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Amarillo slim

Concise glossary of breeding terms

Allele: a gene that is found in one of two or more different forms in the same position in a chromosome


Backcross: a cross of a hybrid to either of its parents. In genetics, a cross of a heterozygote to a homozygous recessive. (See test cross)

Backcross Breeding: A system of breeding whereby recurrent backcrosses are made to one of the parents of a hybrid, accompanied by selection for a specific character or characters.


Biotype: A group of individuals with the same genotype. Biotypes may be homozygous or heterozygous.


Breeding: The art and science of changing plants or animals genetically.


Bulk Breeding: The growing of genetically diverse populations of self-pollinated crops in a bulk plot with or without mass selection, followed by single-plant selection.
Bx1, Bx2, Bx3... Symbols that are used to designate first, second, third, etc backcross generations (crossing back to one of the two cultivars used in the initial hybrid)


Character: (trait) An attribute of an organism resulting from the interaction of a gene or genes with the environment.


Chromosomes: Structural units of the nucleus which carry the genes in linear order. Chromosomes undergo a typical cycle in which their morphology changes drastically in various phases of the life cycle of the organisms.


Cultivar: a plant variety that has been produced in cultivation by selective breeding.  (Traditionally referred to as strains)  


Dominance: Intra-allelic interaction such that one allele manifests itself more or less, when heterozygous, than its alternative allele.


Donor Parent: The parent from which one or a few genes are transferred to the recurrent parent in backcross breeding.


Double Cross: A cross between two F1 hybrids.


Dioecious: having the male and female reproductive organs in separate individuals.


F1: The first generation of a cross.

F2: The second filial generation obtained by self-fertilization or crossing F1 individuals.

F3: Progeny obtained by self-fertilization or crossing of F2 individuals.


Family: A group of individuals directly related by descent from a common ancestor.


Fertilization: Fusion of the nuclei of male and female gametes.


Gamete: Cell of meiotic origin specialized for fertilization.


Gene: The unit of inheritance. Genes are located at fixed loci in chromosomes and can exist in a series of alternative forms called alleles.

Gene Frequency: The proportion in which alternative alleles of a gene occur in a population.

Gene Interaction: Modification of gene action by a non-allelic gene or genes.

Germplasm: The sum total of the hereditary materials in a species.

Genome: A set of chromosomes corresponding to the haploid set of a species.

Genotype: The entire genetic constitution of an organism.


Heritability: The proportion of observed variability which is due to heredity, the remainder being due to environmental causes. More strictly, the proportion of observed variability due to the additive effects of genes.

Heterosis: Hybrid vigour such that an F1 hybrid falls outside the range of the parents with respect to some character or characters. Usually applied to size, rate of growth, or general thriftiness.

Heterozygous: Having unlike alleles at one or more corresponding loci (opposite of homozygous).


Hybrid: The product of a cross between genetically unlike parents.


Inbred Line (IBL): A line produced by continued inbreeding. In plant breeding, a nearly homozygous line usually originating by continued self-fertilization, accompanied by selection.


Inbreeding: The mating of individuals more closely related than individuals mating at random.


Intersex: An individual baring both male and female parts simultaneously. 


Line Breeding: A system of breeding in which a number of genotypes, which have been progeny tested in retrospect to some character or group of characters, are composited to form a variety.


Locus: The position occupied by a gene in a chromosome.  (plural loci) 

Mass Selection: A form of a selection in which individual plants are selected and the next generation is propagated from all of their seeds.


Meiosis: A double mitosis occurring in sexual reproduction which results in production of gametes with haploid (n) chromosome number.


Mitosis: The process by which the nucleus is divided into two daughter nuclei with equivalent chromosome complements, usually accompanied by division of the cell containing the nucleus.


Monoecious: Staminate and pistillate flowers born separately on the same plant.

Mutation: A sudden heritable variation in a gene or in a chromosome structure.


Outcross: A cross, usually natural, to a plant of different genotype.


P1, P2, P3,...: Symbols for designating. First second, etc., generations from a parent. Also used to designate different parents used in making a hybrid or series of hybrids. 


Pedigree: A record of the ancestry of an individual, family, or strain..


Phenotype: Appearance of an individual as contrasted with its genetic make-up or genotype. Also, used to designate a group of individuals with similar appearance but not necessarily identical genotypes.


Polycross: Open pollination of a group of genotypes (generally selected), in isolation from other compatible genotypes, in such a way as to promote random mating.


Populations: In genetics, a community of individuals which share a common gene pool. In statistics, a hypothetical and infinitely large series of potential observations among which observations may actually constitute a sample.


Progeny Test: A test of the value of a genotype based on the performance of its offspring produced in some definite system of mating.


Pure Line: A strain homozygous at all loci, ordinarily obtained by successive self-fertilizations in plant breeding.


Qualitative Character: A character in which variation is discontinuous.

Quantitative Character: A character in which variation is continuous so that classification into discrete categories is not possible.


Recessive: The member of an allelic pair which is not expressed when the other (dominant) member occupies the homologous chromosome.


Reciprocal Crosses: Crosses in which the sources of the male and female gametes are reversed.


Recombination: Formation of new combinations of genes as a result of segregation in crosses between genetically different parents. Also, the rearrangement of linked genes due to crossing over.

Recurrent Parent: The parent to which successive backcrosses are made in backcross breeding.

Recurrent Selection: A method of breeding designed to concentrate favorable genes scattered among a number of individuals by selecting, each generation, among the progeny produced by matings of the selected individuals (or their selfed progeny) of the previous generation.


Resistance: The restriction of development of a pathenogenic agent or parasite. Can vary in degree from immunity (no development) to only slight retardation relative to a socalled susceptible reaction.


Reversal:  Changing the sexual expression on an individual by altering hormonal balance.


S1, S2, S3...: Symbols for designating first, second, third, etc. selfed generations from an ancestral plant (S0).


Segregation: Separation of paternal from maternal chromosomes at meiosis and consequent separation of genes leading to the possibility of recombination in the offspring.

Selection: In genetics, discrimination among individuals in the number of offspring contributed to the next generation. In statistics, discrimination in sampling leading to bias. 
Self-Fertilization: (Selfing) Fusion of male and female gametes from the same individual.

STS: Short for Silver thiosulfate, the chemical most often used for preforming reversals.


Variation: The occurrence of differences among individuals due to differences in their genetic composition and/or the environment in which they were raised.

Variety: A subdivision of a species. A group of individuals within a species which are distinct in form or function from other similar arrays of individuals.





NLD: Narrow leaf drug. Cannabis indica ssp. Indica.  Most commonly found in Africa, southern Asia, south and central America, middle east. Australia, USA etc.  (Traditionally referred to as Sativas)


BLD:  broad leaf drug. Cannabis Indica ssp. Afghanica. Originating from Afghanistan/Pakistan, Introduced into USA, Australia etc around the 1970’s (traditionally referred to as indicas) 





Robert W. Allard Principles of plant breeding (second edition).


Robert C. Clarke & Mark D. Merlin Cannabis evolution and ethnobotany.



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Thank you 

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Really helpfully to have that all in one place

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