Accession: A distinct, uniquely identifiable sample of seeds representing a cultivar, breeding line or a population, which is maintained in storage for conservation and use. Accession number: A unique identifier that is assigned by the curator when an accession is entered into a collection. This number should never be assigned to another accession. Achene: A one-seeded dry indehiscent fruit with the seed attached to the pericarp at only one point. Active collection: A germplasm accession that is used for regeneration, multiplication, distribution, characterization and evaluation. Active collections are maintained in short- to mediumterm storage and usually duplicated in a base collection maintained in medium- to long-term storage. Bar-coding: ( Seed Processing, Seed Cleaning, Stone separator, Combo Cleaner, Grading Machine, Gravity Separator ) A computerized coding system that uses a printed pattern or bars on labels to identify germplasm accessions. Barcodes are read by optically scanning the printed pattern and using a computer program to decode the pattern. Base collection: A collection of germplasm that is conserved in long-term, secure storage and is not used as a routine distribution source. Seed is usually stored at sub-zero temperatures and low moisture content. Base unit: The number of seeds needed to ensure the successful implementation of a procedure such as registration or regeneration. Breeding line: A group of identical pure-breeding diploid or polyploid organisms that are distinguished from other individuals of the same species by a unique phenotype and genotype. Capsule: A dry dehiscent fruit derived from an ovary with two or more carpels that splits partly open at maturity. Characterization: The recording of highly heritable characters that can be easily seen and are expressed in all environments. Collection: A group of germplasm accessions maintained for a specific purpose under defined conditions. 124 Handbooks for Genebanks No. 8 Cultivar: A crop variety produced by scientific breeding or farmerselection methods. Database: An organized set of interrelated data assembled for a specific purpose and held in one or more storage media. Database management ( Seed Processing, Seed Cleaning, Stone separator, Combo Cleaner, Grading Machine, Gravity Separator ) system: A piece of software that controls the organization, storage, retrieval, security and integrity of data in a database—it accepts requests from the application and instructs the operating system to transfer the appropriate data. The major vendors are Oracle, IBM, Microsoft and Sybase. MySQL is a very popular open-source product. Dehiscent fruits: Fruits that open at maturity to shed their seeds (see follicle, capsule). Descriptor: An identifiable and measurable trait, characteristic or attribute observed in an accession that is used to facilitate data classification, storage, retrieval and use. Descriptor list: A collection of all individual descriptors of a particular crop or species. Desiccator: A short glass jar fitted with an air-tight cover and containing a desiccating agent such as silica gel or ( Seed Processing, Seed Cleaning, Stone separator, Combo Cleaner, Grading Machine, Gravity Separator )calcium chloride, above which the material to be dried is supported on a perforated platform. Distribution: The process of supplying samples of germplasm accessions to breeders and other users. Documentation: The organized collection of records that describe structure, purpose, operation, maintenance, and data requirements. Donor: An institution or individual responsible for donating germplasm. Dormancy: The state in which certain live seeds do not germinate, even under normally suitable conditions. Exploration: The act of searching for genetic diversity in the field. Equilibrium moisture content: The moisture content at which a seed is in equilibrium with the relative humidity of the surrounding air. Evaluation: The recording of those characteristics whose expression is often influenced by environmental factors. Ex situ conservation: The conservation of biological diversity outside its natural habitat—in the case of plant genetic resources, 125 Manual of Seed Handling this may be in seed genebanks, in vitro genebanks or as live collections in field genebanks. Field collection: A collection of germplasm maintained as living plants—germplasm that would otherwise be difficult to maintain as seed is commonly maintained in field collections. Follicle: A dry, single-celled, many-seeded fruit consisting of a single carpel, dehiscing by the ventral suture. Funicle: A stalk by which an ovule or seed attaches itself to the fruit wall. Genebank: A centre for conserving genetic resources under suitable conditions to prolong their lives. Genetic diversity: The variety of genetic traits that result in differing characteristics. Genetic drift: Changes in the genetic composition of a population when the number of individuals is reduced below the frequency of certain alleles within it. Genetically modified organism (GMO): An organism whose genetic material has been ( Seed Processing, Seed Cleaning, Stone separator, Combo Cleaner, Grading Machine, Gravity Separator ) deliberately altered (see also transgenic plant). Genotype: The genetic constitution of an individual plant or organism. Germplasm: The genetic material that forms the physical basis of heredity and that is transmitted from one generation to the next by germ cells. Germination: The biological process that leads to the development of a seedling from a seed. Radicle emergence is the first visible sign of germination, but may be followed by no further growth or by abnormal development. According to ISTA rules, only seedlings showing normal morphology are considered to have germinated. Germination test: A procedure to determine the percentage of seeds that are capable of germinating under a given set of conditions. Hard seeds: Seeds that fail to imbibe and germinate when placed in a moist medium because they are impermeable to water. Humidification: The process in which the moisture content of very dry seeds is raised by placing them in a humid environment; humidification helps to prevent damage to seeds from rapid uptake of water. Imbibition damage: Damage caused by rapid uptake of water in very dry seeds (see also humidification). 126 Handbooks for Genebanks No. 8 Indehiscent fruit: Fruit that does not open at maturity (see also achene). In vitro collection: A germplasm collection maintained as plant tissue ranging from protoplast and cell suspensions to callus cultures, meristems and embryos. Inventory: A list of samples (and their characteristics) that is stored in a genebank. Isotherm: A graph showing the relationship between seed moisture content and percentage relative humidity (see also sorption isotherms). Laminated aluminium foil packets: Packets constructed of a laminate consisting of an ( Seed Processing, Seed Cleaning, Stone separator, Combo Cleaner, Grading Machine, Gravity Separator ) inner layer of polyethylene, a middle layer of aluminium foil and an outer layer of polyester. Landrace: A crop cultivar that has evolved through many years of farmer-directed selection and that is specifically adapted to local conditions; landraces are usually genetically heterogeneous. Long-term conservation: The storage of germplasm for a long period, such as in base collections and duplicate collections. The period of storage before seeds need to be regenerated varies, but is at least several decades and possibly a century or more. Long-term conservation takes place at sub-zero temperatures. Mass maturity: The stage in development at which seeds attain maximum dry weight. Medium-term conservation: The storage of germplasm in the medium-term such as in active and ( Seed Processing, Seed Cleaning, Stone separator, Combo Cleaner, Grading Machine, Gravity Separator )working collections; it is generally assumed that little loss of viability will occur for approximately ten years. Medium-term conservation takes place at temperatures between 0°C and 10°C. Micropylar region: The point on a seed that was the orifice (pore) of the ovule. Moisture content (wet-weight basis): The weight of free moisture divided by the weight of water plus dry matter, expressed as a percentage. Monitoring: The periodic checking of accessions for viability and quantity. Monitoring interval: The period of storage between monitoring tests. Most original sample (MOS): A sample of seeds that have undergone the lowest number of regenerations since the material was acquired by the genebank, as recommended for storage as a 127 Manual of Seed Handling base collection. It may be a sub-sample of the original seed lot or a seed sample from the first regeneration cycle if the original seed lot required regeneration before storage. Multiplication: The representative sample of an accession grown to multiply the quantity of conserved material for distribution.
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