Hayes and Garber - Cucurbit Breeding

BREEDING OF VEGETABLES 251
vegetables (Malte and Macoun, 1915).
in making planting plans.
This fact may be utilized
CULTIVATED VEGETABLES OF THE GENUS BRASSICA
Cabbage and several other vegetables such as cauliflower,
brussels sprouts, kohl-rabi, and rutabagas, belong to the genus
Brassica. Few inheritance studies have been made with this
Cabbage has received more attention from
group of vegetables.
a breeding standpoint than the others.
Inheritance. The evidence so far accumulated indicates
that cabbage belongs to the cross-fertilization obligatory group.
Price (1911-1912) and Jones and Oilman (1915) were not
able to produce self-fertilized seed under a bag. Tschermak
(1916) maintains that many of the kinds of vegetables belonging
to the cabbage group freely intercross when in close proximity
at blooming time. The above facts are fundamental and show
the method of breeding which must be used. They may also aid
in explaining some unusual inheritance results.
Price crossed varieties of crinkled-leaf and smooth-leaf cabbage,
obtaining dominance for crinkled leaf in FI with no segregation
of this character in F 2 ,i.e., all plants (419) had crinkled leaves.
With respect to size, shape, and solidity of heads, color of foliage,
and length and thickness of stem, considerable more variability
was obtained in F 2 than in FI. In a cross between a crinkledleaf
cabbage and a cauliflower, the thick, leathery leaf of the
latter was dominant in FI and was the only apparent leaf characteristic
in F 2 . Head cabbage crossed with headless produced
nothing but headed forms both in the FI and F% generations.
As to type of head, the cabbage or leafy form was found to be
dominant over the type of head of the cauliflower. In F 2 the
cabbage head form was maintained without apparent segregation.
Crosses between cabbage and brussels sprouts gave FI
and F 2 generations identical with respect to habit of growth, i.e.,
all were determinate. Axillary buds were more common in the
hybrids than in ordinary cabbage. The thick stem of kohlrabi
was found to be dominant in a kohl-rabi-cabbage cross
and a limited number of F 2 individuals showed no segregation
of this character.
Sutton (1908) crossed reciprocally kohl-rabi and Drumhead
cabbage, obtaining, in F 2 ,
3 non-kohl-rabi plants to 1 resembling