OAPGRC Glossary of Genetic Resources Terminology


AbioticRelated to physical and chemical factors of the environment such as water, temperature, and soil.
Abiotic stressOutside (non-living) factors which can cause harmful effects to plants, such as soil conditions, drought, extreme temperatures.
AccessionA distinct, uniquely identified sample of seeds, plants, or other germplasm materials that is maintained as an integral part of a germplasm collection.
AcclimatizationThe adaptation of a living organism (plant, animal or micro-organism) to a changed environment that subjects it to physiological stress. Acclimatization should not be confused with adaptation.
AccuracyA measure of how good or close a calculated estimate of an animal’s genetic value is compared to the true genetic value.
AcellularTissues or organisms that are not made up of separate cells but often have more than one nucleus.
AcquiredDeveloped in response to the environment, not inherited, such as a character trait (acquired characteristic) resulting from environmental effect(s). cf acclimatization.
Active collectionGermplasm accessions that are maintained under conditions of short- and medium-term storage for the purpose of study, distribution, or use.
AfforestationThe establishment of a forest or stand of trees in an area where the preceding vegetation or land use was not forest.
AffectedReferring to an individual who manifests symptoms of a particular condition
AgroecologyThe use of ecological concepts and principles to study, design, and manage agricultural systems. Agroecology seeks to evaluate the full effect of system inputs and outputs by integrating cultural and environmental factors into the analysis of food production systems and to use this knowledge to improve these systems, taking into account the needs of both the ecosystem as a whole and the people within it. [GBA]
AgroforestryA collective name for land-use systems and technologies where woody perennials (tree, shrubs, palms, bamboos, etc.) are deliberately used on the same land management unit as agricultural crops and/or animals, either in some form of spatial arrangement or temporal sequence. [GBA]
Agro-morphological descriptorsCharacters observed in the field, such as plant height, colour of grain, size of grain, etc.
AnadromousThe annual migratory behavior of adult fish -such as salmon and lamprey- from the ocean into freshwater rivers and lakes in order to spawn.
Animal genetic resources databankA databank that contains inventories of farm animal genetic resources and their immediate wild relatives, including any information that helps to characterize these resources.
Animal genome (gene) bankA planned and managed repository containing animal genetic resources. Repositories include the environment in which the genetic resource has developed, or is now normally found (in situ) or facilities elsewhere (ex situ – in vivo or in vitro). For in vitro, ex situ genome bank facilities, germplasm is stored in the form of one or more of the following: semen, ova, embryos and tissue samples.
Animal modelThis is a system for genetic evaluations that estimates breeding values of bulls and cows at the same time. The system uses production data on all known relatives in calculating a genetic evaluation
AnnualA plant that takes one year or less to complete its life cycle and produce seeds.
AntagonismAn interaction between two organisms (e.g. moulds or bacteria) in which the growth of one is inhibited by the other. Opposite: synergism.
Anther cultureThe culturing of the part of the stamen that bears the pollen grains (anther) or of a single pollen grain, as a method of producing haploids, homozygotes, or all-male plants.
AnthesisIn flowers, the dehiscence of anthers, when pollen is dispersed.
AntibioticA class of natural and synthetic compounds that inhibit the growth of, or kill some micro-organisms. Antibiotics are widely used medicinally to control bacterial pathogens, but resistance in bacteria to particular antibiotics is often rapidly acquired through mutation.
AntibodyA defence substance (protein) synthesized by the immune system of an animal organism in response to the presence of a foreign protein (antigen), which it then neutralizes. Plants are a significant source of substances with which to manufacture drugs having antibody characteristics.
ApomixesAsexual reproduction in plants through the formation of seeds without fertilization (agamospermy), or the formation of a new individual from a group of cells without the production of an embryo or seed (vegetable reproduction).
AquacultureBreeding and rearing fish, shellfish, etc., or growing plants for food in special ponds.
Artificial inseminationA breeding technique, most commonly used in domestic animals and sometimes in captive breeding of wild animals, in which semen is introduced into the female reproductive tract by artificial means.
Artificial inoculationIntroduction of certain substances, or pathogens, into or on plant tissues, or to the placement of microorganisms into culture media (for experimental or diagnostic purposes).
Artificial selectionSelective breeding, carried out by humans, to produce a desired evolutionary response.
AsepticSterile, free of contaminating organisms (bacteria, fungi, algae but not generally including viruses, and particularly not internal symbionts).
Asexual Reproductionnot involving meiosis or the union of gametes
Asexual propagationVegetative, somatic, non-sexual reproduction of a plant without fertilization.
Asexual reproductionReproduction that does not involve the formation and union of gametes from the different sexes or mating types. It occurs mainly in lower animals, micro-organisms and plants. In plants, asexual reproduction is by vegetative propagation (e.g. bulbs, tubers, corms) and by formation of spores.
Autopolyploid or autoploidAn organism whose somatic cells carry more than two sets of chromosomes, with all sets coming from parents of the same species.


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Bacillus thuringiensis (Bt)A natural enemy of insects which was isolated from dead silk worms. This bacterium kills insects with the help of a protein, the so-called Bt-toxin. More than 50 Bt-toxins have been detected, each with its own characteristics. [CUB]
BackcrossCrossing an individual with one of its parents or with the genetically equivalent organism. The offspring of such a cross are referred to as the backcross generation or backcross progeny.
Base collectionA comprehensive collection of germplasm accessions held for the purpose of long-term conservation; stocks from the base collection replenish exhausted or expired stocks in the active collection.
Base populationThe population of trees from which individuals are chosen to establish the breeding population for a tree improvement program. Generally, refers to a wild population within a breeding region.
Basic seedProduced from seed developed by the plant breeder and so managed that the original genetic identity and purity of a given variety is faithfully conserved. The production of basic seed is carefully supervised or used by the representatives of an agricultural experiment station. Basic seed is the starting point for obtaining certified seed, either directly or through registered seed.
BiennialA plant living for two years and fruiting only in the second.
BioassayThe determination of the activity or concentration of a chemical by its effect on the growth of an organism under experimental conditions.
BiocontrolPest control by biological means. Any process using deliberately introduced living organisms to restrain the growth and development of other organisms, such as the introduction of predatory insects to control an insect pest. Synonym: biological control
Biological control- Control of pests by using predators to eat them. - Pest control strategy making use of living natural enemies, antagonists or competitors and other self-replicating biotic entities. [FAO bis]
BiomassAll organic matter that derives from the photosynthetic conversion of solar energy.
BiometryThe application of statistical methods to the analysis of continuous variation in biological systems.
BiopesticideA compound that kills organisms by virtue of specific biological effects rather than as a broader chemical poison. Differ from biocontrol agents in being passive agents, whereas biocontrol agents actively seek the pest. The rationale behind replacing conventional pesticides with biopesticides is that the latter are more likely to be selective and biodegradable.
BiopiracyThe patenting of genetic stocks, and the subsequent privatization of genetic resources collections. The term implies a lack of consent on the part of the originator.
BioprocessAny process that uses complete living cells or their components (e.g. enzymes, chloroplasts) to effect desired physical or chemical changes.
BioremediationA process that uses living organisms to remove contaminants, pollutants or unwanted substances from soil or water. See: remediation, bio-accumulation, bio-augmentation.
BiosafetySafety aspects related to the application of biotechnologies and to the release into the environment of transgenic plants and other organisms particularly microorganisms that could negatively affect plant genetic resources, plant, animal or human health, or the environment. [BSWG/2/5: FAO Draft International Code of Conduct for Plant Biotechnology as it Affects the Conservation and Utilization of Plant Genetic Resources]
BiosphereThe life zone of the earth including the lower part of the atmosphere and the upper part of the lithosphere.
BiotaThe living organisms of a region.
BiotypeA population in which all individuals have an identical genotype.
BisexualContaining both male and female reproductive organs in a single flower (flowers).
Breed- A group of animals or plants related by descent from common ancestors and visibly similar in most characteristics. Taxonomically, a species can have numerous breeds. - Either a sub specific group of domestic livestock with definable and identifiable external characteristics that enable it to be separated by visual appraisal from other similarly defined groups within the same species or a group for which geographical and / or cultural separation from phenotypically similar groups has led to acceptance of its separate identity. [FAO]
Breeding lineA genetic group that has been selected and bred for their special combinations of traits.
Breeding seedSeed (or vegetative planting material) produced by the plant breeder or sponsoring institution from the original form and used to produce basic seed.
Breeding valueThe value of an individual as a (genetic) parent. The part of an individual's genotypic value that is due to independent and therefore transmittable gene effects.


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CallusThe initial tissue formed by the cellular division of explants. It is usually uniform, not having been differentiated into organized tissues.
Callus cultureA technique of plant tissue culture, usually on solidified medium and initiated by inoculation of small explants. Used as the basis for organogenic (shoot or root forming) cultures, cell cultures or proliferation of embryoids. Callus cultures can be indefinitely maintained through regular sub-culturing.
Candidate geneA gene whose deduced function (on the basis of DNA sequence) suggests that it may be involved in the genetic control of an aspect of phenotype.
CapThe structure found on the 5´ end of eukaryotic mRNA, and consisting of an inverted, methylated guanosine residue. See G cap, cap site.
Cap siteThe site on a DNA template where transcription begins. It corresponds to the nucleotide at the 5’ end of the RNA transcript which accepts the G cap.
Cell fusionA technique of fusing two cells from different species to create one hybrid cell for the purpose of combining some of the genetic characteristics of each original.
Centre of diversityThe regions where most of the major crop species were originally domesticated and developed. These regions may coincide with Centers of origin.
Centre of RegionWhere plant domestication must have taken place, or domestication where agriculture originated.
Centers of origin and diversityPlaces in the world where crops have the greatest genetic diversity in the form of traditional crop and varieties and/or wild relatives. Centers of diversity are typically, but not always, the same locations as the centers of origin or oldest cultivation of the crop. [BSWG/2/5: UNIDO BINAS Website: Biotechnology Library: Perils amidst the promise: glossary]
Certified seedThe progeny of basic seed, which is produced and used in such a way that it maintains a satisfactory level of purity and genetic identity. It has been approved and certified by an official agency for certification.
Characterization of animal genetic resourcesAll activities associated with the description of AnGR aimed at better knowledge of these resources and their state. Characterization by a country of its AnGR will incorporate development of necessary descriptors for use, identification of the country's sovereign AnGR; baseline and advanced surveying of these populations including their enumeration and visual description, their comparative genetic description in one or more production environments, their valuation, and ongoing monitoring of those AnGR at risk. [FAO]
Clonal propagationThe reproduction of plants through asexual means, such as cuttings, grafts, or tissue culture.
CloneA group of genetically identical individuals that result from asexual, vegetative multiplication; any plant that is propagated vegetatively and that is therefore a genetic duplicate of its parent.
CollectionA sample (for example, variety, strain, population) maintained at a genetic resources center for the purposes of conservation or use (an accession); a group of collected samples.
CommodityA type of plant, plant product or other regulated article being moved for trade or other purpose [FAO bis]
CommunityA group of ecologically related population of various species of organisms occurring in a particular place and time.
Community type(a) A plant or animal association. (b) A given characteristic plant or animal community that is distinguishable by the habitual presence of a dominant species or group of species. It usually finds expression in the existence of a plant community with a given floral composition.
CompetitionUse or defense of a resource by one individual that reduces the availability of the resource to other individuals.
Competitive exclusionThe extinction of one species by another species in the same area through competition.
ConservationThe conservation of plant genetic resources refers to the maintenance of populations in their natural habitat (in situ conservation) or to samples of these populations in germplasm banks (ex situ conservation). Conservation presumes that the materials are useful or potentially useful and seeks to maintain and manage them for both current and future benefits.
Conservation of biodiversityThe management of human interactions with genes, species, and ecosystems so as to provide the maximum benefit to the present generation while maintaining their potential to meet the needs and aspirations of future generations; encompasses elements of saving, studying, and using biodiversity. [WRI et al.]
Conservation of farm animal genetic resourcesRefers to all human activities including strategies, plans, policies and actions undertaken to ensure that the diversity of farm animal genetic resources is being maintained to contribute to food and agricultural production and productivity, now and in the future. [FAO]
Conservation valuesThe value to society of conserving environmental resources.
ContainmentApplication of phytosanitary [or other] measures in and around an infested area to prevent spread of a pest or a disease [FAO bis]
Coral bleachingA phenomenon occurring when corals under stress expel their mutualistic microscopic algae, called zooxanthellae. This results in a severe decrease or even total loss of photosynthetic pigments. Since most reef building corals have white calcium carbonate skeletons, the latter show through the corals' tissue, and the coral reef appears bleached. [JVG]
Core collectionConsists of a limited set of accessions, derived from an existing germplasm collection to represent the genetic spectrum in the whole collection.
Cross(a) An organism produced by mating parents of different genotypes. (b) To hybridize.
Cross-breedingThe breeding of distinct and genotypic types or forms in plants. This may entail the transfer of pollen from one individual to the stigma of another of different genotype. [CUB]
Cross-fertilizationThe fusion of an ovule with a sperm cell from two individuals that have different genotypes. (See also Allogamy.)
Cross-pollinationThe transfer of pollen from the stamen of a flower to the stigma of a flower of different genotype, but usually of the same species. [CUB]
CryobiologyStudy of the effects of extremely low temperatures on biological systems
CryopreservationMaintaining tissues or seeds for the purpose of longterm storage at ultralow temperatures, typically between ?150°C and ?196°C; produced by storage above or in liquid nitrogen.
Cryopreservation(a) The conservation of materials at very low temperatures (-196°C), usually in containers with liquid nitrogen. (b) Freezing of embryos, specific plant parts (e.g. gametes, buds, seeds, pollen) or any biological material.
Cryogenic storageThe preservation of seeds, semen, embryos, or micro-organisms at extremely low temperatures, below -130 °C; at these temperatures, water is absent, molecular kinetic energy is low, diffusion is virtually nil, and storage potential is expected to be extremely long. [GBA]
CultivarA race or variety of a plant that has been created, or selected intentionally, and maintained through cultivation.


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DatabaseAn organized collection of data that can be used for analysis.
DihybridThe result of a cross between parents that differ in two specified genes.
Diploid - Having two sets of genes and two sets of chromosomes - one from the female parent, one from the male parent. - Having a pair of homologous chromosomes with the exception of the sex chromosome, the total number of chromosomes being twice that of a gamete. [CUB]
DistributionTo supply adequate samples of genetic resource stocks to breeders and other users.
DNA bankStorage of DNA, which may or may not be the complete genome, but should always be accompanied by inventory information. (Note: at the present time, animals cannot be reestablished from DNA alone.) [FAO]
DNA fingerprint (a) The pattern of DNA fragments obtained in restriction analysis of certain highly variable repeated DNA sequences within the genome. Their number and arrangement are virtually unique to each individual and can be used to identify that individual. (b) The graphic representation of that pattern.
DNA library, DNA bank, gene bank, or genomic library(a) A bank whose holdings comprise genes or fragments of genes. (b) A collection of recombinant DNA molecules that carry insertions that represent an organism’s entire genome. (c) A collection of DNA fragments amplified in cloning vectors. The cloned fragments may come from genomic (chromosomal) DNA or from complementary DNA (cDNA).
DNA polymorphismAny variation in DNA sequence, like point mutations, insertions, deletions or variation in the number of repeated nucleotide units.
DNA sequenceThe order of sequence of the nitrogenous bases of the nucleotides that constitute DNA and which codes for all genetic information. When it is a codifier (exon), it defines the order of the amino acids that form the corresponding protein.
DocumentationWith reference to plant genetic resources, the procedure by which information (data) on germplasm is identified, acquired, classified, stored, handled, and disseminated.
DomainA specific region or amino acid sequence in a protein associated with a particular function or corresponding segment of DNA
Domestic animal diversity (DAD)The spectrum of genetic differences within each breed, and across all breeds within each domestic animal species, together with the species differences; all of which are available for the sustainable intensification of food and agriculture production. [FAO]
Domestic biodiversityThe genetic variation existing among the species, breeds, cultivars and individuals of animal, plant and microbial species that have been domesticated, often including their immediate wild relatives. [GBA]
Domesticated speciesSpecies in which the evolutionary process has been influenced by humans to meet their needs (syn.: cultivated species). [CBD]
Domestication The process by which plants, animals or microbes selected from the wild adapt to a special habitat created for them by humans.
Dormancy(a) The state of metabolic rest during which the seed is incapable of germinating because of its structural characteristics (embryo or seed coats) or the effect of external conditions (e.g., light, temperature, aeration, and moisture). (b) The quality of being latent. (c) The state in which a seed, bud, or reproductive structure of a plant is found at rest, inactive, quiescent, or dormant but which can initiate activity when the necessary conditions for activation occur.
Drafting groupsTo facilitate negotiations, the President or the Chair of a meeting may establish smaller drafting groups to meet separately and in private to prepare text. Observers may generally not attend.
DuplicateA germplasm sample that was mistakenly introduced into a collection as a different accession but which is genetically identical to others already in the collection.
Duplicate genesTwo or more pairs of genes that produce identical effects, whether together or separately.


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Ecological systemA system comprising living things and the physical environment where they live. The system is characterized by interdependent relationships
EcologyThe science that studies living things at their different levels of organization and their interrelationships among themselves and with the environment.
Ecosystem- A dynamic complex of plant, animal, fungal, and micro-organism communities and their associated non-living environment interacting as a functional unit; the organisms living in a given environment, such as a tropical forest, a coral reef or a lake, and the physical part of the environment that impinges on them. [GBA modified by JVG] - A complex of organisms and their environment, interacting as a defined ecological unit (natural or modified by human activity, e.g. agroecosystem), irrespective of political boundaries. [FAO bis] - A community of organisms in their physical environment.
Ecosystem diversity The diversity among biological communities and their physical settings, characterised by differences in species composition, physical structure, and function. It is the highest level of biological diversity.
Ecosystem rehabilitationThe recovery of specific ecosystem services in a degraded ecosystem or habitat.
Ecosystem restorationThe return of an ecosystem to its original community structure, natural complement of species, and natural functions
EcotourismTravel undertaken to witness sites or regions of unique natural or ecologic quality, or the provision of services to facilitate such travel. [GBA]"
Ecotype or Ecotypic VariationA genetically differentiated population distinguished from adjacent populations by sharp discontinuities in character expression. Ecotypic variation is a result of adaptive selection. Ecotypes may be geographic, climatic, elevational, or edaphic.
Effective population sizeThe equivalent number of parents if all contributed the same number of progeny to the next generation.
EliteAdvanced germplasm in a breeding or crop improvement programme. [CUB]
ElectrophoresisA method of separating large molecules (such as DNA fragments or proteins) from a mixture of similar molecules. An electric current is passed through a medium containing the mixture, and each kind of molecule travels through the medium at a different rate, depending on its electrical charge and size. Agarose and acrylamide gels are the media commonly used for electrophoresis of proteins and nucleic acids.
ElectroporationA process using high-voltage current to make cell membranes permeable to allow the introduction of new DNA; commonly used in recombinant DNA technology.
EmasculationThe elimination of anthers from a flower, either closed or open, before pollen is released.
EmbryoThat portion of the seed resulting from union of male and female gametes and developing into a mature plant.
EndangeredA term that applies to taxa (population, subspecies, species) in danger of extinction and for which survival is unlikely if the causal factors of loss continue.
Endangered breedA breed where the total number of breeding females is between 100 and 1,000 or the total number of breeding males is less than or equal to 20 and greater than five; or the overall population size is close to, but slightly above 100 and increasing and the percentage of pure-bred females is above 80 percent; or the overall population size is close to, but slightly above 1,000 and decreasing and the percentage of pure-bred females is below 80 percent. [FAO]
Endangered-maintained breedCategories where critical or endangered breeds are being maintained by an active public conservation programme or within a commercial or research facility. [FAO]
EndemicNative to and restricted to a specific geographic area.
Endosperm or albumenA triploid tissue that comes from the triple fusion of a spermatic nucleus with the two polar nuclei in the megagametophyte. In seeds of certain species, the endosperm persists as storage tissue for food reserves, which are used during the development of both the embryo and seedling during germination.
EnhancementThe process of improving a germplasm accession by breeding while retaining the important genetic contributions of the accession. This process may entail simple selection.
Environment The sum total of external influences acting on the life, development, and survival of an organism or group of organisms.
EradicationApplication of phytosanitary [and other] measures to eliminate a pest from an area [FAO bis]
EstablishmentPerpetuation, for the foreseeable future of a pest, or a biological agent, within an area after entry [FAO bis]
Ethical valuesStatements of ethical principle that inform the private and social valuation of biological resources. [GBA]
EvaluationThe assessment of plants in germplasm collection for potentially useful genetic traits, many of which may be environmentally
ExplorationThe search for materials in the field.
Ex SituA method of conservation in which components of biodiversity are conserved outside of the site, away from the natural habitat.
Ex situ conservationEx situ literally means out of the original place; hence, the conservation of plant genetic resources outside the areas where they had developed naturally (i.e., outside their natural habitats).
Exotic(1) Not native to a given area; either intentionally transplanted from another region or introduced accidentally. (2) In plant breeding, it refers to plants types that are from outside a breeding region or exhibit traits that are uncommon to the prevalent crop plant type. [CUB]
ExplantA segment of tissue or an organ obtained from a plant (e.g., leaf, root, anther, shoot, bud, embryo, and meristem) and used to initiate an in vitro culture.
ExtinctionThe death of any lineages of organisms. Extinction can be local, (when it is known as extirpation) in which one population of a given species vanishes while others survive elsewhere, or total, in which all its populations vanish. [GBA]


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Farmers' rightsRights arising from the past, present and future contributions of farmers in conserving, improving and making available plant or animal genetic resources, particularly those in centres of origin. [JVG]
FaunaAll of the animals found in a given area.
Flora(a) A group of plants with characteristics in common. (b) A set of plant species that is found in a given place. It is usually described in terms of a systematic or alphabetical list of all the plant taxa recorded in that place.
Food chainA line that can be established in an ecosystem among organisms that feed, one from another. An example of a food chain is plant ?butterfly ?house wren ?barn owl. The food chains are interconnected through common links, creating a food or trophic network.
Food securityThe capacity and facility of access by all people, over time, to a sufficient quantity of food that permits them to live active and healthy lives.
Folk varietyLocal varieties of cultivated plants developed by indigenous farmers in traditional agricultural systems. By modern standards, such varieties are often highly variable genetically.
FragmentationThe breaking up of extensive landscape features into disjunct, isolated, or semi-isolated patches as a result of land-use changes.


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GameteMature male or female reproductive cell (sperm or ovum) with a haploid set of chromosomes (23 for humans).
GametophyteThat phase of the plant life cycle that bears the gamete producing organs; the cells have n chromosomes. In angiosperms, the pollen grain is the male gametophyte and the embryo sac is the female gametophyte.
GenBankGenBank is the DNA sequence database sponsored by the US National Institutes of Health. GenBank is produced in collaboration with EMBL and DDBJ.
GeneThe fundamental physical and functional unit of heredity. A gene is an ordered sequence of nucleotides located in a particular position on a particular chromosome that encodes a specific functional product (i.e., a protein or RNA molecule).
Gene cloningThe process of synthesizing multiple copies of a particular DNA sequence using a bacteria cell or another organism as a host. The gene of interest is inserted into a selfreplicating DNA molecule (DNA vector, often a plasmid) and the resulting recombinant DNA molecule is amplified in an appropriate host cell. Used in genetic engineering.
Gene conservation; Genetic resources conservationThe conservation of species, populations, individuals or parts of individuals, by in situ or ex situ methods, to provide a diversity of genetic materials for present and future generations.
Gene expressionThe process by which a gene produces RNA and protein, and hence exerts its effects on the phenotype of an organism.
Gene flowThe exchange of genetic material between populations through the dispersion of gametes and zygotes.
Gene interactionModification of gene action by a non-allelic gene.
Gene mappingDetermination of the relative positions of genes on a DNA molecule (chromosome or plasmid) and of the distance, in linkage units or physical units, between them.
Gene nameOfficial name assigned to a gene. According to the Guidelines for Human Gene Nomenclature developed by the HUGO Gene Nomenclature Committee, it should be brief and describe the function of the gene.
Gene poolAll the genes within a population.
Gene predictionPredictions of possible genes made by a computer program based on how well a stretch of DNA sequence matches known gene sequences.
Gene Product The name of the protein or RNA product (and its function, if relevant) that is coded for by the gene.
Gene replacementThe incorporation of a transgene into a chromosome at its normal location by homologous recombination, thus replacing the copy of the gene originally present at the locus.
Gene sequencingThe process of elucidating the nucleotide sequence of a gene.
Gene splicingA stage in the processing of mRNA, occurring only in eukaryote cells, in which intervening sequences (introns) are removed from the primary RNA transcript (hnRNA), and the coding exons are joined together to form the mature mRNA molecule.
Gene therapyAn experimental procedure aimed at replacing, manipulating, or supplementing nonfunctional or misfunctioning genes with healthy genes.
Gene trackingFollowing the inheritance of a particular gene from generation to generation.
Gene transferIncorporation of new DNA into and organism's cells, usually by a vector such as a modified virus. Used in gene therapy.
Gene translocationThe movement of a gene from one chromosomal location to another.
GenecologyThe study of the genetics of the populations of plants in relation to the ecological niches they occupy; the study of adaptive properties of the populations in relation to their environments.
Genetic codeThe sequence of nucleotides, coded in triplets (codons) along the mRNA, that determines the sequence of amino acids in protein synthesis. A gene's DNA sequence can be used to predict the mRNA sequence, and the genetic code can in turn be used to predict the amino acid sequence.
Genetic CorrelationThe correlation between traits that is caused by genetic as opposed to environmental factors. A genetic correlation between two traits results if the same gene affects both traits (pleiotropy) or if genes that affect the two traits are in linkage disequilibrium.
Genetic Distance A measure of the genetic differences between two populations (or species) calculated on the basis of allelic frequencies in both populations.
Genetic driftA cumulative process involving the chance loss of some genes and the disproportional replication of others over successive generations in small populations, so that the frequencies of genes in the population is altered. The process can lead to a population that differs genetically and in appearance from the original population.
Genetic Equilibrium Condition in a group of interbreeding organisms in which the allele frequencies remain constant over time.
Genetic Erosion The loss of genetic diversity, that is, of genetic materials, including individual genes or combinations of genes (genetic complexes), genotypes, and species.
Genetic GainThe amount of increase in performance that is achieved through genetic selection after one generation of selection.
Genetic IdentityThe characteristic that should be maintained during conservation. This refers to the maintenance, as a set, of all the alleles of all the accession’s genes.
Genetic Instability Susceptibility of stored seeds to cumulative genetic changes (with age), resulting in the alteration of the initial genetic structure of the conserved sample.
Genetic Integration The insertion of a DNA sequence into another through recombination.
Genetic Mapping Determining the linear order of genes and/or DNA markers along a chromosome.
Genetic marker A DNA sequence used to “mark” or track a particular location (locus) on a particular chromosome.
Genetic MaterialAll material, whether of plant, animal, microbial, or other origin, that contains functional units of heredity.
Genetic Recombination(a) A combination of alleles from different parents that produce a recombinant individual. Such an organism or progeny may result from a crossing event or from an independent reorganization of different chromosomes during meiosis. (b) In genetics, the term refers to new combinations of sequences that result from the physical interaction of two DNA molecules. In vitro, the term refers to genetic re-arrangement among DNA fragments from different or noncontiguous origins. In vivo, this occurs between homologous copies of a single gene (chromosomal manipulation) or as a result of integrating a genetic element (transposon, prophage, or transgene) into the genome.
Genetic ResourcesAre actual or potentially useful characteristics of plants, animals and other organisms that are determined genetically.
Genetic StabilityThe maintenance of a certain degree of genetic balance in each individual of a population.
Genetic StocksAccessions that typically possess one or more special genetic traits that make them of interest for research.
Genetic UniformityThe condition in which individuals of a population present identical or very similar genetic structures, so that one may deduce that they will behave similarly and will have the same susceptibility in terms of biotic and abiotic stresses. This condition potentially endangers the persistence of such a population, a situation that is known as genetic vulnerability. Both situations are more likely to occur when the population has been genetically improved, and whose tendency is to give rise to genetically uniform populations, whether homozygous or heterozygous.
Genetic VariabilityThe degree of genetic variation existing in a population or species, as a consequence ofthe evolutionary processes to which it has been subjected. It is that set of differences present among individuals of a single species. Genetic variability is the basis on which plant breeders develop new varieties.
Genetic VariationThe heritable variation, derived from changes in genes, usually because of environmental factors.
Genetic VulnerabilityThe condition that results when a crop or a plant species is genetically and uniformly susceptible to a pest, pathogen, or environmental hazard.
Genetically Modified Organism (GMO)An organism that has been modified by the application of recombinant DNA technology.
GeneticsThe study of inheritance patterns of specific traits.
GenomeThe complete set of genes and non-coding sequences present in each cell of an organism, or the genes in a complete haploid set of chromosomes of a particular organism.
Genomic library A collection of clones made from a set of randomly generated overlapping DNA fragments that stores genetic information either from an entire genome, a single chromosome or specific genes in a cell.
Genotype(a) The genetic composition of an organism, that is, the total sum of its genes, both dominant and recessive. (b) A group of organisms with the same genetic composition. (c) The genetic constitution of one or more genes of an organism with respect to a particular hereditary trait or set of traits. (d) In plants, that set of hereditary factors that regulate the organism’s way of reacting to external stimuli.
Genotype by Environment InteractionA dependent relationship between genotypes and environments in which the difference in performance between two or more genotypes changes from one environment to another.
Genotypic RatioThe proportion of different genotypes of a given progeny.
GenusA somewhat arbitrary group of closely related species, where perceived relationship is typically based on physical resemblance.
Geographic VariationVariation among individuals and populations found in a tree species natural geographic range. The amount and nature of variation may vary with the species, the extent of its geographic distribution and ecological and climatic diversity of habitats that it occupies in its natural range. A large part of this variation may be genetic and may be further divided into clinal, ecotypic and unexplained classes.
Germ CellOne of two cells found in the pollen grain and which divides by mitosis into sperm cells. This division may occur before or after pollination.
Germplasm(a) The base material of heredity, that is, the structure that carries the total sum of hereditary characteristics of a species. The word ‘germplasm’ supposes that the structure is able to give rise to a new generation, transmitting its genetic characteristics. (b) The total genetic variability, represented by germ cells, available for a given population of organisms. (c) The potential hereditary materials of a species, considered collectively.
Germplasm bank or Gene Bank An entity constituted to conserve genetic resources. For plants, it is the most practical method of safeguarding genetic material, storing samples of landraces, breeding products, varieties not in use, and wild species.
Germplasm CollectionA collection of many different varieties, species, or subspecies representing a diverse collection of genotypes and, hence, genetic diversity.
Green RevolutionIncreased production from the introduction of high-yielding varieties of major grain crops that were also aided by the more intensive use of fertilizers and irrigation.
Growth InhibitorAny substance inhibiting the growth of an organism. The inhibitory effect can range from mild inhibition (growth retardation) to severe inhibition or death (toxic reaction). Two plant growth regulators that may act as inhibitors are ethylene and abscisic acid. The concentration of the inhibitor, the length of exposure to it, and the relative susceptibility of the organisms exposed to the inhibitor, are all important factors which determine the extent of the inhibitory effect.
Growth Rate Increase in mass per unit of time.
Growth RegulatorA synthetic or natural compound that at low concentrations elicits and controls growth responses in a manner similar to hormones.
Growth RetardantA chemical that selectively interferes with normal hormonal promotion of growth and other physiological processes, but without appreciable toxic effects.


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HabitatThe place or type of site where an organism naturally occurs.
HabituationThe phenomena that, after a number of sub-cultures, cells can grow, without the addition of specific factors, such as no longer needing exogenous growth regulators in the tissue culture medium. Such cells are autonomous.
HalophyteA plant that can tolerate a high concentration of salt in the growing medium.
HaploidA cell or organism with a single genome.
HaplotypeA way of denoting the collective genotype of a number of closely linked loci on a chromosome.
Herbarium specimensA collection of preserved plants or plant parts, mainly in a dried form. These specimens are often used as the reference material to define a plant taxon.
Heritability (h2)The relative importance of heredity in determining the phenotypic variance.  It measures the degree to which offspring resemble their parents in performance for a trait.
HeterozygosityThe presence of different alleles at one or more loci on homologous chromosomes.
Hybrid(a) The first generation of offspring of a cross between two individuals that differ in one or more genes. (b) The progeny of a cross between species of the same genus or distinct genera.
Hybrid Seed (a) Seed produced by crossing genetically dissimilar parents. (b) In plant breeding, used colloquially for seed produced by specific crosses of carefully selected pure lines, such that the F1 crop displays hybrid vigour. As the F1 crop is heterozygous, it does not breed true and so new seed must be purchased each season.
Hybrid Vigour; HeterosisThe extent to which the performance of a hybrid in one or more traits is better than the average performance of the two parental populations.
Hydroponics The growing of plants in aerated water containing all the essential mineral nutrients, with no soil. Also called soilless gardening or cultivation.
High-input production environmentA production environment where all rate-limiting inputs to animal production can be managed to ensure high levels of survival, reproduction and output. Output and production risks are constrained primarily by managerial decisions. (Source: FAO, 1999)


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In Situ ConservationOn-site conservation. It is the process of protecting an species in its natural habitat, either by protecting or cleaning up the habitat itself, or by defending the species from predator.
In Situ Conservation of Farm Animal Genetic DiversityIn AnGR: All measures to maintain live animal breeding populations, including those involved in active breeding programmes in the agro-ecosystem where they either developed or are now normally found, together with husbandry activities that are undertaken to ensure the continued contribution of these resources to sustainable food and agricultural production, now and in the future.
In Situ HybridizationUse of a DNA or RNA probe to detect the presence of the complementary DNA sequence in cloned bacterial or cultured eukaryotic cells.
In vitroStudies performed outside a living organism such as in a laboratory.
In Vitro Embryo Production (IVEP)The combination of ovum pickup (q.v.), in vitro maturation (q.v.) of ova, and in vitro fertilization (q.v.). A potential means of overcoming the variability between donors in number of ova collected in embryo-transfer programmes.
In Vitro Fertilization (IVF)A widely used technique in human and animal science, whereby the egg is fertilized with sperm outside the body. Usually, the fertilized egg is cultured outside the body for a few days (to confirm that fertilization has occurred) before re-implantation into a female.
In Vivo Studies carried out in living organisms.
Inbred lineThe product of inbreeding, i.e., the mating of individuals that have ancestors in common; in plants and laboratory animals, it refers to populations resulting from at least 6 generations of selfing or 20 generations of brother-sister mating, that are for all practical purposes, completely homozygous. In farm animals, the term is sometimes used to describe populations that have resulted from several generations of the mating of close relatives, without having reached complete homozygosity.
InbreedingThe mating of individuals that are more closely related than would occur under random mating.
Inbreeding DepressionA reduction in fitness and vigour of individuals as a result of increased homozygosity through inbreeding in a normally outbreeding population.
IncompatibilityIn plant reproduction, (a) The absence of fertilization and later seed formation. (b) The condition in which viable gametes cannot fuse because, for example, the stigma reduces or restricts the growth of the pollen tube; the formation of reproductive organs is not synchronized; or structural and/or functional barriers exist such as dichogamy, protandry, and protogyny. (c) The impossibility of achieving fertilization and seed formation through self-pollination, usually because of sluggish growth of the pollen tube in the style tissue.
IndigenousExisting and having originated naturally in a particular region or environment.
Intellectual property rightsThe rights to intangible property that is the product of the human intellect. Intellectual property may be protected by copyright, trademark or patent. The holder of intellectual property rights is usually the person or persons who developed the product or the organization that funded it.
IntrogressionA breeding strategy for transferring specific favourable alleles from a donor population to a recipient population. This would, for example, be of great interest for genes responsible for disease resistance genes, which could be introgressed into a susceptible but otherwise economically superior breed.
Invasive SpeciesAn introduced species which invades natural habitats.


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JuvenilityEarly phase of development in which an organism is juvenile and incapable of sexual reproduction.


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KaryotypeA photographic representation of the chromosomes of a single cell, cut and arranged in pairs based on their size and banding pattern according to a standard classification (http://www.ncbi.nlm.nih.gov/books/NBK5191/)
KernelThe nucleus of an ovule or of a seed, that is, the whole body within the coats. (A GLOSSARY OF PLANT GENETIC RESOURCES TERMS IN ENGLISH AND THEIR DEFINATIONS IN ENGLISH Compiled by Abebe Demissie EAPGREN JAN. 2005)
keystone speciesA species that plays a pivotal role in an ecosystem and upon which a large part of the community depends (Source: Reed F. Noss, Allen Y. Cooperrider (1994) Glossary of Conservation Terms. http://www.msu.edu/ ~jaroszjo/greenway/glossary/glossary.htm)


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Landraces(1) A population of plants, typically genetically heterogeneous, commonly developed in traditional agriculture from many years of farmer-directed selection, and which is specifically adapted to local conditions (2) landraces a crop cultivar or animal breed that evolved with and has been genetically improved by traditional agriculturalists, but has not been influenced by modern breeding practices
Large Offspring Syndrome (LOS)A morphologic syndrome presumably expressed at the molecular and physiological level due to some alterations in embryonic gene expression. Animal clones with LOS may experience difficulties in developing and maintaining the placenta. An LOS foetus is unusually large for its species, has longer than usual gestation periods, and often has immature lungs or heart abnormalities. Kidneys and liver may also be affected
Latent budAn inactive bud not held back by rest or dormant period, but which may start growth if stimulated
Lateral bud A bud produced at the base of a leaf petiole. See axillary bud (Glossary of biotechnology and genetic engineering FAO RESEARCH AND TECHNOLOGY PAPER 7 A. Zaid H.G. Hughes E. Porceddu F. Nicholas)
Lateral meristemA meristem giving rise to secondary plant tissues, such as the vascular and cork cambia. The term is sometimes used to refer to an axillary meristem
LeafIn plants, an expanded outgrowth of a stem, usually green, and the main photosynthetic organ of most plants
Legislation sui generis A particular form of protection of intellectual property, especially designed to cover certain criteria and needs
LegumeAny member of the pea or bean family (Leguminosae or alternately, Fabaceae), for example, beans, peanuts, and alfalfa
LemmaLemma in a grass spikelet, the lower bract of two that protect the floret
Library (gene library)A collection of cells, usually bacteria or yeast, that have been transformed with recombinant vectors carrying DNA inserts from a single species.
Life cycleThe complete sequence of events undergone by organisms of a particular.
Life form(a) The characteristic morphology of a mature organism. (b) According to the Raunkiaer system, the mechanisms by which plants survive the unfavourable season. Raunkiaer originally listed five types of life forms: phanerophytes, chamaephytes, hemicryptophytes, cryptophytes, and therophytes. His classification has since been broadened to include other mechanisms for plant survival under unfavourable conditions such as those used by, for example, epiphytes, succulents, halophytes, climbers, and hydrophytes"
Life sciences companiesCompanies which combine businesses in pharmaceutical, agricultural chemicals and products, and food and nutrition
LigninA major non-carbohydrate constituent of wood. It binds to cellulose fibres and strengthens and hardens cell walls
Line(a) a homozygous, pure breeding group of individuals phenotypically distinct from other members of the same species. Broader than strain. [CUB] (Glossary of terms related to the CBD) (b a group of individuals that descend from a common ancestor. Members of such a group are usually more closely related to each other than those of a variety.
Lineage (a) A group of individuals whose descent can be traced back to a single ancestor. (b) In evolution, a sequence of species, each of which is considered to have evolved from its predecessor.
LinebreedingA form of inbreeding which increases the average relationship of the individuals in a flock to an outstanding ancestor or line of ancestors.
Linkage The relationship that exists between two or more genes that tend to be inherited together because they are located on the same chromosome. This determines that combinations of these genes, like those of the parents in the gametes, are more frequent than their recombinations.
Linkage disequilibrium (Ld)Distribution of multilocus genotype combinations in a population for a given pair of markers that is incompatible with independent inheritance, thus indicating genetic linkage of the loci.
Linkage groupA group of genes distributed linearly in a chromosome.
Linkage mapAdiagram of a chromosome, indicating the position of genes.
LittoralThe ocean shore, including the rocky intertidal, sandy beaches, and salt marshes.
Living modified organisms (LMOs)(a) All organisms produced through the use of recombinant DNA technology, with a wider range of modifying technologies relevant when considering living modified prokaryotes and yeast. (b) genetically modified organisms (GMOs) whose genetic material does not occur naturally by mating or natural recombination.
LocusA distinct region of DNA (often a gene) in the genome.
LodiculeOne of two structures, similar to scales, at the base of an ovary of a grass flower.
Long-day plantPlant requiring short nights before flowering is initiated.
LongevityThe length of life. In seeds, it refers to the time that these remain alive. Longevity depends on the species and on the seeds’ storage conditions.
longitudinal dataData resulting from the observation of a population on a number of variables over time. Whenever observations are made more than once, the data is considered to be longitudinal
Low-input production environmentA production environment where one or more rate-limiting inputs impose continuous or variable severe pressure on livestock, resulting in low survival, reproductive rate or output. Output and production risks are exposed to major influences which may go beyond human management capacity. (Source: FAO, 1999)


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Male SterilityIn flowering plants, a condition whereby pollen is not produced or is sterile, or that part of the male organ that produces it does not function.
Marker GeneThat gene whose function and location are known and which expresses certain characteristics or very notable phenotypic differences that permit the analysis of its heredity, establish its presence in the genome, and detect recombination events.
Mass SelectionA form of artificial selection in which only individuals with phenotypic values greater or less than some threshold level is used for breeding.
Maternal Effect An effect attributable to some aspect of performance of the mother of the individual being evaluated.
Maternal InheritanceInheritance controlled by extrachromosomal (cytoplasmic) factors that are transmitted through the egg.
Medicinal and Aromatic Plant MaterialWhole plants and plant parts (including seeds and fruits) used primarily in perfumery and pharmacy. Includes fresh, dried, uncut, cut, crushed, and powdered material.
MetabolismIn an organism or a single cell, the biochemical process by which nutritive material is built up into living matter, or aids in building living matter, or by which complex substances and food are broken down into simple substances.
MicroarraySets of miniaturized chemical reaction areas that may also be used to test DNA or RNA fragments, antibodies, or proteins.
Micro-organisms(a) Groups of microscopic organisms, some of which cannot be detected without the aid of a light or electron microscope, including the viruses, the prokaryotes (bacteria and archaea), and eukaryotic life forms, such as (b) a micro-organism is a protozoean, fungus, bacterium, virus or other microscopic self-replicating biotic entity.protozoa, filamentous fungi, yeasts and micro-algae.
MitesFree-living and parasitic animals belonging to the order Acarina, class Arachnida (with spiders). Mites may infest plant crops, reducing their harvest. They may also infest plant tissue culture work areas and incubation facilities in search of sugars, and so contaminate culture vessels and spread bacteria and fungi.
Mutagen An agent that causes a permanent genetic change in a cell. Does not include changes occurring during normal genetic recombination.
MutationThe process by which a gene undergoes a structural change; a modified gene resulting from mutation.
MyceliumThreadlike filament making up the vegetative portion of thallus fungi.
MycorrhizaFungi that form an association with or have a symbiotic relationship with roots of more developed plants.


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Native A plant or animal indigenous to a particular locality.
Native RaceA population of usually heterozygous plants that were commonly developed in traditional agricultural systems through direct selection by farmers and which, characteristically, are adapted to local conditions.
Native SpeciesPlants, animals, fungi, and micro-organisms that occur naturally in a given area or region.
Natural CrossIn plants, a result of cross-fertilization, usually under natural conditions, where one parent of a plant’s genetic constitution is different to the other.
NematodesA class of slender, unsegmented worms, often parasitic. a.k.a. eelworms, especially when phytoparasitic.
NicheThe place occupied by a specie in its ecosystem and its role: where it lives, what it feeds on and when it performs all its activities.


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Observed heterozygosity The percentage of loci heterozygous per individual or the number of individuals heterozygous per locus.
Obsolete varietyPlant varieties that are no longer grown commercially; such varieties may be maintained in collections for use in breeding programs.
OctoploidCell or organism with eight sets of chromosomes, i.e., chromosome number 2n = 8x.
Oestrogen; estrogenThe generic term for a group of female sex hormones which control the development of sexual characteristics and control oestrus.
OffshootShort, usually horizontal, stem produced near the crown of a plant.
Offspring; progenyThe offspring of a particular tree or a particular combination of one female and one male tree.
Oilseed cropPrimarily brassica, soybeans, palm trees, peanuts, cottonseed and flaxseed used for the production of oils for cooking, protein meals and nonfood uses. Less common oil crops include sunflower, safflower, castor beans and sesame.
Oligonucleotide A molecule usually composed of 25 or fewer nucleotides; used as a DNA synthesis primer.
OntogenyLife cycle of a single organism; biological development of the individual.
OocyteThe egg mother cell; it undergoes two meiotic divisions (oogenesis) to form the egg cell. The primary oocyte is before completion of the first meiotic division; the secondary oocyte is after completion of the first meiotic division.
OogenesisThe formation and growth of the egg or ovum in an animal ovary.
Oogonium(a) A germ cell of the female animal, that gives rise to oocytes by mitotic division. (b)The female sex organ of algae and fungi.
OosphereThe non-motile female gamete in plants and some algae.
Oospore A resistant spore developing from a zygote, resulting from the fusion of heterogametes in certain algae and fungi.
Open nucleus schemesA nucleus breeding scheme in which the flow of germ plasm is bidirectional- from the nucleus to cooperating herds or flocks and from cooperating herds or flocks to the nucleus.
Open pollinationPollination by wind, insects or other natural mechanisms.
Organ A tissue or group of tissues that constitute a morphologically and functionally distinct part of an organism.
Organic speciesAn organism that exists in free state in an area but is not native to that area. Also refers to animals from outside the country in which they are held in captive or free ranging populations.
OrganismA biological entity able to reproduce itself or transfer genetic material. Microbiological entities are included within this concept, whether or not they are cellular. Almost all organisms are formed of cells, which may then be grouped into organs, and these into systems, each of which carries out particular functions.
Organism Classification line (EMBL)The OC (Organism Classification) lines contain the taxonomic classification of the source organism.
Organism Species line (EMBL)The OS (Organism Species) line specifies the preferred scientific name of the organism which was the source of the stored sequence.
Organism taxonomy Cross-Reference lineThe OX (Organism taxonomy Cross Reference) line is used to indicate the identifier to a specific organism in a taxonomic database.
Orthodox seedSeed that can be dried to low levels of moisture content and stored at low temperatures over long periods without losing viability.
OrthologsHomologous biological components (genes, proteins, structures) in different species that arose from a single component present in the common ancestor of the species; orthologs may or may not have a similar function. Compare with paralogs.
OrtseedsSeeds that contain any fluid fat-bodies in their seeds
Out of dangerA category of conservation status, describing a species or other taxon that had been included in a higher category on the continuum to extinction, but is now considered to be in a relatively safe state of conservation due to the adoption of effective conservation measures or elimination of previously existing threats. (See also Categories of species conservation.)
Outbreeding The crossing of genetically unrelated plants or animals; crossbreeding A system of mating in which parents are less closely related to each other than would be the case if mating occurred at random. It is the most common mode of sexual reproduction of forest trees.
OvaryIn flowers, the swollen base of the pistil, in which seeds are formed over-expression host.
OvuleIn plants, (a) the female gamete or germ cell. (b) The structure that contains the female gamete or mega gametophyte and becomes seed after fertilization.
OvumThe female reproductive cell which, after fertilization, becomes a zygote that develops into a new member of the same species. Also called an egg.


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Parapatric speciationSpeciation in which the new species forms from a population contiguous with the ancestral species' geographic range
PaleaIn a grass spikelet, the upper of two bracts that protect the floret. (See also Lemma.)
Parallel evolution The development of different organisms along similar evolutionary paths due to similar selection pressures acting on them paralogs: Homologous biological components within a single species that arose by gene duplication. Compare with orthologs.
ParasiteAn organism that consumes part of the tissues of its host, usually without killing the host.
ParasitismThe close association of two or more dissimilar organisms, where the association is harmful to at least one. cf commensalism; symbiosis parasitoid
Parataxonomist Field-trained biodiversity collection and inventory specialist recruited from local areas.
ParthenocarpyIn plants, the production of fruits without fertilization and normally without seeds.
Parthenogenesis (a) The development of an individual from a gamete without fertilization (b) Unisexual reproduction, where females give rise to offspring without being fertilized by males, for example, rotifers and certain crop pests such as aphids.
Partial dominance(a) The lack of complete dominance. (b) The production of an intermediate hybrid among reproducing types. (See also Incomplete dominance.)
Passport dataData that record the identity and provenance of a gene bank accession. They are composed of accession descriptors (e.g. accession number, s scien tific tific name, cultivar name) and collecting descriptors (e.g. collecting number, location of collection site).
PatentThe exclusive right granted to the ownership of an invention as a social counterpart to the innovation.
PathogenAn organism that causes a disease in another organism.
Pathway(a) A sequence of reactions undergone in a living organism. [CUB] (b) Any means that allows the entry or spread of a pest. [FAO bis]
PedigreeA record of parentage, sometimes also including data on the performance of parents and other relatives.
PenetranceThe degree to which a genotype is expressed as a phenotype; also used to characterize the likelihood that a gene will result in a disease.
PentaploidAn organism that has five sets of chromosomes, that is, with a chromosome number of 5n.
PerennialA plant that lives for 3 years or more. They may be woody such as shrubs and trees, or herbaceous. Herbaceous perennials may be evergreen; deciduous (i.e., the aerial organs are annual but the underground organs such as rhizomes and bulbs are persistent); or monocarpic, that is, living for many years until flowering and fruiting, after which they die, for example, Agave spp.
Perennial cropsIs a plant which last several years not perishing normally after once flowering and fruiting.
Perfect flowerA flower that has stamens and pistils.
Persistent Said of a plant organ that remains inserted or does not fall at maturity once it has fulfilled its physiological function Pests.
PhenologyThe study of timing of periodic phenomena such as flowering, growth initiation, growth cessation, etc. especially as related to seasonal changes in temperature, photoperiod, etc.
PhenotypeThe observable characteristics of an organism.
Phenotypic ratioThe proportion of different phenotypes of a given progeny.
PhotoperiodThe length of the day. Tropical maize, like other tropical plants, flowers on short days. When cropped in temperate areas, tropical maize will flower very late, around September, and will mature in winter. This is a genetic trait which does not exist in the varieties suitable for temperate areas. Such varieties are said to be insensitive to photoperiod.
PhotosynthesisChemical reactions in plants and plant-like organisms whereby the sun's energy is absorbed by the green pigment chlorophyll, permitting carbon dioxide and water to be synthesized into carbohydrates accompanied by the release of water and oxygen.
Phyletic evolution Genetic changes that occur within an evolutionary line.
PhylogeneticPertaining to the evolutionary history of a particular group of organisms.
PhylogenyThe study of timing of periodic phenomena such as flowering, growth initiation, growth cessation, etc. especially as related to seasonal changes in temperature, photoperiod, etc.
PhylumIn taxonomy and systematics, the highest level of classification below the kingdom. For instance, Mollusca (slugs, snails, clams, squids, etc.) constitute a phylum. [JVG]
Physiognomy That aspect of a plant community or species that is subject to visual appraisal. It depends on the set of special structures and characteristic forms of its biological constituents
Physiological raceThose pathogens of the same species and variety that are similar structurally, but differ in their physiological and pathological characteristics and, especially, in their ability to parasitize different varieties of a given host.
PhytomedicineMedicinal products based on standardized active ingredients within an herbal base. This term is sometimes used more broadly to include all plant-based medicines
PhytonutrientsNaturally-occurring compounds found in fruits and vegetables, such as beta carotene, capsaicin, and flavonoids.
Phytosanitary quality or plant health qualityThe set of characteristics that plant germplasm should have with respect to the presence or absence of pathogens transmissible in planting materials and/or micro-organisms that cause deterioration during conservation.
PicoplanktonPlanktonic organisms ranging in size from 0.2 to 2.0 micrometers.
PistilInflowers, the female organ where the seed originates. It comprises the ovary, style, and stigma Pistillate flower.
PlanktonFloating and drifting organisms that have limited swimming abilities and that are carried largely passively with water currents (opp. nekton). These include bacteria (bacterioplankton), plants and plant-like organisms (phytoplankton) and the animals (zooplankton) that eat them.
Plant breeders' linesUnreleased lines or parents of hybrids maintained by breeders as part of their working stocks. Breeders usually develop and carry many lines of which only a small number are ever released into commercial productionplant cell culture.
Plant community A more or less complex group of plants that occupy a certain area, regardless of the character, composition, and structure that the plants present.
Plant formation That group of plant communities, delimited in nature by particular physiognomic characters, depending on the dominant forms of life and the way in which space is occupied. A plant formation represents the expression of given living conditions and has, as its base, a particular type of environment.
Plant functional attributes Readily observable features of vegetation that are considered significant for growth, physiology and survival (for example pollination mechanisms, seed dispersal mechanisms, rooting systems.)
Plant genetic resources (PGR)These are the total of all the gene combinations produced during plant evolution. They range from wild species with agricultural potential to cloned genes. The term implies that the material has or may have economic or utilitarian value, whether current or future, perhaps the most important being that which contributes to food security. (See also Genetic resources.)
Plant cell cultureGrowth of plant cells or roots of plants in bioreactors.
PlantletA small rooted shoot developed from seed or from cultured cells either by embryogenesis or organogenesis.
Plasmagene The cytoplasmic unit of heredity
Polar nucleiThe two central nuclei found within the megasporangium and which join with the second sperm cell in triple fusion. In certain seeds, the product of this triple fusion gives rise to the endosperm.
Pole cells A group of cells in the posterior of Drosophila embryos that are precursors to the adult germ line.
Pollen A fine powder produced by anthers and male cones of seed plants, composed of pollen grains. Each grain encloses a developing male gamete, itself having originated from a microspore.
Pollen culture The in vitro culture and germination of pollen grains. Callus cultures thus obtained will form shoots or embryoids which develop into monoploid plants. See anther culture; microspore culture.
Pollen grainA microspore produced in the pollen sac of angiosperms or the microsporangium of gymnosperms. Unicellular, with variable shape and size, and usually ovoid from 25 to 250 µm.
Pollen tube A tube that, under favourable circumstances, develops from the pollen grain after being placed on the stigma of a flowering plant. It grows down the style to the ovary and eventually to an ovule. The sperm cell is carried to its destination in the tip of the pollen tube
Pollination The transfer of pollen from the anther to the stigma in flowering plants or from the male to the female cone in gymnosperms
PollinatorA pollinator is an agent, generally an animal (insect, bird, bat, etc.) that carries pollen to the female part of a flower.
PolycrossAn isolated group of plants or clones distributed so that random cross-pollination can occur.
PolymorphicIn the context of this report, plants with several to many variable phenotypic or genetic forms.
PolymorphismPresence in a given population of several forms, more precisely named alleles, of the same gene or haplotype. Polymorphism in nucleotide sequences has provided powerful diagnostic tools.
PolyploidyOrganism containing two or more sets of genes or chromosomes.
Population A group of individuals of a species living in the wild in a given area. It is the most significant level of organization of a species and is also of evolutionary and conservational significance.
Population density Number of cells or individuals per unit. The unit could be an area or volume of medium.
Population genetics The study of variation in genes among a group of individuals.
Population viability analysisA comprehensive analysis of the many environmental and demographic factors that affect survival of a population, usually small post-emergent.
Pre-breedingThe development of germplasm to a state where it is viable for breeder's use. Primarily involves the evaluation of traits from exotic material and their introduction into more cultivated backgrounds.
Precautionary principleA proactive method of dealing with the environment that places the burden of proof on those whose activities could harm the environment. (Opposite: wait-and-see principle)
Predator(a) An animal that kills and eats animals. (b) A natural enemy that preys and feeds on other animal organisms, more than one of which are killed during its lifetime [FAO bis]
PreservationStorage of materials in collections under conditions that promote long-term survival and the use of propagation methods that protect genetic integrity during regeneration.
Primary characterizationCharacterisation of plant or animal species, based on simple morphological characters (e.g. size, shape, colour). These characters must be useful in terms of immediate and easy identification by any breeder, and easy to record by simple observation of the species at different developmental stages.
Primary consumers or heterotrophs These organisms take advantage of the chemical energy stored in the organic matter of primary producers. This level is composed of herbivores.
Primary culture A culture started from cells, tissues or organs taken directly from organisms. A primary culture may be regarded as such until it is sub-cultured for the first time. It then becomes a cell line.
Primary forest A forest largely undisturbed by human activities. (Also: natural forest; opp. secondary forest.)
Primary gene pool For plants, a cultivated species and its wild relatives that are readily intercrossed so that gene transfer is relatively simple
Primary growth (a)Refers to apical meristem-derived growth; the tissues of a young plant.
Primary meristem Meristem of the shoot or root tip giving rise to the primary plant body.
Primary metabolites Compounds ubiquitous in living organisms and essential for life, such as carbohydrates, the essential amino acids and polymers derived from them.
Primary producers or autotrophs These take advantage of the energy from light, using photosynthesis. They are able to synthesize organic matter from inorganic matter. This level corresponds to that of green plants.
Primary production This represents the increase in biomass of the primary or photosynthetic producer organisms. Gross primary production refers to the biomass synthesized through the photosynthetic activity of primary producersprimary productivity.
Primary tissueA tissue that has differentiated from a primary meristem.
Primary valueThe value of the system characteristics upon which all ecosystem functions depend.
Prime center of diversityPlace where domestication first took place.
Primitive cultivarCrop forms developed from landraces. Improvement through selection restricted to a few specific characteristics and often more uniform in nature than a landrace.
Primitive varietyLocal varieties of cultivated plants developed by indigenous farmers in traditional agricultural systems. By modern standards, such varieties are often highly variable genetically.
ProchlorophyteBacteria that are the smallest photosynthetic cells (less than one micrometers; see picoplankton) in the open ocean; nearly ubiquitous in the sea.
Production environmentIn AnGR: All input-output relationships, over time, at a particular location. The relationships will include biological, climatic, economic, social, cultural and political factors, which combine to determine the productive potential of a particular livestock enterprise. (Source: FAO, 1999)
Production function This describes the outputs that may be obtained from combining different quantities of inputs.
Production traitsIn AnGR: Characteristics of animals, such as the quantity or quality of the milk, meat, fibre, eggs, draught, etc., they (or their progeny) produce, which contribute directly to the value of the animals for the farmer, and that are identifiable or measurable at the individual level. Production traits of farm animals ate generally quantitatively inherited, i.e., they are influenced by many genes whose expression in a particular animal also reflects environmental influences. (Source: FAO, 1999)
ProductivityThis is the relationship between production and biomass. In algae, for example, which reproduce daily, that is, they double their mass every 24 hours, productivity is 100%. In contrast, the average productivity in land plants does not reach 0.3%. For example, an almond tree forms almonds only once a year. Productivity = Production/Biomass.
Progeny An animal derived from sexual reproduction that has at least one cloned animal as a parent (but could result from two cloned animals mating).SCNT Acronym for Somatic Cell Nuclear Transfer. The process of generating a live organism asexually by transferring the diploid nucleus of a somatic cell from a donor animal to the enucleated embryo of a recipient animal.
Progeny testing A test used to help predict an individual's breeding values involving multiple matings of that individual and evaluation of its offspring.
Prokaryotes organismsAn organism having a cell without a distinct nucleus. Bacteria and blue-green algae are prokaryotes. (Opposite: eukaryote.)
ProliferationIncrease by frequent and repeated reproduction; growth by cell division.
Propagation The multiplication of plants by numerous types of vegetative material; an ancient practice dating from the dawn of agriculture, carried out in a nursery or directly in the field (vegetative propagation), and now in in vitro culture (micropropagation).
ProtandryThe condition of hermaphrodite plants where male gametophytes mature and are shed before female gametophytes are mature.
Protected area A legally established land or water area under either public or private ownership that is regulated and managed to achieve specific conservation objectives.
Protoplast A bacterial or plant cell for which the relatively rigid wall has been removed either chemically or enzymatically, leaving its cytoplasm enveloped by only a delicate peripheral membrane. Protoplasts are spherical and smaller than the elongate, angular shaped and often vacuolated cells from which they have been released.
Protoplast cultureThe isolation and culture of plant protoplasts by mechanical means or by enzymatic digestion of plant tissues or organs, or cultures derived from these. Protoplasts are utilized for selection or hybridization at the cellular level and for a variety of other purposes.
PrototrophAn organism such as a bacterium that will grow on a minimal medium.
ProtozoanA microscopic, single-cell organism.
Pure breedingAlso straight breeding. The mating of purebreds of the same breed.
Pure line(a) A genetically pure line where all its members are homozygous, having originated from the self-fertilization of a simple homozygous individual. (b) Genetically pure individuals (homozygotes) who originated from self-fertilization and whose offspring are equally homozygous and homogeneous.
PyramidingA strategy for developing long-lasting genetic resistance in a cultivar by combining two or more different genes that confer similar resistance into the same breeding line.


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Qualitative trait or discontinuous variationA trait whose observed variation is discontinuous, or which presents several states. It is usually controlled by one or a few genes, with little or no influence from the environment (e.g., yellow flower versus white flower).
Quantitative geneticsThe area of genetics concerned with the inheritance of continuously-varying traits. Most practical improvement programs involve the application of quantitative genetics.
Quantitative inheritanceInheritance of measurable traits (height, weight, colour intensity, etc.) that depend on the cumulative action of many genes.
Quantitative trait A trait that is determined by a series of independent genes that have cumulative effects.


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ResistanceThe genetically based ability of a host plant to reduce, or to prevent the development of a pathogen.
Recalcitrant seedSeed that cannot be dehydrated nor conserved at low temperatures without suffering damage. It can be stored for only few days or weeks under special treatment. Species that have recalcitrant seeds or do not produce seeds are usually conserved in field germplasm banks. In these areas, collections of live plants are kept, that is, the germplasm is conserved as a permanent live collection. (See also Orthodox seed.)
Recessive gene (a) That gene which needs a double ‘dose’ to be expressed. (b) A gene that does not manifest itself in the presence of a counterpart or dominant allele. (See also Dominant gene.)
Recombinant Inbred LineA population of fully homozygous individuals that is obtained by repeated selfing from an F1 hybrid, and that comprises ~50% of each parental genome in different combinations.
RecombinationThe formation of new gene combinations as a result of cross-fertilization between individuals that differ in their genotype.
Recurrent parent or donor parentIn plant improvement, in a back cross, that parent with which the hybrid material is again crossed.
Regeneration or rejuvenationWithin the context of germplasm banks, the cultivation of a sample of an accession (e.g., seed, clone, in vitro plant, or other propagule) to produce fresh, viable, and sufficient samples of plants from which sexual or asexual seeds with similar genetic constitution can be harvested, and which permits the preservation, in a better state, of the seed or propagule when stored Grow-out of a seed accession for the purpose of obtaining a fresh sample with high viability and adequate numbers of seeds.
Registered seed Progeny of basic seed or certified seed that is produced and used in such a way that it satisfactorily maintains its identity and genetic purity. It is approved and certified by an official certification agency.
Regressive form With reference to crops, a species related to the cultivated form, growing in the wild, but not used in agriculture. It usually shows characteristics of both the cultivated species and its wild relatives.


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SampleThe part of a population, which is actually observed. In normal scientific practice, we demand that it is selected in such a way as to avoid presenting a biased view of the population. If statistical inference is to be used, there must be a way of assigning known probabilities of selection to each sample. If the probabilities of different samples are all equal, for example, the method is called simple random sampling.
Secondary consumers, also heterotrophs These feed on the primary consumers. This level is composed of carnivores.
Secondary forestNatural forest growth after some major disturbance (e.g. logging, serious fire, or insect attack). (Opp.: primary forest.)
Secondary gene poolFor plants, all the biological species that can be crossed with a cultivated species, but where hybrids are usually sterile. Gene transfer is difficult but not impossible.
SeedDehydrated nor conserved at low temperatures without suffering damage. It can be stored for only few days or weeks under special treatment. Species that have recalcitrant seeds or do not produce seeds are usually conserved in field germplasm banks. In these areas, collections of live plants are kept, that is, the germplasm is conserved as a permanent live collection. (See also Orthodox seed.)
Seed bankA facility designed for the ex-situ conservation of individual plant samples through seed preservation and storage.
Seed orchardA stand of trees, usually several hundred to several thousand in number, established and managed primarily for early and abundant production of seed for deployment. Trees in the orchard are derived and propagated from selected parent trees by grafting or by seed.
Seed viabilityThe ability of a seed to germinate under appropriate conditions.
Selection unitThe minimum number of organisms or cells effective in the screening process.
Self-fertilizationThe process by which pollen of a given plant fertilizes the ovules of the same plant. Plants fertilized in this way are said to have been selfed. An analogous process occurs in some animals, such as nematodes and molluscs.
Self-incompatibilityIn plants, the inability of the pollen to fertilize ovules (female gametes) of the same plant.
Self-pollinationPollen of a plant is transferred to the female part of the same plant or another plant with the same genetic makeup. Opposite: cross-pollination.
Semi-sterilityA condition of only partial fertility in plant zygotes; usually associated with translocations.
Sibling speciesSpecies so similar to each other as to be difficult to distinguish by human observers.
SilvicultureThe science of cultivating forest crops (usually timber), based on a knowledge of forest tree characteristics Somaclonal variations.
Somaclonal variationsStructural, physiological or biochemical changes in a tissue, organ, or plant that arise during the process of in vitro culture.
Spaida and SpaignSigns individual animals to genetic clusters based on spatial autocorrelations.
SpawnThe eggs of certain aquatic organisms or the act of producing such eggs or egg masses.
Species A group of organisms capable of interbreeding freely with each other but not with members of other species. (Note by JVG: this is a simplified definition; species concept is much more complex.) a taxonomic rank below a genus, consisting of similar individuals capable of exchanging genes or interbreeding.
Species diversityThe number and variety of species found in a given area in a region.
Species richnessThe number of species within a region. (A term commonly used as a measure of species diversity, but technically only one aspect of diversity.)
Species selectionThe differential multiplication and extinction of species as a result of differences in certain traits possessed by the organisms belonging to the various species, and causing a spread of the favouring traits through the fauna or flora as a whole.
Specific(a) Related to species. (b) Also said of the characteristic effect on the cells or tissues of members of a given species or which interacts with them, for example, of infectious agents.
StabilityThe ability of a given assemblage of organisms to withstand disturbance without a major change in the number of species or individuals.
Straddling stockA population of organisms that travels between the exclusive economic zones of two or more countries, or between them and the high seas.
StrainIn microbiology, that set of viruses, bacteria, or fungi that have the same gene pool.
Strong sustainable development principleThe opportunity set for future generations can only be assured if the level of biodiversity they inherit is no less than that available to present generations.
SubcultureThe aseptic transfer of part of a plant in a collection to a fresh medium for renewal and strengthening.
SubspeciesGroupings or populations within a species that are distinguishable by morphological characteristics or, sometimes, by physiological or behavioral traits.
Sustainable use The use of components of biological diversity in a way and at a rate that does not lead to the long-term decline of biological diversity, thereby maintaining its potential to meet the needs and aspirations of present and future generations.
SymbiosisThe close relationship of two organisms in proximity, with one benefiting and the other either benefiting (mutualism), not being significantly affected (commensalism), or being harmed (parasitism).
Sympatric speciationSpeciation via populations with overlapping geographic ranges.
Systems biology A field that seeks to study the relationships and interactions between various parts of a biological system (metabolic pathways, organelles, cells, and organisms) and to integrate this information to understand how biological


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Taxon (pl. taxa)A taxonomic group (e.g., species, genus, or family) at any level within a classification system of living beings that are thought to have certain similarities and a given degree of evolutionary relatedness. Taxa are typically organized hierarchically from the largest categories (e.g., kingdom, division, or class) where the members are less related to the smallest (e.g., species, subspecies, or variety), where the members are closely related.
Temperate phage A phage (virus) that invades but may not destroy (lyse) the host (bacterial cell). However, it may subsequently enter the lytic cycle
Temperature-sensitive mutantAn organism that can grow at one temperature but not at another.
Tertiary gene poolFor plants, those species that can be crossed with a cultivated species only with difficulty and where gene transfer is usually only possible with radical techniques. Biotechnology has, at least in theory, greatly enlarged this pool because transformation (a radical technique) makes possible the introduction of DNA from any species
Test or Field TrialA research planting established in a scientific design to develop knowledge or information on the performance of genetic materials (species, provenances, seed sources or progeny) on traits or attributes (survival, growth, pest susceptibility, frost hardiness, wood quality, etc.) of interest
Threatened speciesReferring to a species that is likely to become endangered within the foreseeable future, throughout all or a significant portion of its range.
ToxinA compound produced by an organism and poisonous to plants or animals.
Transgenic plantA plant carrying a transgene. (b) That plant whose genome has been altered by in vitro manipulation.
Transplant: noun(a) A plant grown in a cold frame, greenhouse, tissue culture or indoors for later planting outdoors. (b) To dig up and move a plant to another location.


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Umbrella speciesSpecies whose occupancy area plants) or home range (animals) are large enough and whose habitat requirements are wide enough that, if they are given a sufficiently large area for their protection, will bring other species under that protection.
Utilization of farm animal genetic resourcesIn AnGR: The use and development of animal genetic resources for the production of food and agriculture


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VarietyA plant type within a cultivated species that is distinguishable by one or more characters. When reproduced from seeds or by asexual means (for example, cuttings) its distinguishing characters are retained. The term is generally considered to be synonymous with cultivar.
Value of genetic resourcesThe values we derive from plant genetic resources are generally associated with the different levels of organization and diversity that exist in nature, from ecosystems to species, populations, individuals and genes. In considering the conservation of plant genetic resources it is necessary to clearly specify objectives aimed at. This is of utmost importance, as it is possible to conserve an ecosystem and still lose specific species; and to conserve a species and lose genetically distinct populations, or genes which may be of value in adaptation and future improvement of the species (Wilcox, 1982).
Value of genetic variationThe value of genetic variation can be expressed as an ecological, economical or ethical value. In practice, however, it is difficult to determine whether a specific genetic variant of a species will be of future value. Hence, within species it is difficult to separate the “resource” from the rest of the variation and in reality it is impossible to distinguish between genetic resources and genetic variation.
VariantAn organism that is genetically different from the wild type organism. a.k.a. mutant.
VariegatedPlants having both green and albino tissues. This difference in colour may result from viral infection, nutritional deficiency, or may be under genetic or physiological control.
VarietyA naturally occurring subdivision of a species, with distinct morphological characters and given a Latin name according to the rules of the International Code of Nomenclature. A taxonomic variety is known by the first validly published name applied to it so that nomenclature tends to be stable. cf cultivar; pathovar.
Vector An animal (e.g. an insect) that carries and transmits pathogens.
Vegetation That spatial structure or mode of organization of the set of plant species found in a given place. It is usually described by examining stratification and coverage, alluding to the species present and the dominant forms of life.
Vernalization That treatment of plants with heat or cold to modify successive stages leading to maturity. For some species, vernalization can be achieved by exposing germinating seed at temperatures slightly above freezing point.
Viability The possibility of growth.
VirulenceThe degree of ability of an organism to cause disease. The relative infectiousness of a bacterium or virus, or its ability to overcome the resistance of the host metabolism.
Virulent phageVoucher specimens: collections of organisms that are maintained to provide permanent, physical documentation of species identifications and associated data resulting from inventories.


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Wild speciesThose groups of organisms that are regularly found in nature and have not been domesticated.
Wide crossingIn plant breeding this refers to the process of undertaking a cross where one parent is from outside the immediate genepool of the other, i.e. landrace or primitive line crossed with a modern cultivar.
Wild and weedy relativesFor plants, those species that share a common ancestry and Eco geographic area with a crop species but that have not been domesticated. Most crops have wild or weedy relatives that differ in their degree of relationship to the crop. The ease with which genes can be transferred from them to the crop varies.
Wild relativePlant or animal species that are taxonomically related to crop or livestock species and serve as potential sources for genes in breeding of new varieties of those crops or livestock.
Wild speciesOrganisms in or out of captivity that have not been subject to breeding to alter them from their native (wild) state.
Wild typeIn genetics, a species or organism that carries the normal form of a gene or genes, as opposed to a mutant.
WildlifeLiving non domesticated animals


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XeniaThe immediate effect of pollen on some characters of the endosperm.
XenogeneicRefers to organs, genetically engineered (“humanized”) to decrease the chance of rejection, that have been grown in an animal of another species for potential transplant to humans.
XerophyteA plant very resistant to drought, typically adapted to extremely dry environments.


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YeastA unicellular ascomycete fungus, commonly found as a contaminant in plant tissue culture.


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Zoo FISHFluorescent in situ hybridization technique, probing metaphase chromosomes of one species with DNA from another species. The technique allows inferences to be made regarding the evolutionary relationships between species. See: Fluorescence in situ hybridization.
ZoonosisA disease that is communicable from animals to humans.
ZooxanthellaeMicroscopic dinoflagellate algae that live mutualistically in the tissues of certain marine invertebrates, including reef-building corals and giant clams.
ZygoteFertilized ovum of animal or plant formed from the fusion of male and female gametes.