Advanced Backcross Breeding Glossary

One of the different forms of a gene (or marker) that can exist at a single locus. A single allele for each locus is inherited separately from each parent.

A breeding method used to move one or only a few desirable genes from a line (donor parent, often an agronomically poor or unadapted line) to an elite line (recurrent parent). This is done by crossing a donor parent to an elite line, and crossing offspring with the 'desired gene(s)' back to the elite parent.

After a plant has been transformed, the event must be moved into an elite genetic background. This is done by mating the transformed plant back to elite plants over several generations.

A breeding method used to move one or only a few desirable genes from a line (donor parent, often an agronomically poor or unadapted line) to an elite line (recurrent parent). This is done by crossing a donor parent to an elite line, and crossing offspring with the 'desired gene(s)' back to the elite parent.

The region of the chromosome associated with the attachment of the chromatids to the spindle fibers.

A distinguishing feature or attribute of individuals, groups, or categories.

A genetic structure in a cell composed of condensed DNA, which contains the genetic code for an organism.

The genetic structures in cells composed of condensed DNA, which contain the genetic code for an organism.

The deliberate mating of two parental types of organisms in genetic analysis.

The allele that is expressed in a heterozygous organism.

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

A crop line that has many genes for good agronomic traits that result in high yields in a particular environment.

The combinations of all the conditions external to the genome that potentially affect gene expression and the phenotype of a plant.

The fundamental unit of heredity that carries genetic information from one generation to the next. A gene is an ordered sequence of nucleotides located on a particular position on a particular chromosome that encodes a specific functional protein.

Creating a plant with a desired combination of two or more unique genes. This can be done when the genes are first transferred into the cells by co-transformation, or during the breeding process by crossing two lines that each contain a different gene resulting in progeny with both genes.

The allelic composition of a cell or organism.

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

An organism having two different alleles at one or more locations.

Having like alleles at corresponding loci on homologous chromosomes. An organism can be homozygous at one, several, or all loci.

An organism that has two identical alleles at one or more locations on a chromosome. Inbred lines are homozygous at many of their gene loci.

An individual produced by crossing two parents of different genotypes.

Mating between related organisms that leads to increased homozygosity.

Selection for the trait(s) of interest with little or no retention of lines not having the trait(s) of interest.

Plants within a species that have the same genetic composition and are genetically pure, (i.e., inbred line). Lines are typically experimental, not agronomically competitive (hence not commercially available), and are used only in plant breeding.

Plants within a species that have the same genetic composition and are genetically pure, (i.e., inbred line). Lines are typically experimental, not agronomically competitive (hence not commercially available), and are used only in plant breeding.

The association of genes on the same chromosome. The shorter the distance between two genes, the greater the probability they will be inherited together.

A type of cell division which results in the formation of gametes, cells with half the normal number of chromosomes.

Genes in the recurrent parent that are not at the locus of the gene of interest. Basically, nontarget genes are all those genes in the recurrent parent that the backcross breeder would like to retain in the backcrossing program.

The observable physical characteristics of an organism that are determined by a combination of the genetic composition (genotype) and the environment of the individual.

The observable physical characteristics of an organism that are determined by a combination of the genetic composition (genotype) and the environment of the individual.

The offspring of an organism.

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

A character in which variation is discontinuous.

A trait that will not be expressed phenotypically unless there are two copies of the gene allele (homozygous at the locus) present in an organism.

Recombination frequency is the frequency of crossovers between two genes. The map distance (in this case a genetic or recombinational map) is the recombination frequency between two genes times 100. For example, if the frequency of recombination is 0.10, the map distance is 10 map units.

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

The ability of an organism to survive and thrive in the presence of something that would normally cause damage or death, i.e., herbicide-resistant corn, Roundup-ready corn.

A collection of lines from a cross or population that is undergoing Mendelian or Hardy-Weinberg gene segregation.

A fundamental category of taxonomic classification, ranking below a genus or subgenus and consisting of related organisms capable of interbreeding.

Plant cells are grown in culture which allows them to be manipulated and then induced to develop into whole plants.

The characteristic that results from an expressing gene(s). Ex. Upright leaves, drought tolerance, Bt resistance. A trait can be influenced by the environment.

A process by which extra (foreign) genetic material is inserted into the cells of an individual without sexual hybridization.

The process of introducing foreign DNA into an organism which is then passed on to the organism’s progeny.

An organism that has a new genetically engineered DNA sequence found in every one of its cells. Genetically engineered organisms are transgenic. These two terms are used interchangeably.

Crop plants within a species that have the same genetic composition. Because plants in a self-pollinated crop are usually homozygous, the variety and their offspring will remain genetically pure (i.e., barley varieties).  Because plants in a cross-pollinated crop are usually heterozygous, the variety and their offspring will not remain genetically pure (i.e., hybrid corn varieties).

A relative reduction in yield observed in some hybrids or varieties compared with the yield observed in the most recently produced hybrids or varieties.