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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 or in modified design as book by CRC Press, Taylor & Francis Group, Boca Raton, USA

UAG stop codon >>> amber codon

UGMS >>> unigene derived microsatellite markers

ultracentrifugation: centrifugation carried out at high rotor speeds (<100,000 rpm) and therefore under high centrifugal forces (<750,000 g) meth

ultracentrifuge: a set-up for high-speed centrifugation between 65,000-100,000 rounds per minute prep

umbel: an inflorescence in which all the pedicels arise at the apex of an axis bot

umbellate >>> umbelliferous plants

umbelliferous plants: tap-rooted plants with minute flowers aggregated into flat or umbrella-shaped heads (e.g., carrot, parsnip, celery, dill, parsley, etc.) bot

unavailable nutrients: plant nutrients that are present in the soil but cannot be taken up by the plant roots because they have not been released from the rock by weathering or from organic matter agr

unavailable water: water that is present in the soil but cannot be taken up by the roots because it is strongly adsorbed on to the surface of particles agr

unbalanced diallelic: a genotype involving a multiple allelic locus in autotetraploids where two alleles are represented an unequal number of times gene

unbalanced experimental design: an experiment or set of data in which all treatments or treatment combinations are not equally represented; a common cause of unbalanced experiments is unequal mortality among entries in a test meth >>> randomized-block design

unbalanced translocation: a type of chromosome translocation in which a loss of chromosomal segments results in a deleterious genetic effect cyto

uncomplete block design >>> incomplete block design

unconscious selection: indirect selection by breeders (sometimes called “parallel selection”) when in addition to a target characteristic another trait is taken to the next generation; it can be a morphological, biochemical, or physiological trait genetically linked to the target characteristic meth

underplant crop: in horticulture, adding one or more complementary, low-growing plants beneath and around taller plants hort; in agriculture, main crops can be underplanted with vegetables; it helps these plants to have some shade in the heat of the summer and one can often get a crop longer than otherwise; wide ranges of combinations between main and underplant crops are possible and are applied for several purposes agr

underreplication: certain heterochromatic chromosome regions and ribosomal DNA that show a slower replication as compared to the remaining genomic DNA gene

understock: the bottom or supporting part of a graft composed of either root or stem tissue or both hort >>> rootstock >>> graft

understocked: a stand of trees so widely spaced that, even with full growth potential realized, crown closure will not occur; understocking indicates a waste of resources, as the site is not fully occupied fore

unequal crossing-over: a crossing-over after improper pairing between chromosome homologues that are not perfectly aligned; the result is, for example, one crossing-over chromatid with one copy of the segment and another with three copies cyto >>> Figure 24

uneven-aged stand: a group of trees of a variety of ages and sizes growing together on a uniform site fore

unicellular: an organism consisting of one cell, e.g., yeast bot bio

unifactorial >>> monogenic

uniflorous: showing one flower only bot

uniform crossover: in genetic algorithms, a breeding technique in which it is randomly decided for each element of a breeding pair of individuals whether they should be switched stat

uniformity: describes the state of a population or group in which all the individuals are genetically identical; it is a typical feature of clonal varieties (e.g., potato); in general, lack of diversity within and between plant species is apparent in modern cultivars gene seed

unigene derived microsatellite (UGMS) marker(s): a specific type of molecular markers having the advantage of assaying variation in the expressed component of the genome with unique identity and positions biot

unilateral: the type of panicle (e.g., in oats) where the branches are all turned to one side like a pennant bot

unilateral inheritance: inheritance that is associated with linkage in sex chromosomes gene

uninemic chromosome: a >>> chromosome consisting of one double helix of DNA cyto

Union for Protection of New Varieties of Plants: Union pour la Protection des Obtentions Vegetales (UPOV); it is an intergovernmental organization with headquarters in Geneva, Switzerland; it is based on the International Convention for the Protection of New Varieties of Plants, as revised since its signature in Paris on December 2, 1961; on April 16, 1993, the Union consisted of 23 member States; the objective of the convention is the protection of new varieties of plants by an intellectual property right

unipolar (spindle): a cell spindle with only one pole cyto

unique event polymorphisms (UEPs): single nucleotide polymorphisms (snips or SNP's) in which a particular nucleotide is changed; since they are very rare, they also are known as unique event polymorphisms biot meth

unique identifier: an international >>> GMO identification code; every genetically modified organmism that receives authorisation is given a "unique identifier" consisting of nine letters and/or numbers; the first two or three characters indicate the company submitting the application, while the final five or six characters specify the respective transformation event; the last digit serves as a verifier; the identification code, known internationally as the unique identifier, was established by the >>> OECD; the OECD is now overseen by the >>> EU and forms the basis for the legally mandated system of traceability biot org

unisexual: a flower that possesses either stamens or carpels but not both (i.e., a plant possessing only male or female flowers) bot

United States Department of Agriculture (USDA): the U.S. agency responsible for regulation of biotechnology products in plants and animals; the major laws under which the agency has regulatory powers include the Federal Plant Pest Act (PPA), the Federal Seed Act, and the Plant Variety Act (PVA); in addition, the Science and Education (S and E) division has nonregulatory oversight of research activities that the agency funds agr

univalent: a single chromosome observed during meiosis when bivalents are also present; it has no pairing mate cyto >>> Figure 15

univalent shift: a spontaneous change in monosomy from one chromosome to another; it is caused by partial asynapsis or desynapsis during meiosis cyto

univalent switch >>> univalent shift

universe >>> population stat

unloader: a device on a combine to transport the grains from a bunker to a transporter agr

unreduced gametes: gametes not resulting from common meiosis, and so showing the number of chromosomes per cell that is characteristic of a sporophyte; they spontaneously arise as a consequence of irregular division in anaphase I of meiosis; they may contribute to spontaneous (meiotic) polyploidization; in rye, they were used for production of tetraploids via valence crosses cyto

unsaturated fatty acid: a fatty acid that has a double bond between the carbon atoms at one or more places in the carbon chain; hydrogen can be added at the site of the double bond chem phys

unspecific resistance >>> horizontal resistance

upgrading: the reprocessing of a seed lot to remove low quality seeds or other materials; the remaining seeds are of higher quality than the original seed meth

UPOV >>> Union for Protection of New Varieties of Plants >>> organizations

upper palea: upper glume >>> pale

upstream: a term used for description of the position of a DNA sequence within a DNA or protein molecule; it means that the position of the sequence lies away from the direction of the synthesis of a DNA or protein molecule gene

uracil (U): a pyrimidine base that occurs in RNA and constituent of nucleotides and as such one member of the base pair A-U (adenine-uracil) chem gene

urban forestry: the management of vegetation, particularly trees and forests, to improve the urban environment and the quality of life of people who live, work, and spend their leisure time in urban and urbanizing landscapes fore >>> forestry

urea: a compound, CO(NH2)2, occurring in urine and other body fluids as a product of protein metabolism; an important plant fertilizer chem agr

uredospore: a sexual spore of the rust fungi bot

ureide: ureides (allantoin and allantoic acid) are important storage and translocatory forms of nitrogen in nodulated legumes; these are synthesized within the nodules; many tropical legumes including export nitrogen from the nodule in the form of ureides phys

USDA >>> United States Department of Agriculture

USDA-ARS >>> United States Department of Agriculture, Agricultural Research Service >>> organizations

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