Hayes and Garber - Cucurbit Breeding

DEFINITIONS 295
Cross. Synonymous with hybrid.
Cross-fertilization. The union of the egg cell of an individual with the
sperm cell of a different individual whether the organisms belong to the same
or different genotypes.
Cross-over. A separation into different gametes, of determiners that
are usually coupled, and the association of determiners in the same gamete
which are generally in different gametes.
Detassel. To remove the tassel, as in maize.
Cryptomere. A factor or gene whose presence can not be inferred from
an inspection of the individual, but whose existence can be demonstrated
by means of suitable crosses.
Determiner. Synonymous with gene or with factor as applied in genetics.
Dominance. In Mendelian hybrids the capacity of a character which
is derived from only one of the two generating gametes to develop to an
extent nearly or quite equal to that exhibited by an individual which has
derived the same character from both of the generating gametes.
In the
absence of dominance the given character of the hybrid usually presents
a "blend" or intermediate condition between the two parents, but may
present new features not found in either parent.
Dominant. (1) A character which exhibits dominance, i.e., that one of
two contrasted parental characters which appears in the individuals of the
first hybrid generation to the exclusion of the alternative "recessive"
character. (2) An individual possessing a dominant character in contrast to
those individuals which lack that character which are called "recessives."
Ear. A large, dense or heavy spike or spikelike inflorescence as the ear of
maize. Popularly applied also to the spike-like panicle of such grasses
as wheat, barley, timothy and rye.
Emasculation. The act of removing the anthers from a flower.
Endosperm. The substance which surrounds the embryo in many seeds,
as the starchy part of a kernel of wheat or corn.
Factor. An independently inheritable element of the genotype whose
presence makes possible a specific reaction or the development of a particular
unit-character of the organism which possesses that genotype; a gene or
determiner.
Floret. A small flower, especially one of an inflorescence, as in grasses
and Composite.
Fi, F 2 ,
F? }
etc. 1st, 2nd, and 3rd, etc. generations following, a cross.
Gamete. A reproductive cell containing x number of chromosomes.
Gene. Synonymous with determiner or factor.
Genotype. The fundamental hereditary constitution or sum of all
the genes of an organism.
Glabrous. Smooth, especially without hairs.
Glume. One of the two empty chaffy bracts at the base of each spikelet
in grasses.
Grain.
Cereal seeds in bulk.
Group. In genetics a broad general term for a complex
of other
categories and not for a complex of any particular category.
Head. A dense, short cluster of sessile or nearly sessile flowers on a very
short axis or receptacle, as in red clover or sunflower.