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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

objective: the lens or combination of lenses that first receives the rays from an observed object, forming its image in an optical device, as a microscope micr

objective lens: the lower lens in a microscope that is closest to what is being looked at micr

obligate: restricted to a particular way of life phyt

obligate apomixis: seed apomixis with maternal offspring to 100 % bot

obligate parasite: an organism that cannot live in the absence of its host phyt

observation: a data collection strategy in which the activities of subjects are visually examined; the observer attempts to keep his presence from interfering in or influencing any behaviors stat meth

observation tube >>> eyepiece

ocDNA: an open circular DNA molecule that has at least one nick; it cannot be supercoiled and has the same density as linear DNA in CsCl2/EB density gradients biot

ochre codon: UAA stop codon gene biot >>> nonsense mutation

octopine: a rare derivate of an amino acid; it is produced in some crown galls of plants; the controlling genes are part of the T-DNA of Ti plasmids chem phys

octoploid: having eight chromosome sets of identical or different complements cyto

octovalent: chromosome configuration consisting of eight chromosomes cyto

ocular >>> eyepiece

OECD >>> Organization for Economic Cooperation and Development

off-grade: postharvest removal of pathogen-infested or damaged fruit, seeds, or plants by screening procedures; the culled or off-graded material can later be individually analyzed or discarded meth

offset: a young plant produced by the parent, usually as its base (offshoot) or a small bulb at the base of a mother bulb bot

offspring >>> progeny

off-type: an individual differing from the population norm in morphological or other traits; the term also includes escapes and contaminants (e.g., seeds that do not conform to the characteristics of a variety, uncontrolled self-pollination during production of hybrid seed, segregates from plants, etc.) gene agr

Ohio method >>> ear-to-row selection

oidium: the generic name given to the conidial stage of all >>> powdery mildews, the Erysiphales; the conidia are consistently similar throughout this family, being unbranched and producing chains of hyaline, i. e., oval conidia phyt

oil crops: plants that are grown for oil or oil-like products; main oil crops are: castor, peanut, rapeseed, safflower, sesame, soybean, sunflower, crambe, niger, jojoba, and poppy agr

oil immersion: the oil that is placed between the lens of a microscope and the coverslip above a microscopical preparation micr

oil legumes >>> oil crops

oil poppy >>> oil crops

oil-immersion objective: the objective lens system used for highest resolution with the light microscope; the space between the coverslip over the object to be examined and the lens is filled with a drop of oil of the same refractive index as the glass micr

oilseed >>> oil crops

OKAYAMA-BERG procedure: a method of cDNA cloning using specialized vectors favoring the generation of full-size clones biot

olein: a colorless to yellowish, oily, water-insoluble liquid, C57H104O6, the triglyceride of oleic acid, present in many vegetable oils chem phys

oligocarpous - wenigfrüchtig adj: bearing less than the typical amount of fruit bot

oligogene: a gene that produces a pronounced phenotypic effect on characters that show normal inheritance gene

oligogenic: inheritance due to a small number of genes with discernible effects gene

oligogenic resistance: resistance controlled by one or a few genes phyt

oligomer: a protein composed of two or a few identical polypeptide subunits chem phys

oligonucleotide (oligos): a small piece of ssDNA or ssRNA; oligos are synthesized by chemically linking together a number of specific nucleotides; they are used as synthetic genes and DNA probes or in site-directed mutagenesis biot

oligopeptide: a small protein composed of 5-20 amino acids chem phys

oligos >>> oligonucleotide

oligospermous: showing only few seeds bot

omnipotency >>> totipotency

omnivorous: of parasites, or attacking a number of different hosts phyt

once blooming: it refers to plants or varieties (e.g., in roses) that bloom once a year hort

one-gene-one-enzyme (polypeptide) hypothesis: the hypothesis that a large class of structural genes exists in which each gene encodes a single polypeptide that may function either independently or as a subunit of a more complex protein; originally it was thought that each gene encoded the whole of a single enzyme, but it has since been found that some enzymes and other proteins derive from more than one polypeptide and hence from more than one gene gene bio

one-point crossover: in genetic algorithms, a breeding technique using one randomly chosen point, interchanging the portions of the two breeding individuals to the right of that point stat

ontogenesis: the course of growth and development of an individual from zygote formation to maturity phys


ontogeny >>> ontogenesis

oogonium: a primordial germ cell that gives rise, by mitosis, to oocytes, from which the ovum and polar bodies develop by meiosis bot

opal: a UAG stop codon biot >>> nonsense mutation

opaque: partially pervious to light bot

opaque (–2) maize (mutant): a mutant form that produces proteins rich in lysine and higher in content of calcium, magnesium, iron, zinc, and manganese gene

open continuous culture: a cell culture in which inflow of fresh medium is balanced by outflow of a corresponding volume of culture biot >>> closed continuous culture >>> continuous culture

open pollination: natural, cross, or random pollination; a free gene flow bot

open storage: storage with free access to normal atmospheric conditions seed

open-pollinated crossing group >>> crossing group(s)

open-reading frame (ORF): the mRNA region between the start and stop codon gene

operator (gene): a region of DNA at one end of an operon that acts as the binding site for a specific repressor protein and so controls the functioning of adjacent cistrons gene

operon: a set of adjacent structural genes whose mRNA is synthesized in one piece, together with the adjacent regulatory genes that affect the transcription of the structural genes; it is under the control of an operator gene, lying at one end of it gene

opine: a group of unusual amino acid derivatives produced by plant cells transformed by Agrobacterium inorder to feed the pathogen; opines include agropines, nopalines, octopines and are characteristic for individual strains of Agrobacterium biot

opposite: applied to the leaf arrangement in which leaves arise in pairs, one pair at each node bot

optic chiasma: it refers to a visible chiasma on meiotic chromosomes through the microscope cyto

optical density (OD): a logarithmic unit of transmission; OD = –logT (transmission), for example, a change of the optical density from 1 to 2 represents a tenfold increase in absorption micr

optical mapping: an enabling technology for whole genome analysis, which involves the capture of individual DNA molecules, obtained directly from genomic DNA, followed by digestion in situ by selected restriction endonucleases; the resulting fragments are then visualized directly to produce detailed optical restriction maps; this methodology allows patterns of sequence variation to be detected across entire genomes, without the need for DNA amplification, and, unlike other genomewide scanning methods, provides detailed haplotype information by analyzing individual DNA molecules meth biot cyto

optimal sampling strategy: a sampling strategy that ensures that the genetic diversity of a species is represented in the samples stat meth

opuntia: within the subtribe Opuntioideae there are several species used as crop and horticultural plants; edible fruits and fleshy parts of the plant; special use for production of the stain “carmine red” by the ecto-parasite Cochenille (Dactylopius coccus) bot

orangery: a sheltered place, especially a greenhouse, used for the cultivation of orange trees and other tropical or subtropical plants in cool climates meth hort

orcein: a dye used in cytology; it is dissolved in acetic acid and used for staining of squash preparations of chromosomes cyto meth prep

orchard: an area of land devoted to the cultivation of (fruit or nut) trees hort

ordinal scale: a scale for scoring quantitative data using a series of predefined intervals arranged in a logical sequence (e.g., a typical ordinal scale may involve responses of “very good”, “good”, “satisfactory”, “poor”, or “very poor”) stat

ordinary least squares: the estimator that minimizes the sum of squared residuals stat

organ asymmetry: in many plants the left and right halves of their organs have distinct shapes (e.g., the leaves of Begonia, Tilia (lime tree), Ulmus (elm) and petals of Anhirrhinum (snapdragon) or Pisum (pea) flowers; they can occur in two mirror-image forms, left handed and right-handed; in many cases these two forms occur in equal numbers on the plant, either being located opposite each other or alternating along the stem; asymmetry of each organ traces back to a meristem with a single plane of symmetry (bilateral symmetry), such that mirror-image organs arise from opposite halves of the meristem bot

organ culture: the growth in aseptic culture of plant organs, such as roots or shoots, beginning with organ primordia or segments and maintaining the characteristics of the organ biot

organelle: within a cell, a persistent structure that has a specialized function; mostly separated from the rest of the cell by selective membranes bot

organic soil: a soil that is composed predominantly of organic matter; it usually refers to peat agr

Organization for Economic Cooperation and Development (OECD): an international agency which, among other things, has developed specifications, procedures and standards for international seed certification among member countries seed org

organogenesis: the initiation and growth of an organ from cells or tissue phys

organogenetic: it refers to cells or tissue able to form organs biot

organogenic >>> organogenetic

organo-metallic complex: a general term referring to compounds in which metal ions have been complexed by organic compounds, e.g., chelates; while all chelates are complexes, all complexes are not chelates agr chem. >>> siderophore

ornamental plant: a plant that is grown for visual display; it describesany plant cultivated for decorative purposes; plants classified as ornamental are generally contrasted with those grown as food sources, though there are other, non-ornamental uses for plants hort

ornamentals >>> ornamental plant

ornithogamy >>> ornithophily

ornithophilous >>> ornithophily

ornithophily: pollination by birds bot

orphan crop(s): those crops which are typically not traded internationally but which can play an important role in regional food security; many of these crops have received little attention from crop breeders or other research institutions agr >>> minor crop

orphan gene: a gene identified by sequencing; its function is unknown gene

ortet: the original plant from which a clone is started through rooted cuttings, grafting, tissue culture, or other means of vegetative propagation (e.g., the original plus tree used to start a grafted clone for inclusion in a seed orchard) meth hort fore >>> cutting

orthodox seed: seed that can be dried and stored for long periods at reduced temperatures and under low humidity seed

orthogonal design: a design, where the various factors in the design are orthogonal in the sense of partitions stat

orthogonality: it is considered to be one of the most important features for design of experiment stat

orthologous genes: homologous genes that have become differentiated in different species derived from a common ancestral species, as opposed paralogous genes gene

orthoploid >>> euploid

oryzalin: an agent that is efficient for chromosome doubling of haploid apple shoots in vitro; also shoot tips of diploid roses can be treated in vitro at concentrations of 5 to 15 µM; tetraploid shoots can be obtained in highest frequencies after exposure to 5 µM oryzalin for 14 days; thin (1 mm) nodal sections can be treated with 5 µM oryzalin for only 1 day meth cyto

oryzinin >>> glutenin

osmolarity: the total molar concentration of the solutes affecting the osmotic potential of a solution or nutrient medium phys

osmolyte: osmolytes are osmolytic active, neutral organic compounds, such as sugars (polyols), certain amino acids, and quaternary ammonium compounds; proline is the most widely distributed compatible osmolyte; there is a strong correlation between increased cellular proline levels and the capacity to survive both water deficit and the effects of high environmental salinity phys

osmosis: the net movement of water or of another solvent from a region of low solute concentration to one of higher concentration through a semipermeable membrane phys

other crop seed: one of the four components of a purity test; the total percentage (by weight) of seed of all crop species, each comprising less than 5 % of the seed lot seed

O-type: a maintainer plant in sugarbeet breeding; it carries the same sterility genes as the male sterile plants but having the normal cytoplasm—(N)xxzz; this genotype exists at low frequencies (3-5 %) in most sugarbeet populations; it can be identified only by test-crossing prospective O-types with CMS plants; if all the offspring from a test cross are male sterile, the test-crossed pollinator plant is of the O-type genotype; by repeated selfing of an identified O-type, and simultaneous repeated backcrossing to a CMS line, inbred O-type lines and their equivalent inbred CMS lines can be developed seed

ounce (oz): equals 31.1030 g

outbreeding: the crossing of plants that are not closely related genetically, in contrast to inbreeding, in which the individuals are closely related bot

outclassed: it refers to a crop variety that is taken away from registration seed

outcrossing: cross pollination between plants of different genotypes bot gene; in biotechnology, the transfer of a given gene or genes (e.g., one synthesized by humans and inserted into a plant via genetic engineering) from a domesticated organism (e.g., crop plant) to wild type (relative of crop) biot eco

outgrades (in potato): outgrades are tubers considered unmarketable because of size, disease, greening, second growth, or slug or mechanical damage seed

outlier: an individual that occurs naturally some distance away from the principal area in which its population is found; they are anomalous values in the data and can be due to recording errors, which may be correctable or they may be due to the sample not being entirely from the same population stat

outplant: a seedling, transplant, or cutting ready to be established on a certain site agr fore hort

ovary: the part of the flower that develops into the grain in grasses; the ovary has one or more ovules, each containing an embryo sac bot >>> Figure 35 >>> Table 8

ovary wall >>> pericarp

ovate: egg-shaped; having an outline like that of an egg, with the broader end basal bot >>> ovoid

overall resistance: resistance to disease expressed at all plant growth stages phyt

overdominance: the phenomenon in which the character of the heterozygotes is expressed more markedly in the phenotype than in that of either homozygote; usually the heterozygote is fitter than the two homozygotes; this can give rise to monohybrid heterosis when the hybrid vigor obtained by crossing parents differing in a single specified pair of allelic genes gene >>> Tables 20, 21

overhang: 3' and 5' ssDNA overhangs of dsDNA; overhangs may also be called extensions or sticky ends biot

overlapping code >>> overlapping DNA (segments)

overlapping DNA (segments): a special type of gene organization; one DNA sequence may code for different proteins; it is performed by two open reading frames, which subsequently act gene

overseeding: seeding into an existing crop stand or turf agr

overstocked: the situation in which trees are so closely spaced that they are competing for resources, resulting in less than full-growth potential for individual trees fore

overstored seeds >>> method of overstored seeds

overstory: the canopy in a stand of trees; in contrast to the understory which is low growing woody or herbaceous vegetation forming a layer beneath the overstory fore

oversummering: the survival through the summer and/or to keep alive through summer agr

overwintering: the survival through the winter and/or to keep alive through winter agr

ovoid: egg-shaped bot >>> ovate

ovule: a structure in angiosperms and gymnosperms that, after fertilization, develops into a seed bot

ovule primordium: meristematic tissue of the ovary wall from which the seeds of angiosperms originate bot

ovum >>> egg

oxalate oxidase: an enzyme detected in, for example, barley seedling roots soon after germination and in the leaves of mature plants, and in response to powdery mildew infection; the enzyme contains manganese; the enzyme shows almost identical structure to the wheat protein germin phys

oxalic acid: a white, crystalline, water-soluble, poisonous acid, H2C2O4·2H2O, used for bleaching and as a laboratory reagent chem phys

oxidase: an enzyme that catalyzes reactions involving the oxidation of a substrate using molecular oxygen as an electron acceptor chem phys

oxidation: a reaction in which atoms or molecules gain oxygen or lose hydrogen or electrons chem phys

oxidative burst an early defence response against pathogens where 10-14 mol H2O2 per cell per second is generated; the early oxidative burst (phase I) is common for compatible and incompatible interactions, the later, but sustained (phase II) is associated with hypersensitive response/reaction phyt

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