Inbreeding

Study Notes

Inbreeding leads to an increase in homozygosity and a decrease in vigor.
Hybrid vigor, or heterosis, is related to an increase in heterozygosity.
Inbreeding is used to obtain homozygous individuals for pure lines and hybridization.
Inbreeding depression is a reduction in vigor due to increased homozygosity.
Inbreeding can result in homozygous recessive or dominant genotypes with valuable traits.
Homozygous recessive forms can be easily recognized and eliminated.
The degree of inbreeding is the proportion of homozygotes in consanguineous groups.
Heterozygosity is reduced through successive generations of inbreeding until all genotypes become homozygous.
The genotypic proportions change with each generation of inbreeding.
Inbreeding can occur in plants with separate sexes when partners are related.
Inbreeding leads to homozygosity and decreased genetic variability.
Heterosis is achieved by crossing genetically different, inbred lines.
Obtaining inbred lines involves choosing biological material, obtaining the lines, testing their combinative capacity, and producing F1 hybrids.
Inbreeding involves self-fertilization for multiple generations.
Self-incompatibility can make obtaining inbred lines difficult in some species.
Once obtained, inbred lines can be crossed to find the best combinations for heterosis in the F1 generation.
Combinative capacity of inbred lines is determined through dialel or cyclic hybridization with a common tester.
Specific combining capacity is determined to identify the most valuable components for commercial hybrids.
Double hybrids are preferred for safer and cheaper seed production.
Production of double hybrids can be specified based on the production of simple hybrids.