Hayes and Garber - Cucurbit Breeding

CLASSIFICATION AND INHERITANCE OF SMALL GRAINS 97
factorily explain the results. Nilsson-Ehle obtained transgressive
segregation in F 2 in a cross between medium early and
late maturing varieties. Progeny from 112 F 2 plants were grown
in F 3 . Of these 112 plants, 98 gave segregating progeny for
maturity and 14 seemed to be homozygous. Homozygous
forms were obtained which were earlier than the early parent
and others which were later than the late parent.
Linkage of Characters. Association of numerous characters
in inheritance has been mentioned in the discussion of crosses
between the wild A. fatua and cultivated varieties of A. sativa.
Aside from the general characters mentioned, linkage has been
found between the factor for black color of the lemma and one
of the factors for pubescence.
In crosses between Burt, A. sterilis, and Sixty Day, A. sativa,
Fraser (1919) has found that the factors for the articulated base
of the lower grain, the awned condition, and the production of
medium basal hairs were linked in inheritance.
In the following
diagram A represents the factor for awning, B for Burt base, and
C a factor for the production of medium basal hairs.
4.14 5.00
F 3 .
A B C
The percentages of cross-overs were determined for F 2 and
As has been pointed out, each of the characters depends on a
single factor for its development. Five per cent, of cross-overs
occurred between the factors for awning and basal hairs; 4.14
per cent, between awning and the factor for Burt base, and 1.79
per cent, between Burt base and basal hairs.
False Wild Oats. False wild oats differ from the cultivated
varieties in the production of heavier awns, in heavy pubescence,
and in the basal articulation. False wild oats resembling cultivated
varieties in color and panicle characters have been found
by numerous investigators. Nilsson-Ehle (191 la) has reported
false wild oats in eleven pure-line selections and in two commercial
varieties belonging either to A. sativa or A. sativa orientalis.
A heterozygous false wild form was found in the second generation
of a cross between sativa varieties. It gave a ratio of 1
cultivated, 2 heterozygous to 1 false wild form. The heterozy-