Ppt heterosis powerpoint presentation free to view. Combining ability is a measure for selecting elite parents that make the highest contributions to hybrid performance. Earley california state university, chico college of agriculture cooperators. Heterosis has been phenotypically expressed in numer. Classical and molecular concepts of heterosis springerlink. In search of the molecular basis of heterosis plant cell. Plant and animal breeders exploit heterosis by mating two different purebred lines that have certain desirable traits. Consequently, breeding strategies led to establishment of heterotic group for hybrid breeding. If true, it should not be possible to obtain an inbred that performs equally as well as the best hybrid bernardo 2002 breeding for quantitative traits in plants pp 243246. Plant breeding and genetics all semester notes pdf file. Heterosis or hybrid vigor, on the other hand, is the tendency of outbred strains to exceed both inbred parents in fitness. M82 plants and their sugar production was higher, resulting in heterosis for the multiplicative phenotype of brixyield. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.
Various models have been posited to explain heterosis, including dominance, overdominance, and pseudooverdominance. Heterosis and combining ability for yield and yield. Progress toward understanding heterosis in crop plants. Heterosis or hybrid vigor describes the improved performance of the first filial f 1 generation over their inbred parents in both quantitative and qualitative aspects shull, 1908. Impacts of crossbreeding on profitability in vertically.
Heterosis is due to masking of deleterious recessive alleles by dominant alleles 4. I hold it to be absolutely necessary to distinguish sharply between the facts and the theory derived from them shull 1948. It appears that there is not a single, simple explanation for heterosis. Today, the concept of heterosis is widely used in plant and animal breeding. Shull 1952 coined the term heterosis and defined it as. Types of heterosis there are three main types of heterosis. Inbreeding depression loss or decrease in vigor due to inbreeding. Specifi c hybrids were used to determine if heterosis existed among individual plants from. However, the genetic bases of combining ability and how they contributed to heterosis is seldomly known. Concepts and breeding of heterosis in crop plants, the third joint plant breeding symposia, was held on sunday, 3 november 1996 in indianapolis at the asacssasssa national meetings.
Production of f 1 or f 2 hybrid cotton seed for commercial use by farmers in the u. The flowering gene single flower truss drives heterosis for. Heterosis is prevalent for multiple traits in diverse maize germplasm sherry a. Tesso 2 1department of agronomy dan horticulture, faculty of agriculture, bogor agricultural university, bogor, indonesia. Selective breeding of plants and animals, including hybridization, began long before there was an understanding of underlying scientific principles. Heterosis or hybrid vigor results in a hybrids phenotypic superiority over its founder parents for quantitative and qualitative traits. Head quality often improves as some defects of the parent lines are recessive.
Population hybrids were used to determine if heterosis exists among plants from diff erent populations and to determine of heterotic groups existed among the tested populations. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. Analysis of the total yield shows that heterosis exists both for head number and head weight. Heterosis, the increase in such characteristics as size, growth rate, fertility, and yield of a hybrid organism over those of its parents. Heterotic plants will probably have slightly different distributions of. Progress toward understanding heterosis in crop plants annual. Thus, sftdependent heterosis is extremely robust and shows substantial.
N2 although heterosis, or hybrid vigor, is widely exploited in agriculture, a complete description of its molecular underpinnings has remained elusive despite extensive investigation. The flowering gene single flower truss drives heterosis. However, one of the most powerful and broadly applicable hypotheses for heterosis is the dominance theory. In both traits, the embryos contributed markedly and significantly.
Heterosis is prevalent for multiple traits in diverse maize. On the basis of his experiments beal 18771882 concluded that f 1 hybrids yield as much as 40 percent more of the parental varieties from subsequent studies on intervarietal crosses in maize, it was observed that some of the hybrids show heterosis. Inbreeding depression results due to fixation of unfavourable recessive genes in f2. Heterosis definition types of heterosis heterosis in. Impacts of crossbreeding on profitability in vertically coordinated beef industry marketing systems final report david a. Inbreeding may or may not lead to inbreeding depression, which is a reduction in the fitness in the offspring produced by inbred matings. Consequently, in a search for the basis of the advantage of heterosis in yield and adaptation, this analysis bypasses the genetics and genomics of heterosis and looks for answers in the phenomics of heterosis. The topic of heterosis grew out of discus sions between committee members who had organized the previous symposia. To elucidate seedling growth heterosis, we conducted comparative transcriptomic analyses between the two hybrids and their. Heterosis breeding and inbreeding depression authorstream. The contribution of epigenetic factors to inbreeding depression and heterosis remains elusive.
Heterosis can be obtained in plants, animals, and microorganisms for various economically important characters. Heterosis is defined as the superiority of f 1 hybrids in their performance over their parents 19, 20 and has been attributed to three different genetic hypotheses. Sep 09, 2019 heterosis is defined as the superiority of f 1 hybrids in their performance over their parents 19, 20 and has been attributed to three different genetic hypotheses. Genotypebyenvironment interactions affecting heterosis in. Heterosis most of the maize varieties grown in the u. Two or more loci are needed because the value of a heterozygote at a single locus da does not exceed the value of the superior parent. The phenomenon of heterosis can be explained on the basis of the causes. Notwithstanding large efforts to study the phenomenon of heterosis in the last decades, the identification of common molecular mechanisms underlying hybrid vigour remain rare. Despite such an extensive use in agriculture, the underlying mechanisms of heterosis are still poorly understood. A free powerpoint ppt presentation displayed as a flash slide show on id. Since the 20th century, the heterosis breeding technology has been widely applied in cucumber, tomato, corn and other horticultural crops due to the merits shown by the f1. Heterosis, also known as hybrid vigor, is a phenomenon where an organism has greater vigor than its distantly related parents. After maize hybrid was first utilized in field on a large scale in usa in 1930s, heterosis of other crops such as rice, sorghum, rape, and vegetable etc began to be widely used in production, and had made great achievements in crop breeding by the end of last century, mainly contributed to notable increasing of crop yield.
Despite its importance in maize production, we know surprisingly little about the genetic basis of heterosis. Ppt heterosis powerpoint presentation free to download. Heterosis is prevalent for multiple traits in diverse. Breeding rubber tree seedling with growth heterosis is vital for natural rubber production. Concepts and breeding of heterosis in crop plants proceedings of the plant breeding symposium sponsored by the crop science society of america and the american society of horticultural science, 3. However in both autogamous or allogamous plants it is difficult to exclude a role of marginal overdominance which could. Shull proposed the term heterosis for the phenomenon that the physiological vigor of an organism. Heterosis refers to the phenomenon that progeny of diverse varieties of a. Lacey livestock john and mark lacey paso robles and independence. Seedling emergence was faster in the hybrid and potence ratios indicated dominance for increased leaf number, area and mass, and stem mass. Heterosis is formed by crossing different strains or varieties. Melchinger introduction during an invited lecture in gottingen, germany, in 1914 the american geneticist g. Despite these successes, plant breeders and geneticists are not. Heterosis for some physiomorphological plant traits in.
The converse or complement to inbreeding depression in which the value d a inbreeding can result in loss of vigor, size, etc. Transcriptome and metabolite profiling reveal novel. Edwards heterosis is the foundation of modern maize breeding programs. N2 although heterosis, or hybrid vigor, is widely exploited in agriculture, a complete description of its molecular underpinnings. If true, it should be possible to obtain an inbred that performs equally as well as the best hybrid. It is generally agreed that hybrid vigour describes only superiority of the hybrid over the parents while heterosis describes the other situation as well i. Instead, it is likely that heterosis arises in crosses between genetically distinct individuals as a result of a diversity of mechanisms. Although heterosis, or hybrid vigor, is widely exploited in agriculture. Specific loci for heterosis reported in previous studies corroborated each one of these hypotheses 2638. Plant breeding and genetics all semester notes pdf, principles of genetics pdf, introductory genetics see pdf, principles of plant breeding pdf, introductory plant breeding, principle of genetics and cytogenetics, principles of plant biotechnology pdf, fundamentals of food technology pdf, breeding of crops pdf, principles of genetics, history, mendels laws and exceptions, types of gene.
Our new crystalgraphics chart and diagram slides for powerpoint is a collection of over impressively designed datadriven chart and editable diagram s guaranteed to impress any audience. Here, we conducted a systematic survey of the degree of heterosis in arabidopsis thaliana. Heterosis can be defend as the superiority of f hybrid over both the parents in terms of yield and some other character. In cross fertilized plants in which the phenomenon of heterosis is very important, such as maize, it appears that a great part can be explained by the mutation load. In crops, heterosis must be considered within the context of the genomic impacts of prior. Impacts of crossbreeding american hereford association. Overdominance heterosis was displayed for root mass, leading to slight heterosis for total plant mass. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. The phenomenon of heterosis was first described by darwin as having a positive effect on plant traits, as displayed by crossfertilized over selffertilized. Crossing of the two parental forms brings in an accidental, excessive and unadaptable expression of temporary vigour and vegetative overgrowth.
The metabolicphysiological expression of heterosis in plants. Although heterosis, or hybrid vigor, is widely exploited in agriculture, a complete description of its molecular underpinnings has remained elusive despite extensive investigation. This phenomenon has been exploited extensively in crop production and has been a powerful force in the evolution of plants. Heterosis refers to the super performance of a hybrid exhibiting increased biomass, size, yield, growth rateor. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. Pdf heterosis, or hybrid vigor, occurs when hybrid performance exceeds that of either parent. Heterosis, or hybrid vigor, refers to the phenomenon that progeny of diverse inbred varieties exhibit greater biomass, speed of development, and fertility than the better of the two parents. Pdf heterosis refers to the phenomenon that progeny of diverse varieties of a species or. Zerihun desalegn1, ngamchuen ratanadilok2, rungsarid kaveeta2, pradit pongtongkam3 and ananchai kuantham4 abstract heterosis and combining ability for yield and yield components were determined in a population derived from half diallel crossing of. Transcriptomic analyses reveal molecular mechanisms. Hybrid vigour, or heterosis, has been of tremendous importance in agriculture for the improvement of both crops and livestock. Rice is one of the most important model crop plants whose heterosis has been wellexploited in commercial hybrid seed production via a variety of types of malesterile lines.
Cross pollination is generally much improved with this approach but the male plants harvested in the blend tend to depress the overall hybrid performance holland, 1999. Winner of the standing ovation award for best powerpoint templates from presentations magazine. Heterosis can be defend as the superiority of f hybrid over both the parents in terms of yield and some other character or. Genetic dissection of yieldrelated traits and midparent.
One of the reasons for using such wide crosses is to obtain heterosis. Transcriptome and metabolite profiling reveal novel insights. Assessment of heterosis in two arabidopsis thaliana common. Opinion paper heterosis, stress, and the environment. Hybrid vigor is defined by mechanisms such as dominant. Genetics of heterosis dominance hypothesis masking of unfavorable recessive alleles in a heterozygote. Katyal, director, naarm, hyderabad, who hosted the workshops on genetics and plant breeding, and seed. Heterosis is a multigenic complex trait and can be extrapolated as the sum total of many physiological and phenotypic traits. Specific changes in total and mitochondrial proteomes are. Jan 20, 2014 types of heterosis there are three main types of heterosis. Joseph koelreuter 1776 described that some plant hybrids displayed superior. To date, three competing but nonmutually exclusive genetic models have been invoked to explain heterosis in both plants and animals, including epistasis, overdominance and dominance. Heterosis is observed in almost every crop species studied, the application of this phenomenon for its commercial exploitation depends on the expression of the degree of heterosis. Springer3 1usdaars, plant genetics research unit, and division of plant sciences, university of missouri, columbia, missouri, united states of america, 2usdaars, u.
Darwin 1876 also reported that inbreeding in plants results in deterioration of vigour and the crossing in hybrid vigour. Nonlinear phenotypic variation uncovers the emergence of heterosis. Ppt heterosis powerpoint presentation free to view id. Heterosis is observed in almost every crop species studied, the application of this phenomenon for its commercial exploitation depends on. More branches per panicle and more grains per branch. Heterotic responses are usually quantified in adult plants by measuring differences in biomass, yield, growth rate, flowering time and other traits flint. The offspring of a f1 female will benefit from maternal heterosis 3.
Dissecting combining ability effect in a rice nciiiii. It is the prerequisites for effectively utilizing growth heterosis to elucidate its molecular mechanisms, but the molecular mechanisms remain poorly understood in rubber tree. Heterosis, stress, and the environment page 3 of 9. Heterosis refers to the phenomenon in which hybrid progeny show superior performance relative to their parents.
Genomewide proteomic profiling reveals the role of. The intent was to produce a more uniform, acceptable product for the consumer. Heterosis has been observed in many plant and animal species 1, 2. Heterosis is directly proportional to the number of dominant genes contributed by each parent 18. It focuses on complementation of deleterious polymorphisms in heterotic individuals. Thus heterosis is very important in corn, a normally crosspollinated plant, but not in the tomato, a normally selfpollinated plant 32. Now epigenetic arabidopsis hybrids show that epigenetic diversity and regulation contribute to both. To discuss the utilisation of heterosis in plant breeding it is necessary to consider its genetic basis. Structural polymorphisms as causes of heterosis in populus.
American hereford association craig huffhines kansas city, mo. Heterosis refers to the phenomenon that progeny of diverse varieties of a species or crosses between species exhibit greater biomass, speed of development, and fertility than both parents. Heterosis refers to the super performance of a hybrid exhibiting increased biomass, size, yield, growth rateor fertility relative to its parents 1. Heterosis of sorghum hybrid developed from local and introduced lines erin puspita rini 1, trikoesoemaningtyas 1, desta wirnas 1, didy sopandie 1, tesfaye t.
Heterosis, or hybrid vigor, which is widely used in agricultural production practice, refers to the phenomenon in which a hybrid progeny has a greater biomass and higher yield and quality than the parents. Now epigenetic arabidopsis hybrids show that epigenetic diversity and. Heterosis and combining ability for yield and yield components of cotton gossypium hirsutum l. Superiority of dominant alleles over recessive alleles 3. Based on a specific diallel mating scheme, heterosis was assessed extremely early, when the faba bean individuals existed as embryo as mature seed. A convincing example is that successful utilization of heterosis has dramatically increased corn production over the last century. Heterosis for some physiomorphological plant traits in spring wheat crosses. This increased productivity or superiority over the parents is known as heterosis or hybrid vigor or. Heterosis is important for several useful attributes. Heterosis is retained in the breeding of crossbred animal and is related to the probability of alleles from different parental lines joining together. In plants, the phenomenon is common both in cross as well as in selfpollinated crops.
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