salmon-pink or rose color
to the flower, and to the leaf axil, and to the stem in the presence
of Z>; purple dotting on seed-coats in the presence of F and B,
with reddish dots when B is absent and F is present; yellowish
green to grayish brown seed-coat color, brown hilum; indent
peas in the presence of L 2 .
The results of examining many thousand F 2 generation progeny
indicate that factors A, B, (Fa), 7, (Le), G, and R are independently
inherited.
Four groups of linked factors were found.
to the factorial notation used by White, are:
These, according
GROUP PARTIALLY LINKED RATIO OF NON-CROSSOVERS
TO CROSSOVERS
1 (Bl)S 8:1
2
A(Lf) 7:1
3 R(Tl) 63:1
4 GO Undecided
BEANS
Some Classification Characters. The species
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of garden beans
most commonly grown are Phaseolus vulgaris and P. lunatus.
The former is divided, from the standpoint of use as food, into
snap and shell beans, although there is some overlapping in these
groups. Shell beans are sometimes used as snap beans and vice
versa. Time required to mature, habit of growth, whether climbing
or bush, and size of plant are characters always described by
commercial seedsmen. Length of bearing period is also an important
character. Commercial growers sometimes desire varieties
which may be harvested in a few pickings but for the home
and general gardener, a variety with a longer bearing period
is
Size and shape of pod, number of seeds per
usually preferred.
pod in the case of snap beans, quality and color of the pod,
are used in classification; with snap beans, stringless, fleshy,
fine-grained pods are most desirable. The ease with which dry
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For a discussion of the classification of garden beans and a description
of varieties see TRACY, W. W., American Varieties of Garden Beans, U. S.
D. A., B. P. I. Bull 109, 173 pages, 1907; JARVIS, C. D., American Varieties
of Beans, Cornell Agr. Exp. Sta. Bull. 260: 149-255: 1908.
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