Glossary Plant Breeding

selection pressure results in at least partial restoration of the original genetic
composition.
Genic Hybrid Sterility. Failure to gamete formation in the hybrid due to abnormal
developmental processes caused by specific gene complexes. In this case, meiotic
pairing is completely normal; sterility seems to be caused by incompatibility between
genes derived from two parents.
Genocopy. The production of the same phenotype by different genes.
Genospecies. A genetically defined species; a group of individuals potentially able to
contribute to or share in a common gene pool.
Genotype. The genetic constitution of an organism as distinguished from its appearance
(phenotype). It is the specific allelic composition of an individual or of a cell, which
may be of the entire cell or, more commonly, of a certain gene or a set of genes. It is
stable (except for rare changes called mutations) compared to the phenotype, which
changes with time.
Genetics (Bateson 1905). The study of heredity and variation. The term has been derived
from a Greek word, which means, “to generate”. It is the study of genes through their
variation.
Genotypic. Of or concerned with genotype.
Genotypic Frequency. The frequency at which a genotype occurs in a population.
GISH. Genomic In Situ Hybridisation; a technique that may provide a clue to the
structure and evolution of alloploid species and genome origins. It can also be used
for monitoring introgression of genes and detection of chromosomal aberrations, not
possible by other approaches.
GP4. Genetic resources that contain specific useful gene(s) from different types of
organisms across texa that can be transferred through rDNA technology. Such a gene
pool may be called a gene ocean.
Germ Cell. Any of the reproductive cells in multicellular organisms. It covers both
ancestral forms and their ultimate differentiated products.
Germ Line. The cell lineage from which the gametes are derived in a multi-tissued
eukaryote.
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