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Inbreeding depression in Delphinium nelsonii. A. Overall fitness of progeny cohorts and the B. progeny lifespan were all lower when progeny were the result of crosses with pollen taken close to a receptor plant. [1] Inbreeding depression is the reduced biological fitness that has the potential to result from inbreeding, the breeding of related ...
Inbreeding depression occurs when related parents have children with traits that negatively influence their fitness largely due to homozygosity. In such instances, outcrossing should result in heterosis. Not all outcrosses result in heterosis.
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. Inbreeding can significantly influence gene expression which can prevent inbreeding depression. [13]
Previous research, comparing measures of dominance, overdominance and epistasis (mostly in plants), found that the majority of cases of heterozygote advantage were due to complementation (or dominance), the masking of deleterious recessive alleles by wild-type alleles, as discussed in the articles Heterosis and Complementation (genetics), but ...
A review of the genetics of inbreeding depression in wild animal and plant populations, as well as in humans, led to the conclusion that inbreeding depression and its opposite, heterosis (hybrid vigor), are predominantly caused by the presence of recessive deleterious alleles in populations. [7]
In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. [1] The concept is in contrast to inbreeding depression , although the two effects can occur simultaneously on different traits. [ 2 ]
Inbreeding and selection for uniformity for multiple generations ensures that the parent lines are almost homozygous. The divergence between the (two) parent lines promotes improved growth and yield characteristics in offspring through the phenomenon of heterosis ("hybrid vigour" or "combining ability").
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 ...