Glossary Plant Breeding

Self-Fertilization. Fusion of male and female gametes from the same individual.
Self-Fertility. Capability of producing seed upon self-fertilization.
Self-Incompatibility. Genetically controlled physiological hindrance to self-fruitfulness.
Self Pollination. The transfer of pollen grains from an anther of a flower to the stigma of
the same flower or of different flowers of the same plant or clone. Its genetic
consequence is the same if different plants with the same genetic make-up are crosspollinated
(e.g., cross pollinating members of a pure line, of a heterozygote, Aa, and
of a clone).
Self-sterile. Incapable to set seed due to failure either to produce functional gametes or to
complete fertilization after self-pollination.
Semiconservative Replication. The established model of DNA replication in which each
of the two parental strands acts as a template for the synthesis of a new strand so that
each daughter DNA molecule has one parental strand and one newly polymerised
strand.
Semigamy. An abnormal type of fertilisation in which a male gamete enters into the egg
cell but there is no karyogamy (no fusion of nuclei). Both sperm and egg nuclei divide
independently so that the embryo contains separate sectors of paternal and maternal
tissues. It can be utilised to produce haploids in cultivated cotton.
Semi-isolation. Incomplete isolation between two populations, allowing incidental gene
flow.
Semisterility. A condition in which plants are characterised by having reduced number of
viable gametes and hence reduced fertility. Plants heterozygotic for certain types of
chromosome aberrations (e.g., inversion/translocation heterozygotes) usually show
this condition. Nevertheless, plants show sterility for male gametes more frequently
than for female ones.
Sequence Tagged Site. A relatively small sequenced region of a cloned genomic
fragment that can be used by a computer to align the cloned fragment into a contig.
Sex. A complex developmental character that refers to the state of being male and female.
It can be the sum total of contrasting and complementary characteristics exhibited by
male and female (as in humans and other higher animals and a few higher plants), +
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