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Inbreeding is also used to reveal deleterious recessive alleles, which can then be eliminated through assortative breeding or through culling. In plant breeding, inbred lines are used as stocks for the creation of hybrid lines to make use of the effects of heterosis. Inbreeding in plants also occurs naturally in the form of self-pollination.
In plants, selfing can occur as autogamous or geitonogamous pollinations and can have varying fitness affects that show up as autogamy depression. After several generations, inbreeding depression is likely to purge the deleterious alleles from the population because the individuals carrying them have mostly died or failed to reproduce.
Almost no inbreeding depression occurs in self-fertilizing plants because the mode of reproduction allows natural selection to take place in wild populations of such plants. Critical steps in the improvement of self-fertilizing crops are the choice of parents and the identification of the best plants in segregating generations.
Therefore the coefficient of inbreeding of individual G is = (+) = + = %. If the parents of an individual are not inbred themselves, the coefficient of inbreeding of the individual is one-half the coefficient of relationship between the parents. This can be verified in the previous example, as 12.5% is one-half of 25%, the coefficient of ...
Mixed mating systems are generally characterized by the frequency of selfing vs. outcrossing, but may include the production of asexual seeds through agamospermy. [2] The trade offs for each strategy depend on ecological conditions, pollinator abundance and herbivory [ 3 ] and parasite load. [ 4 ]
Darwin's wife, Emma, was his first cousin, and he was concerned about the impact of inbreeding on his ten children, three of whom died at age ten or younger; three others had childless long-term marriages. [16] [17] [18] Humans do not seek to completely minimize inbreeding, but rather to maintain an optimal amount of inbreeding vs. outbreeding.
Inbreeding causes a decrease in the reproductive fitness of a population because of a decrease in its heterozygosity from the repeated mating of closely related individuals or selfing. [1] Inbreeding may also lead to inbreeding depression when heterozygosity is minimized to the point where deleterious mutations that reduce fitness become more ...
However, when genetically similar SI cultivars are bred, inbreeding depression can cause a cross-incompatible form of SC to arise, such as in apricots and almonds. [ 57 ] [ 58 ] In this rare, intraspecific, cross-incompatible mechanism, individuals have more reproductive success when self-pollinated rather than when cross-pollinated with other ...