Glossary Plant Breeding

or – (in case of physiological differences), donor or recipient (as in prokaryotes)
individuals or clones within the same species and their capacity to perform
amphimixis and genetic recombination through reproduction. The biological
divergence of sex may be inherent (that is, genetic/chromosomal) or impressed on it
by its environment.
Sex Cell. A gamete.
Sex Chromosome. A chromosome whose presence or absence is correlated with the sex
of the bearer owing to its role in the sex determination, for example, XX-XY system
in humans or WW-WZ system in birds.
Sex Controlled Traits. Hereditary traits that appear more frequently in one sex than in
the counterparts. For example, pattern baldness occurs more frequently in men than in
women. The gene is located in the autosomes. Its expression is influenced by the
specific hormone. Also called sex-influenced traits.
Sex Cycle. The alternation of karyogamy and meiosis in eukaryotes.
Sex Determination. Any process by which sex of an individual is established. The
mechanism or process may be chromosomal, genetic or environmental.
Sex Limited Traits. Traits that are limited to one sex only. However, genes conditioning
such traits are located on the autosomes of both sexes (e.g., genes influencing the
milk yield in dairy cattle).
Sex linkage. The location of a gene on a sex chromosome, for example, X-linkage.
Sex Linked Traits. Traits governed by the genes carried on the specific sex chromosome
(usually X-chromosome), colour blindness, for example.
Sex Mosaic. Gynander/gynandromorph.
Sex Ratio. The number of males per 1000 females at zygote formation (primary sex
ratio), at birth (secondary sex ratio), or at sexual maturity (tertiary sex ratio).
Sexual. Of all processes involving both meiosis and fertilization by means of which
sexual reproduction and genetic recombination are achieved.
Sexual Polyploidization (Mendiburu and Peloquin 1970s). A process of obtaining a
polyploid via fusion of unreduced female and male gametes. If the fusion occurs
between an unreduced gamete (2n) and a normal one, it is called unilateral sexual
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