Heterosis is often discussed as the opposite of inbreeding depression although differences in these. Genetic basis of inbreeding depression and heterosis. Study of heterosis and inbreeding depression under natural and water stress conditions in diverse maize hybrids. Potential optimal crosses for exploiting such heterosis are discussed, based on construction and the intermating of. When the heterosis is estimated over the mid parent, i. Inbreeding depression inbreeding depression and heterosis. Since the effective sizes of many endangered populations of salmon are on the order of 50 or smaller, this is a major potential source of longterm genetic. Inbreeding depression is essentially the opposite effect of heterosis hybrid vigour, which is the advantage gained from crossing lines or breeds.
This concept probably arises from the fact that inbreeding depression. Mechanisms of inbreeding depression and heterosis for. Based on inbreeding depression in f2 generation offspring from biparental crosses. Mechanisms of inbreeding depression and heterosis for profitable dairying bennet cassell extension dairy scientist, genetics and management virginia polytechnic institute and state university, blacksburg genes in diploid organisms operate singly, in pairs, and in conjunction with genes at other locations throughout the nuclear dna. Inbreeding depression an overview sciencedirect topics. Inbreeding depression refers to the reduced vigor in the offspring from matings involving related parents. Agriculture university jobner303329, jaipur, rajasthan, india email. Genetic basis of heterosis and inbreeding depression in. Some varieties of plants such as tomatoes, which can selfpollinate, have a much. Inbreeding depression of f2 progeny was also studied for 11 characters of 10 hybrids.
The role of inbreeding depression in heterosis and future research needs in the. Inbreeding depression is important in the evolution of outcrossing mating systems and, because intercrossing inbred strains improves yield heterosis, which is important in crop breeding, the genetic basis of these effects has been debated since the early twentieth century. Genetic basis of inbreeding depression and heterosis several hypothesis were put forward to explain inbreeding depression and conversely to explain the related phenomenon of hybrid vigour. Contributions of heterosis and epistasis to hybrid fitness core. Pdf study of heterosis and inbreeding depression under. Examples are lossoffunction mutations that are exposed in the homozygous recessive state. Two of them, proposed within the first decade after rediscovery of mendels work, claimed wide acceptance.
Julien f ayroles harvard university 24 publications 1,488. Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of. Mar 12, 2017 know about inbreeding and inbreeding depression, along with the degrees of depression. Significant heterosis was observed for most of the studied characters. Jun 04, 2017 the key difference between heterosis and inbreeding depression is that heterosis is the enhancement of traits due to the mixing of genes from two different individuals during outbreeding while inbreeding depression is the reduced biological fitness of offspring due to the increased homozygosity as a result of inbreeding between closely related. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. Pubmed citations 33 downloads 69 views 154 8 authors, including. Book of abstracts the genetics and exploitation of heterosis in crops. Heterosis breeding and inbreeding depression authorstream. Maximum positive heterosis and heterobeltiosis of 4. The estimates of heterosis, heterobetloi ssi and inbreeding depression for pal nt hegi ht, yei dl and its components are presented in table. Inbreeding depression in plants, caused by selfing or crossing among plants with a high degree of relatedness, is a genetic phenomenon that affects quantitative traits. Heterosis and inbreeding depression kana ram kumawat, ravi kumawat and madhu choudhary department of plant breeding and genetics, s. Heterosis and inbreeding depression biotech articles.
Now epigenetic arabidopsis hybrids show that epigenetic diversity and regulation contribute to both. Inbreeding depression is the reduced fitness in a given population as a result of breeding of related individuals. Media in category inbreeding depression the following 7 files are in this category, out of 7 total. Kotiaho,1,2 kari nissinen3 and mikael puurtinen1,4 1 department of biological and environmental science, university of jyvaskyl a, jyv askyl a, finland. The worlds most important grain crop, zea mays exhibits significant heterosis and inbreeding depression, and despite billions of dollars of sales and investments in. A self pollinated species, soybeans are produced as pureline cultivars or blends of inbred lines. Know about inbreeding and inbreeding depression, along with the degrees of depression. Cognitive abilities among inbred and noninbred children. Gene number, function, and mode of action article in conservation biology september 2009 impact factor. The contribution of epigenetic factors to inbreeding depression and heterosis remains elusive. Quantitative genetics of heterosis iowa state university digital. The decline in size and vigour due to inbreeding is illustrated in figure 47.
This article is brought to you for free and open access. Heterosis and outbreeding depression in interpopulation. Inbreeding depression occurs when plants have too small of a population of fellow breeders during pollination. The genetic interpretation of inbreeding depression and. Having to select the best plants from each population and having to make sure there is a large enough population to keep from inbreeding depression can be reason to cause depression among many home gardeners. It causes future generations of plants to be weak as demonstrated by slow growth, poor vigor and disease resistance, along with poor fruit production. This conference proceeding is brought to you for free and open access by the. Hybrid vigor in plants and its relationship to insect pollination pdf. By comparing the phenotypic mean and variance for various co. The genetic basis of reduced inbreeding depression in. Ppt heterosis powerpoint presentation free to view. Inbreeding depression is the loss of viability or function resulting from excess inbreeding, as noted in many populations including plant, dog and human where the negative consequences of inbreeding have been most commonly noted. This phenomenon is observed in several other plant species that are further grouped based on the following four categories.
Inbreeding depression is often the result of a population bottleneck. Pdf inbreeding depression and its evolutionary consequences. Choose from 32 different sets of inbreeding depression flashcards on quizlet. Genomic selection in the near future the technique of genomic selection can play an important role in avoiding the negative aspects of inbreeding. The worlds most important grain crop, zea mays exhibits significant heterosis and inbreeding depression, and despite billions of dollars of sales and. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. In general, the higher the genetic variation or gene pool within a breeding. Inbreeding in animals and plants leads to the formation of weak and lowfertile offspring inbreeding depression. Learn inbreeding depression with free interactive flashcards. The converse or complement to inbreeding depression in which the value d a.
In general, the higher the genetic variation within a breeding population, the less likely it is to suffer from inbreeding depression inbreeding depression seems to be present in most groups of organisms, but. Heterosis and inbreeding depression of epigenetic arabidopsis. Difference between heterosis and inbreeding depression. Inbreeding depression, inbreeding depression and heterosis, genetics. Note that inbredmidparent heterosis is a function of inbreeding depression. Heterosis is defined as the superiority of f1 hybrid over both the parents in terms of yield andor some other characters. Cross pollinated species and species reproducing asexually are highly heterozygous. Inbreeding depression definition at, a free online dictionary with pronunciation, synonyms and translation. Inbreeding depression is normally reduced by immigrants that are heterozygous for deleterious recessive mutations whitlock et al. Inbreeding depression is important in the evolution of outcrossing mating systems and, because intercrossing inbred strains improves yield heterosis, which is important in crop breeding, the genetic basis of these effects has been debated since the early twentieth. Heterosis, inbreeding depression and line performance. The genetic basis of inbreeding depression and of the related phenomenon, heterosis, has been a puzzle for many decades. Expected means and variances among inbred lines and their crosses. Based on recent studies in many species, the authors argue that both.
The worlds most important grain crop, zea mays exhibits significant heterosis and inbreeding depression, and despite billions of. Mutual recognition between a mother and her offspring may also be beneficial to both parties. Agronomy free fulltext evidence for heterosis in italian. Segregation pattern of fertility restoration in icph 2671 and icph 2740 83 4. Heterobeltiosis, relative heterosis, and standard heterosis in cmsbased pigeonpea hybrids at patancheru, 2010 kharif season 70 4. However, outcrossing can reduce mean population fitness if hybridization disrupts coadapted gene complexes or favorable epistatic interactions. Heterosis refers to the phenomenon that progeny of diverse varieties of. Genetic basis of heterosis and inbreeding depression in rice. Inbreeding depression is the reduced biological fitness in a given population as a result of inbreeding, or breeding of related individuals. Winner of the standing ovation award for best powerpoint templates from presentations magazine. Expected means and variances among inbred lines and their crosses c. Recognizing kin is important because it also allows an individual to avoid mating with closely related individuals and thus reduces inbreeding depression in offspring. Heterosis is defined as the superiority of f1 hybrid over both the parents in terms of yield and or some other characters. Even in the absence of inbreeding depression and outbreeding depression, this accumulation of deleterious mutations will lead to a reduction in fitness of about 1% each generation.
Genetic interpretation of inbreeding and outbreeding 623 this paper is an attempt to put the con cepts of inbreeding depression, outbreeding enhancement, and outbreeding depression in a unifying framework and to provide a methodological basis for evaluating the ge netic bases of these phenomena. Average heterosis fl mpmp x 100 where, f, is the mean value of7, and mp is the mean value of two parents involved in the cross. Jan 02, 2012 that is with exception of the maize family, which requires 200 plants to keep from exhibiting inbreeding depression. Combining ability, heterosis and inbreeding depression. A loss of vigor and general health that sometimes characterizes organisms that are the product of inbreeding.
Ppt heterosis powerpoint presentation free to view id. The restoration of phenotypic performance by crossing inbred lines to produce a hybrid is called heterosis. Inbreeding depression for yield and yield related traits in cmsbased pigeonpea hybrids 78 4. The key difference between heterosis and inbreeding depression is that heterosis is the enhancement of traits due to the mixing of genes from two different individuals during outbreeding while inbreeding depression is the reduced biological fitness of offspring due to the increased homozygosity as a result of inbreeding between closely related. Second, populations experiencing bottlenecks or other strong inbreeding should expose deleterious recessive mutations to selection, reducing inbreeding depression 7. Population biological fitness refers to an organisms ability to survive and perpetuate its genetic material. This study aimed at verifying the occurrence of inbreeding depression in crambe progenies originated from selfing, in comparison with open pollination progenies. Two of them, proposed within the first decade after.
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