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... more 10.000 glossed keywords and links to more than 100 figures and schemes, about 100 tables etc. can be obtained in addition to this limited INTERNET version either on CD-ROM or in modified design as book by CRC Press, Taylor & Francis Group, Boca Raton, USA

ear >>> spike

ear lifter (on a harvester): improves cutting efficiency with laid crops or overhanging ears agr

early generation test: selection schemes in which poor recombinants are discarded already in F2 and F3 generations meth

early selection: it is conducted on highly heterozygous individuals which become the parents of the next screening generation meth >>> late selection

earsh >>> stubble

ear-to-row planting >>> ear-to-row selection

ear-to-row selection: a separate growing of progenies (i.e., the separate sowing of lines or families); a procedure developed by the German breeder T. ROEMER (syn Ohio method) meth >>> Illinois method

echinate: having sharply pointed spines bot >>> prickly

ecological dominance: the state in plant communities in which one or more species, by their size, number, or coverage, exert considerable influence or control over the other species eco

ecological niche: the position occupied by a plant in its community with reference both to its utilization of its environment and its required associations with other organisms eco

ecology: the study of the interrelationships between individual organisms and between organisms and their environment eco

economic trait loci (ECL): sites in the genome that determine characteristics of economic importance gene

ecophene: the range of different phenotypes produced by one genotype within a certain environment eco

ecospecies: a locally adapted species; it shows minor changes of morphology and physiology to another species, which are related to a habitat and are genetically determined eco

ecosystem: the complex of an ecological community together with a biological component of the environment, which function together as a stable system eco

EcoTILLING: a high throughput, low cost technique for rapid discovery of polymorphisms in natural populations of plants; it is similar to TILLING but it differs from TILLING in that natural polymorphisms are detected rather than polymorphisms induced through chemical mutagenesis; on the other hand, single nucleotide polymorphisms (>>> SNPs), small insertions and deletions, and variations in microsatellite repeat number can be efficiently detected using the EcoTILLING technique meth biot >>> targeting-induced local lesions


ecotype: a locally adapted population of a widespread species; it shows minor changes of morphology and physiology that are related to a habitat and are genetically determined; the individuals of an ecotype are only uniform in regard to the traits that provide them with special adaptation to specific environments; all the other characters may vary; ecotypes may be found in perennial clover, alfalfa, grasses, or other forage crops eco

ecovalence: this parameter is a quantitative measure for the evaluation of ecological adaptability eco

Ecovar TM (ecological variety): a seed source of a plant species that can be licensed and that is the result of merging plant collections from a diversity of populations and environments within an ecozone with the objective of providing a diverse commercial seed source agr

ectoparasite: an external parasite phyt >>> opuntia

ectopic expression: expression of a gene out of its expected time or place gene biot

ectosite >>> ectoparasite

ectozoon >>> ectoparasite

edaphon: all (micro)organisms living in the soil close to the plant agr

eddish >>> stubble

edaphon: all (micro-)organisms living in the soil close to the plant agr

edging: a row of plants set along the border of a plot or flower bed agr meth

EDTA >>> ethylenediamine tetra acetic acid

eelworm: in cereals, there are two species of eelworm attacking plants, the cereal cyst nematode (Heterodera avenae), which can infest cereal crops, and the oat stem eelworm (Ditylenchus dipsaci), which attacks oats and rye, as well as several other crops and weeds phyt >>> nematode

effective breeding population (size): in general, the size of population, which is adjusted mathematically to permit comparisons with others; more specifically, it is the size of an equivalent ideal population, which is expected to experience the same increase in homozygosity over time (i.e., drift) as the population in question; the ideal population is one in which mating is at random in the absence of selection and in which all individuals have the same expected contribution to the next generation meth

effective seedling: any seedling that has survived in reasonable vigor for some arbitrary time and is so sited that it should make an effective contribution to the crop agr fore

efficiency of plating: number of plaques formed by a phage lysate; it can be different for different hosts biot

efflorescence: the time or state of flowering; in general, blooming or flowering bot >>> anthesis

egg: a female gamete or germ (egg) cell bot >>> Figure 25

egg apparatus: the structure containing the embryo sac, within which is the egg cell bot >>> Figure 25

egg cell >>> egg

egg mother cell: a megasporocyte from which an egg cell is derived during megasporogenesis bot

electrical conductivity test: tests are used specifically for certain crops (e.g. pea); this test measures the soluble salts, sugars and amino acids that leach into the soak water; the electrical properties of the soak water are measured by a conductivity meter (expressed as micro siemans); the higher the leachate, the lower the vigor; this test is particularly useful in detecting mechanical and frost damages of cells seed

electrical field fusion >>> cell fusion

electrofusion >>> cell fusion

electromorphs: allozymes that can be distinguished by electrophoresis phys chem

electron microscope: a microscope that permits magnification of particles up to 200,000 diameters; instead of having the specimen exposed to a light source, a stream of electrons is directed on the object; the higher resolving power of the electron microscope is largely the result of the shorter wavelength associated with electrons; the electrons are accelerated in a high vacuum through electromagnetic lenses and focused on the specimen; they are projected on a fluorescent screen where the image of the particle may be viewed or onto a photographic plate and/or film micr

electropermeabilization >>> electroporation

electrophoresis: the migration of charged particles under the influence of an electric field within a stationary liquid; the latter may be a normal solution or held upon a porous medium such as starch acrylamide gel or cellulose acetate meth

electroporation: the application of a short sharp electrical shock to protoplasts in order to force the incorporation or uptake of DNA by producing transient holes in the cellulose membrane biot

electrostatic separator: a machine that separates seed on the basis of their ability to accept and retain an electrical charge seed

elicitor: a molecule produced by the pathogen host (or pathogen) that induces a response by the pathogen (or host) phyt

elimination >>> culling

ELISA >>> enzyme-linked immunosorbent test

elite: high-grade seed used for both seed and ware production; or, an agronomically superior and high-performing local cultivar seed >>> base seed

elite germplasm: germplasm that is adapted (i.e., selectively bred and optimized to new environment); for example, maize, which is native to Mexico, has been adapted to many locations in the world gene seed

elite hybrid variety >>> elite

elite plants >>> elite

elite population: genetically advanced intensively managed population in a short term breeding program; sometimes used in same meaning as nucleus population meth

elite seed: the class of pedigreed seed corresponding to the foundation seed class in some countries seed >>> base seed

elite strains >>> elite

elite tree: a tree that has been shown by progeny testing to produce superior offspring meth hort fore

eluate: a liquid solution resulting from eluting prep

emasculate: to remove the anthers from a bud or flower before pollen is shed; a normal preliminary step in crossing to prevent self-pollination; there are basically two methods used for emasculation: individual emasculation and mass emasculation; mass emasculation is applied, for example, in monoecious maize by mechanical detasseling, in hemp by removing male plants from the dioecious population, in rice by spike treatment with high temperatures (warm water of about +42°C), in wheat by using gametocides, or in tobacco by dark-phase treatment during anthesis meth >>> Picture 10

emasculation >>> emasculate

EMBL3 vector: a replacement vector for the cloning of large (~20 kb) DNA fragments; it derives from phage lamda biot >>> lamda phage

embryo: the rudimentary plant within a seed that arises from the zygote, sometimes from an unfertilized egg cell, or from progressive differentiation in cell culture bot >>> Table 8

embryo culture: a method of inducing the artificial growth of embryos by excising the young embryos under septic conditions and placing them on suitable nutrient media; the method is often applied when postgamous incompatibility exists (e.g., in wide crosses) biot

embryogenesis: the formation of an embryo; after double fertilization, seed development begins with endosperm, embryo growth, and differentiation; during subsequent seed maturation the seed storage proteins, starch, and lipids accumulate before the seed undergoes desiccation and dormancy; during late embryogenesis endosperm and mature embryo express seed storage reserve genes; many other hydrophyllic proteins with certain function that share similar sequence repeats also are accumulated; they are called late embryogenesis-abundant proteins, protecting cells during seed desiccation (e.g., abscisic acid) bot >>> Table 8

embryogenic: related to or like an embryo bot

embryoid: an embryolike structure bot biot

embryonic leaves: initial leaves, which are easily discernible in the germ of a mature grain bot

embryo percent: the amount of embryo compared with endosperm and other seed parts, and/or the percent of embryo in the whole seed agr meth

embryo rescue >>> embryo culture

embryo sac: the female gametophyte is formed by the division of the haploid megaspore nucleus—the site of fertilization of the egg and development of the embryo bot >>> Figures 25, 28, 35

embryo sac development >>> embryo sac

embryo sac mother cell >>> embryo sac

emergence date: the time or date when plants start to emerge spikes, buds, flowers, or showing coleoptiles, first leaves, etc. agr meth

empty fruits: in seed production, a fruit without a seed, for example, it happens in the composite family (sunflower, chicory, lettuce, etc.); the so-called seed is a fruit (achene) of which the outer structures are comparable to the pod in the legumes; the true seed may or may not form inside the fruit, which is not (clearly) visible from outside seed

empty glume >>> spikelet glume

enantiomer: mirror image form of a molecule; there may be more than two, as several parts of the molecule may have a mirror image form chem phys

enation: an outgrowth from the surface of a leaf or other plant part bot

encapsidation (of viruses): the process when a virus forms the protein shell that surrounds the virus nucleic acid phyt

encapsulation: the process of enclosing fragile organic material in a protective casing, sometimes of a semisolid nature; it is used for planting or moving somatic embryos seed meth biot

3' end: describes the different, complementary ends of a DNA single strand; ends with an OH-group biot gene

5' end: describes the different, complementary ends of a DNA single strand; ends with a phosphate group biot gene

endangered species: a species on the verge of extinction eco

endemic: confined to a given geographic region; diseases continuously occurring in a particular area eco phyt

endemic species >>> endemic

end-filling: conversion of a sticky end (5' overhang only) to a blunt end by enzymatic synthesis of the complement to the single-stranded overhang biot

end-labeling: attaching a radioactive or nonradioactive label specifically to the ends of a DNA molecule biot

endocarp: inner layer of the fruit wall (pericarp); it may be hard and stony (peach pit), membranous (apple core), or fleshy (orange pulp) bot

endochimera >>> chimera >>> mutation >>> Figure 56 >>> Picture 001

endocytosis: the uptake of cellular material through the cell membrane by formation of a vacuole bot

endodermis: a specialized tissue in the roots and stems of vascular plants, composed of a single layer of modified parenchyma cells forming the inner boundary of the cortex bot

endoduplication: the doubling of the haploid chromosome complement owing to the failure of cell-wall formation cyto

endogamy: sexual reproduction in which the mating partners are more or less closely related bot >>> inbreeding >>> intrabreeding

endogenous rhythm: a type of rhythmic plant response or growth capacity that is not affected by external stimuli phys

endomitosis: a doubling of the chromosomes within a nucleus that does not divide, thus producing a polyploid; the doubling may be repeated a number of times, which leads to endopolyploidy cyto

endonuclease: any enzyme that cuts DNA at specific sites corresponding to specific base sequences within a polynucleotide chain; each endonuclease cuts at its own specific site; it is used to identify genomes, genotypes, and chromosomes, and it acts as a genetic marker chem phys

endophyte: (micro)organisms leaving inside host plants; seedborne, non-pathogenic, fungal endophytes are commonly found in symbiotic relationships with many members of the cool-season grass subfamily Pooideae; there are beneficial effects on plants possessing fungal endophytes, and detrimental effects on consumers of fungal endophyte-infected plants, e.g., fungi of the genus Neotyphodium were found in the diploid Triticum species (T. dichasians), a second endophyte, an Acremonium species, can be found in T. columnare , T. cylindricum, T. monococcum etc. phyt

endoplasm: the granular central material of the cytoplasm bot

endoplasmic reticulum: a system of minute tubules within the cytoplasm; two types are recognized, rough and smooth; these are particularly concerned with pathways of protein and steroid synthesis bot

endopolyploid: diploid individuals whose cells containing 4C, 8C, 16C, 32C, etc. amounts of DNA in their nuclei gene cyto >>> endomitosis >>> endoduplication

endoreduplication: chromosome reduplication in the interphase of the mitotic cell cycle gene cyto

endosperm: in grasses, the reserve food material in the caryopsis lying outside the embryo; it is a starchy tissue that is formed during grain development; it provides nourishment for the developing embryo and for the seedling after germination until it can establish itself; usually the endosperm is triploid and originates during the double fertilization when one of the two sperm nuclei is fused with the two polar nuclei bot >>> Tables 8, 16

endosperm texture: the tendency of, for example, wheat endosperm to fracture either along the outlines of the cells (hard) or across the cells in a more irregular way (soft); it can be assessed by “grinding time” or by inspection of the grain cross-section bot meth

endospory: a condition in which the gametophyte develops within the spore wall, rather than externally bot

endotoxin: a poison produced within a cell and released only when the cell disintegrates phys

engraft >>> ingraft

enhancer: a modifier gene that may enhance the action of another gene gene

enneaploid: a polyploid plant with nine chromosome sets cyto

entire leaf: a leaf margin that has no teeth (i.e., smooth) bot

entomologist: an insect specialist phyt

entomology: the branch of zoology dealing with insects phyt

entomophilous: insect-borne pollen; entomophilous pollen is usually characterized by a sticky, mainly liquid layer that fills in the interstices of the sculpted pollen wall, or exine, and is responsible for its adhesion to insect and other vectors; this liquid pollen coat, the tryphine, is also responsible for pollen adhesion to the stigmatic surface in many species bot >>> Table 35

enucleate (of cells): removing the nucleus from a cell cyto biot

environment: the sum of biotic and abiotic factors that surround and influence an organism eco

environmental mutagen: a substance that may act as a mutagen in the environment of an organism gene eco

environmental resistance: all characteristics that protect the reproduction of plants against negative influences of the environment eco

environmental variance (VE): that portion of the phenotypic variance caused by differences in the environments to which the individuals in a population have been exposed stat

enzyme: a molecule, wholly or largely protein, produced by a living cell that acts as a biological catalyst phys

enzyme-linked immunosorbent test (ELISA): a highly sensitive immuno assay based on enzyme reactions; usually two antibodies are used; the first antibody binds to an antigen and mutates itself toward the second antibody, the antiglobin; the antiglobin is linked to an enzyme (e.g., horseradish peroxidase); the enzyme activity has to be easily detected (e.g., by a staining reaction); the degree of enzyme reaction quantitatively shows how many antibodies of the first type (i.e., of the original antigen) is present meth

e.o.p. >>> efficiency of plating

ephemeral: short-lived, temporary bio

epiallele(s): alternative states of a gene that have an identical DNA sequence but differ in methylation or chromatin structure and, hence, level of expression gene

epiblast: the primordial outer layer of a young embryo bot

epicarp: the outermost layer of a pericarp, as the rind or peel of certain fruits bot

epicormic branching: branches which grow out of the main stem of a tree, arising from buds under the bark; epicormic branching may increase knottiness fore

epicotyl: the portion of the embryo or seedling above the cotyledons bot

epidemic: a rapid increase in disease over time and in a defined space phyt

epidemic potential: the biological capacity of a pathogen to cause disease in a particular environment phyt

epidemic rate: the amount of increase of disease in a plant population per unit of time phyt

epidemiology: the study of disease epidemics, with an effort to tracing down the cause phyt

epidermis: the outermost layer of cells; it protects them against drying, mechanical injury, or pathogens bot

epigeal: s eed germination in which the cotyledons are raised above the ground by elongation of the hypocotyl (e.g., bean) bot

epigeal germination: it characterizes a type of germination in which the cotyledons are raised above the ground by elongation of the hypocotyl bot

epigenesis: the concept that an organism develops by the new appearance of structure and functions, as opposed to the hypothesis that an organism develops by the unfolding and growth of entities already present in the egg at the beginning of development bio

epigenetic: reversible, nonhereditary variation that may be the result of changes in gene expression gene

epigenetic regulation: regulation of gene activity mediated by a reversible change in DNA modification or chromatin structure gene

epigenetics: the study of the mechanisms by which genes bring about their phenotypic effects gene

epigenotype >>> epimutation

epimutation: a heritable change in gene activity that is not due to a change in base sequence; generally applied to an abnormal change in gene activity (e.g., in a tumor or a cell culture); in development, normal changes in gene activity occur and these are often somatically inherited; such changes are not epimutations; the pattern of epimutations in an individual or in a cell is referred to as the epigenotype gene

epiphytic: growing on other plants for its physical support but not drawing nourishment from them bot eco

epiphytotic: an unarrested spread of a plant disease phyt

episome: a bacterial plasmid that can integrate reversibly with the bacterial chromosome and replicate it bot biot

episperm >>> seed coat

epistasis: the nonreciprocal interaction of nonallelic genes; the situation in which one gene makes the expression of another; more specifically, gene interaction in which one gene interferes with the phenotypic expression of another nonallelic gene so that the phenotype is determined effectively by the former; the latter is described as hypostatic gene >>> Tables 6, 20, 21

epistasy >>> epistasis

epistatic >>> epistasis

epistatic variance >>> variance >>> epistasis

epitope: a site on an antigen at which an antibody can bind, the molecular arrangement of the site determining the specific combining antibody chem sero

epitope mapping: methods used for studying the interactions of antibodies with specific regions of protein antigens; important applications of epitope mapping are found within the area of  immunochemistry meth chem phys

EPSP synthase: an enzyme in plants metabolic pathways that leads to aromatic amino acid production necessary for the development of proteins essential to plants growth phys biot

equational division: the division of each chromosome during the metaphase of mitosis or meiosis into two equal longitudinal halves (i.e., sister chromatids), which are distributed to the two cell pols, and then incorporated into separate daughter nuclei cyto

equational separation >>> equational division

equatorial plane: the plane between the two daughter nuclei of a dividing cell cyto

equatorial plate: an arrangement of the chromosomes in which they lie approximately in one plane, at the equator of the spindle; it is seen during metaphase of mitosis and meiosis cyto

equilateral: the type of panicle (e.g., in oats) in which the branches appear to spread equally on all sides bot

equireplicate (block design): a >>> block design is called equireplicate if each treatment occurs in the same number of plots, i.e., if the number of occurrences of a given treatment in each block is summed, the result is independent of the treatment chosen; if the block design is binary, then this condition is equivalent to regularity of the corresponding hypergraph, i.e., each point is in a constant number of blocks stat

eradicant: a chemical substance that destroys a pathogen at its source phyt

eradicate: to remove entirely; to pull up by the roots meth hort agr >>> disease eradication

eradication: control of plant disease by eliminating the pathogen after it is established or by eliminating the plants that carry the pathogen phyt agr >>> disease eradication

erect: upright bot

erectoides mutant: in cereals, a mutant form showing upright tillers and/or leaves gene

error variance: variance arising from unrecognized or uncontrolled factors in an experiment with which the variance of recognized factors is compared in tests of significance stat

ersh >>> stubble

escape: applied to a plant that has escaped from cultivation and naturalized more or less permanently eco; in plant pathology, the failure of inherently susceptible plants to become diseased, even though disease is prevalent phyt

Escherichia coli (E. coli): an aerobic bacterium; because of its rapid multiplication, it is extensively used in molecular genetics and genetic engineering biot

espalier: a trelliswork of various forms on which the branches of fruit trees, grapevine, etc. are extended horizontally, in fan or other shape, in a single plane in order to provide better air circulation and sun exposure for the plants hort meth

essential element: any chemical element which is essential to the normal growth and reproduction of a plant; there are 16 essential elements: boron (B), calcium (Ca), carbon (C), chlorine (Cl), copper (Cu), hydrogen (H), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), nitrogen (N), oxygen (O), phosphorus (P), potassium (K), sulfur (S) and zinc (Zn) phys >>> micronutrient >>> trace element

essential oils: the volatile, aromatic oils obtained by steam or hydrodistillation of botanicals; most of them are primarily composed of terpenes and their oxygenated derivatives; different parts of the plants can be used to obtain essential oils, including the flowers, leaves, seeds, roots, stems, bark, and wood; certain cold-pressed oils, such as the oils from various citrus peels, are also considered to be essential oils, but these are not to be confused with cold-pressed fixed or carrier oils, such as olive, grapeseed, and apricot kernel, which are nonvolatile oils composed mainly of fatty acid triglycerides chem phys

EST(s) >>> expressed sequence tags

establishment: the process of developing a crop to the stage at which the young plant may be considered established (i.e., safe from juvenile mortality and no longer in need of special protection) agr fore

establishment period: the time elapsing between the initiation of a new crop and its establishment agr

ester: a compound that is formed as the condensation product; water is removed, of an acid and an alcohol, while water is formed from the OH of the acid and H of the alcohol chem phys

esterase: a member of hydrolases that may catalyze esters; esterases were frequently used as biochemical markers in breeding experiments chem phys

estimate: a numerical value obtained from a statistical sample and assigned to a population parameter; the particular value yielded by an estimator in a given set of circumstances or the rule by which such particular values are calculated stat

 estimation:it is concerned with inference about the numerical value of unknown population values from incomplete data, such as a sample; if a single figure is calculated for each unknown parameter, the process is called point estimation; if an interval is calculated within which the parameter is likely, in some sense, to lie, the process is called interval estimation stat

estimation error: the amount by which an estimate differs from a true value; this error includes the error from all sources (e.g., sampling error and measurement error) stat

estivation: stagnating or otherwise nonfunctional during the summer period bot agr hort

étagère: a series of open shelves for growing and displaying plants or in vitro cultures hort biot meth

ethanoic acid >>> acetic acid

ethanol: a liquid solvent chem

ethene >>> ethylene

ether extract: fats, waxes, oils, etc., that are extracted with warm ether in chemical analysis prep meth

ethereal oil >>> essential oil

ethidium bromide (EB): fluorescent molecule that intercalates between base pairs of DNA and RNA chem biot

ethrel: the trade name for ethephon, which is 2-(chloro-ethyl)-phosphonic acid; it is an ethylene generator when applied to plant surfaces; ethylene has numerous physiological effects, such as inducing synchronous flowering and fruit ripening, which assists mechanical harvesting, etc.; ethrel is also used as male gametocide to induce random cross pollination for recurrent mass selection in autogamous cereals, such as wheat or barley phys

ethyl alcohol >>> ethanol

ethyl methane sulfonate (EMS): a chemical compound that acts as a mutagen in plants chem meth >>> mutagen

ethyl alcohol >>> ethanol

ethylene: a volatile plant hormone; synthesis is promoted by auxin or damage in seedlings, in shoot apex, and various organs; it is known as a ripening hormone; it stimulates flowering and fruit ripening; it inhibits elongation of stems, roots, and leaves chem phys

ethylenediamine tetra acetic acid: known as edetic acid or tetra acetic acid, this chelator is a synthetic amino acid having a molecular weight of 292.25 and a molecular formula of C10H16N2O8; it is used in a wide range of biochemical and chemical procedures chem biot

etiolation: a plant syndrome caused by suboptimal light, consisting of small, yellow leaves and abnormally long internodes phys meth

etiology: the study of causes of diseases phyt

E-type: in sugarbeet breeding the high-yielding (E = Ertrag = yield) varieties with average sugar content seed

euapogamy: a form of apomixis in which the sporophyte develops from a gametophyte without fertilization and formation of zygotes bot

EUCARPIA: European Association for Research on Plant Breeding >>> organizations

eucell: a eukaryotic cell showing a nucleus, nuclear envelopes, chromosomes, and nuclear divisions bot

eucentric: a chromosomal interchange by which the translocated segment does not change the relative position to the centromere cyto

euchromatin: chromatin that shows the staining behavior of the majority of the chromosome complement; it is uncoiled during interphase and condenses during mitosis, reaching a maximum density at metaphase cyto

euchromatization: the induced or spontaneous change of heterochromatin into euchromatin cyto

euchromosome: a chromosome showing the typical features of the standard complement of a given species cyto >>> autosome

eugenic: favorable to the genetic quality of a population, as opposed to dysgenic gene

euhaploid: a haploid genome showing no deviating number of chromosomes compared with the standard genome of the species cyto

eukaryon: the highly organized nucleus of a eukaryote bot

eukaryote: an organism whose cells have a distinct nucleus bot

eukaryotic >>> eukaryote

euploid: a cell and/or plant having any number of complete chromosome sets cyto

euploidy >>> euploid

eupycnotic: normally coiled and normally stainable chromosomes cyto

eusexual: showing regular alternation of karyogamy bot

eusom: a plant showing each member of the chromosome complement with the same copy number cyto

evaluation: the recording of those characters whose expression is often influenced by environmental factors meth

everbloomer: a plant that blooms continuously throughout the growing season, for example, busy lizzie (Impatiens walleriana) hort

evaluation: the recording of those characters whose expression is often influenced by environmental factors meth

even-aged forest: a forest in which all of the trees present are essentially the same age (e.g., within 10 to 20 years) fore >>> uneven-aged forest

everbloomer: a plant that blooms continuously throughout the growing season, for example, busy lizzie (Impatiens walleriana) hort

evolution: the process by which new species are formed from preexisting species over a period of time evol >>> Tables 12, 32, 49, 50

evolution pressure: the joint action of mutation, immigration, hybridization, and selection pressure evol

evolutionary >>> evolution

evolutionary breeding: breeding procedure in which the variety is developed from an unselected progeny of a cross or multiple crosses, that have undergone evolutionary changes meth

evolutionary divergence: the mode of evolutionary change whereby an ancestral population is split into different genotypic populations or phyletic lines evol

evolutionary genetics: it provides useful information for guiding gene mapping; e.g., understanding the phylogeny helps to manipulate horizontal gene transfer between microorganisms meth

evolutionary plasticity: the degree of genetic adaptability of a species or other taxa evol

exchange pairing: the type of pairing of homologous chromosomes that allows genetic crossing-over to take place cyto gene

excised embryo test: a quick method for evaluating the growth potential of a root-shoot axis that has been detached from the remainder of the seed seed meth

excision repair: the repair of DNA defects by excision of defective olignucleotides in one of the two DNA strands and the subsequent resynthesis of the excised nucleotide sequence, utilizing the complementary base pair code in the intact strand gene

exhauster >>> aspirator

exhaustion test: a type of vigor test that measures the ability of seeds to grow rapidly under rigidly controlled conditions of high temperatures, relative humidity, and moisture content in continuous darkness seed meth

exine: the outer, decay-resistant coat of a pollen grain or spore; it shows different characteristics on the surface, which allows taxonomic differentiation between genera and even species; there are several scanning electron microscopy studies made on crop plants, also for comparisons in crop plant evolution bot

exocarp: the pericarp or ovary wall of angiosperm fruits is composed of three different layers; the outer layer is the exocarp bot

exocytosis: the extrusion of cellular material from a cell, as opposed to endocytosis bot

exogamy: outbreeding; all forms of sexual reproduction in which the mating of unrelated and/or more distantly related partners is dominating bot

exon: the portion of a gene that is transcribed into mRNA and is translated into protein (i.e., a DNA sequence in the encoding part of a gene) gene

exonuclease: a DNase enzyme that digests DNA beginning at the ends of the strands (e.g., exonuclease III degrades dsDNA starting from the 3' end, lamda exonuclease degrades ssDNA and dsDNA) gene phys biot

exotic species: a species that is not native to a region agr hort

exotoxin: a poison excreted by a plant into the surrounding medium phys

experimental alteration of germplasm >>> mutation

experimental design: the planning of a process of data collection; also used to refer to the information necessary to describe the interrelationships within a set of data; it involves considerations, such as number of cases, sampling methods, identification of variables and their scale-types, identification of repeated measures, and replications stat

explant: an excised fragment of a tissue or an organ used to initiate an in vitro culture biot

explantation >>> explant

expressed sequence tags (ESTs): DNA sequences derived by sequencing an end of a random cDNA clone from a library of interest; usually, tens of thousands of such ESTs are generated as part of a given genome project; these ESTs provide a rapid way of identifying cDNAs of interest, based on their sequence “tag” biot




expression imbalance map (EIM): a visualization method for detecting mRNA expression imbalance regions, reflecting genomic losses and gains at a much higher resolution than conventional technologies such as comparative genomic hybridization; simple spatial mapping of the microarray expression profiles on chromosomal location provides little information about genomic structure, because mRNA expression levels do not completely reflect genomic copy number and some microarray probes would be of low quality meth biot cyto

expression mapping: creation of quantitative maps of protein expression from cell or tissue extracts, e.g., EST maps; the approach relies on 2D gel maps and image analysis, and opens up the possibility of studying cellular pathways and their perturbation by disease or other biological stimuli at the whole-proteome level meth biot

expression variegation: a type of variation in gene expression during development that causes streaks or patches of cells to have different phenotypes gene

expression vector: vector constructs with a promoter sequence showing a highly efficient transcription of an inserted gene; the cell shows a high concentration of the gene product (i.e., protein) biot

expressivity of a gene: the degree to which a particular genotype is expressed in the phenotype gene

ex situ: out of place or not in the original environment (e.g., seeds stored in a genebank) seed meth

ex situ conservation: a conservation method that entails the removal of seed, pollen, sperm, or individual organisms from their original habitat, keeping these resources of biodiversity alive outside of their natural environment; the storage of plant genetic resources as seeds in genebanks at subzero temperatures is the most widely applied method; approximately 90 % of more than 6 million accesssions stored ex situ worldwide are maintained as seeds; other methods include maintenance of whole plants in field genebanks, as tissue culture in in vitro genebanks, and immersion of tissue , embryo or seeds in liquid nitrogen, i.e. cryopreservation; the latter two methods are particularly used for conservation of vegetatively propagated  species and for species with recalcitrant seeds meth seed

extension: 5' and 3' extensions are ssDNA regions at the ends of dsDNA; sometimes they are called overhangs or sticky ends biot

extensive crop: a crop that has low production costs and profit margins; for example, soybeans, maize, and wheat are typical extensive crops in North America agr

extensograph: a standard equipment for evaluating dough extensibility of cereal flour; used for measuring the extensibility and resistance-to-extension of a wheat-flour dough; the machine records extension force against time until the point of dough rupture; it is an important quality parameter for biscuit making and thus a breeding target meth

exterminate >>> eradication

extine >>> exine

extrachromosomal: structures or processes outside the chromosomes gene

extrachromosomal element: all genetic elements that are not at all times part of a chromosome, for example, plasmids, phages, transposons, insertion sequences, plastid (mitochondrial and chloroplast) genomes gene

extrachromosomal inheritance: inheritance that is not controlled by chromosomal determinants but by cytoplasmic components gene

extra chromosome >>> B chromosome

extranuclear: structures and processes outside the nucleus gene

ex vito: describes plants or organs that are transplanted from culture to soil or to pots meth

eye: the center of a flower when it is a different color from the petals; the term is also used for an undeveloped bud on a tuber (e.g., potato), or for a cutting with a single bud bot hort

eye depth (in potato): common scaling: 1 = very deep; 3 = deep; 5 = medium; 7 = shallow; 9 = very shallow meth prep

eyepiece: the lens or combination of lenses in an optical instrument (e.g., microscope) through which the eye views the image formed by the objective lens or lenses micr

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