Given the numerous advantages of arabidopsis thaliana as a model species. Heterosis definition of heterosis by the free dictionary. To discuss the utilisation of heterosis in plant breeding it is necessary to consider its genetic basis. 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. Heterosis is a multigenic complex trait and can be extrapolated as the sum total of many physiological and phenotypic traits. The increased heterosis for hi under increasing plant density was associated with a greater planttoplant variability and a higher threshold plant dry matter for hi at maturity in the inbred. Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. Heterosis, the increase in such characteristics as size, growth rate, fertility, and yield of a hybrid organism over those of its parents. Despite such an extensive use in agriculture, the underlying mechanisms of heterosis are still poorly understood. Jun 23, 2003 heterosis is of utmost economic importance in plant breeding. Darwin 1876 also reported that inbreeding in plants results in deterioration of vigour and the crossing in hybrid vigour.
In recent years, unlocking the genetic diversity of species has provided insights into the genomics of rice domestication, heterosis, and complex traits. Quantitative trait locus analysis of heterosis for plant. However, leng reports that row number is affected in widely different degrees by heterosis, and that number of kernels per row ear length is the only primary yield component in which large positive effects of. The firstgeneration offspring generally show, in greater measure, the desired characteristics of both parents. Heterosis has been widely used in agriculture to increase yield and to broaden adaptability of hybrid varieties and is applied to an increasing number of crop species. Exploring the molecular basis of heterosis for plant breeding. Parental dna methylation states are associated with. Highlight epigenetic variations in plant hybrids and their potential roles in heterosis guangming he a, hang he a, xing wang deng a,b, apekingyale joint center for plant molecular genetics and agrobiotechnology, state key laboratory of protein and plant gene research, school of life sciences, peking university, beijing 100871, china. Here, we characterize the genomic architecture of heterosis in arabidopsis that have not undergone domestication and identify hundreds of. Hybrid vigour, or heterosis, has been of tremendous importance in agriculture for the improvement of both crops and livestock. This theory is based on the assumption that hybrid vigour resulting from heterosis hybridization brings the dominant, favorable genes together. Exploring the molecular basis of heterosis for plant breeding liu. Giora benari, uri lavi, in plant biotechnology and agriculture, 2012.
Hybrid vigour has been exploited in both self as well as cross pollinated species. In this article we will discuss about heterosis or hybrid vigour. Jul 25, 2017 heterosis, the phenotypic superiority of a hybrid over its parents, has been extensively exploited in agriculture to improve biomass and yield. Shull 1952 coined the term heterosis and defined it as. Institute of plant breeding, seed science and population genetics, university of hohenheim, fruwirthstra e 21, d70599 stuttgart. When these species are subjected to selfing or inbreeding they show severe reduction in vigour and fertility.
Hybrid vigor heterosis michael gore lecture notes tucson winter institute version 18 jan 20. Owing to heterosis hybrid vigor in plants, these hybrids often have superior agricultural performances in yield or disease resistance succeeding. Exploring the molecular basis of heterosis for plant. Heterosis can be defend as the superiority of f hybrid over both the parents in terms of yield and some other character. Shull and easts rediscovery of heterosis in 1906 paved the way for the introduction of the first maize hybrid varieties in the us market in early 1930. There are many phenotypic components to total yield, which can be viewed as the ultimate output of the plant system as a whole. A free powerpoint ppt presentation displayed as a flash slide show on id. Heterosis is of utmost economic importance in plant breeding. Genomic architecture of biomass heterosis in arabidopsis.
The converse or complement to inbreeding depression in which the value d a inbreeding can result in loss of vigor, size, etc. Parental dna methylation states are associated with heterosisinepigenetichybrids1open kathrin lauss,a,2 rene wardenaar,b,2 rurika oka,a marieke h. Heterosis for biomass yield and related traits in five hybrids. Here, we conducted a systematic survey of the degree of heterosis in arabidopsis thaliana. Difference between heterosis and hybrid vigour compare the. Cross pollinated species and species reproducing asexually are highly heterozygous.
In the present study, we carried out dynamic analysis for plant height and its heterosis by quantitative trait loci qtl mapping at multiple developmental stages using two recombinant inbred lines. Heterosis breeding in eggplant solanum melongena l. The phenomenon of heterosis was first described by darwin as having a positive effect on plant traits, as displayed by crossfertilized over selffertilized progenies in the vegetable kingdom. Sandeep kumar bangarwa the term heterosis was first used by shull in 1914. Genotypebyenvironment interactions affecting heterosis. However in both autogamous or allogamous plants it is difficult to exclude a role of marginal overdominance which could. Pdf heterosis refers to the phenomenon that progeny of diverse varieties of a species or. One of the fascinating techniques of plant breeding the heterosis, know about the hypothesis and application in plant breeding. It is likely that a common biological mechanism underlying heterosis is existed in a wide variety of different species. Likewise, the intent of the detection and exploitation of heterosis section was to examine how het erosis can be manipulated and utilized in practice.
Progress toward understanding heterosis in crop plants annual. Notwithstanding large efforts to study the phenomenon of heterosis in the last decades, the identification of common molecular mechanisms underlying hybrid vigour remain rare. Main effect qtl with dominance determines heterosis for. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. Ppt heterosis powerpoint presentation free to view id.
Heterosis performance in industrial and yield components of sweet corn. Department of agriculture, agricultural research service, department of genetics, north carolina state university, raleigh, north. Heterosis definition types of heterosis heterosis in. Although heterosis, or hybrid vigor, is widely exploited in agriculture, a complete description of its. Iaa7 contributes to improved plant architecture and yield heterosis in rapeseed haitao li1, juanjuan li1, jurong song1, bo zhao1, chaocheng guo1, bo wang1, qinghua zhang1, jing wang1.
Freezing tolerance is an important trait because it can limit the geographical distribution of plants and their agricultural yield. We performed a systematic survey of the extent and degree of heterosis for dry biomass in 63 arabidopsis accessions crossed to three reference lines col0, c24, and nd. Increasing plant density did not affect heterosis for dry matter at maturity, but caused an increase in heterosis for grain yield and hi. In my opinion, hybrid corn is the most far reaching development in applied biology in this quarter century mangelsdorf, 1951. Edwards heterosis is the foundation of modern maize breeding programs.
Abstract heterosis or hybrid vigor is a natural phenomenon whereby hybrid offspring of genetically diverse individuals display improved. While the practical application of heterosis in plant breeding is quite successful in many crops through the development of hybrid varieties, the basic understanding of the phenomenon is not very advanced. This concept does not on the surface account for why hybrids typically show positive heterosis rather than random positive or negative effects. Department of agriculture, agricultural research service, department of genetics, north carolina state university, raleigh, north carolina 27695. Heterosis is a common phenomenon in maize, rice and other species 6.
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. These effects can be due to mendelian or nonmendelian inheritance. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. Heterosis dominated the thinking of plant and animal geneticists in the. Physiological basis of heterosis for nitrogen use efficiency. Keurentjes,c maike stam,a,3 and frank johannese,f,3 auniversity of amsterdam, swammerdam institute for life sciences, 1098xh amsterdam, the netherlands.
Plant height ph and ear height eh are two important agronomic traits in maize selection breeding. Oct 23, 2017 heterosis is a result of two main phenomena. Heterosis for biomass yield and related traits in five. In this study we measured 25 traits in a set of 47 maize hybrids and their inbred parents grown in 16 different environments with varying levels of average productivity. Keurentjes,c maike stam,a,3 and frank johannese,f,3 auniversity of amsterdam, swammerdam institute for life sciences, 1098xh amsterdam, the netherlands buniversity of groningen, groningen. Breaking yield barriers for 2050 phillips 2010 crop sci. Heterosis may be defined as the superiority of an f 1, hybrid over both its parents in terms of yield or 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. L george harrison shull2 princeton university, princeton, new jersey received april 21, 1948 i t is not my purpose in this paper to present or discuss the actual basic causes or the fundamental mechanisms which bring about the increased size, the excessive kinetic energy, the increased productiveness, resistance to.
Difference between heterosis and hybrid vigour compare. Genetic analysis of heterosis although the genetic basis for heterosis has been studied for over a century hypotheses have been and several. Feb 28, 2017 one of the fascinating techniques of plant breeding the heterosis, know about the hypothesis and application in plant breeding. Here, hochholdinger and baldauf provide an overview of this fascinating biological phenomenon and what is known about the underlying genetics and mechanisms. Heterosis, the phenotypic superiority of a hybrid over its parents, has been extensively exploited in agriculture to improve biomass and yield. It was suggested that heterosis of traits related to plant growth is primarily conditioned by proliferation, hence an increase in cell number, but not cell size. F1 hybrid exhibit significant heterosis for ph and eh as compared to their parental inbred lines. Genome sequencing and analysis of numerous wild rice and asian cultivated rice accessions have enabled the identification of genomewide signatures of. However, leng reports that row number is affected in widely different degrees by heterosis, and that number of kernels per row ear length is the only primary yield component in which large positive effects of heterosis are manifested consistently 20. 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. Abstract heterosis, or hybrid vigor, is one of the most important tools in plant breeding and has previously been demonstrated for plant freezing tolerance. Heterosis, also called hybrid vigour, the increase in such characteristics as size, growth rate, fertility, and yield of a hybrid organism over those of its parents. Heterosis may be defined as the superiority of an f 1, hybrid over both its parents in terms of yield or some other character heterosis, or hybrid vigour, describes the superior performance of heterozygous hybrid individuals compared with their homozygous parental inbred lines. Despite its great agricultural importance, the genetic components underlying heterosis remain largely unclear.
Various models have been posited to explain heterosis, including dominance, overdominance, and pseudooverdominance. Genomic architecture of biomass heterosis in arabidopsis pnas. A plant breeding phenomena that we very successful exploit commercially, the biological basis of which remains poorly understood. This phenomenon involves the fact that maximizing diverse genomes in a polyploid results in increasingly greater magnitudes of heterosis as a general rule. King2 and kede liu1 1national key laboratory of crop genetic improvement, huazhong agricultural university, wuhan 430070, china. Gains and provocations ashish kumar 1,y, vinay sharma 2,y, bharat taindu jain 3 and prashant kaushik 4,5, 1 national agrifood biotechnology institute nabi, punjab 140308, india. Plant and animal breeders exploit heterosis by mating two different purebred lines that have certain desirable traits.
Heterosis or hybrid vigour is the superiority of a hybrid offspring over the average of both its genetically distinct parents. Abstract understanding the genetic bases underlying heterosis is a major issue in maize zea mays l. Heterosis is the superior performance of f 1 hybrids relative to the midparent value mpv or to the better parent. Heterosis can be defend as the superiority of f hybrid over both the parents in terms of yield and some other character or.
Heterosis in plant breeding request pdf researchgate. Plant height, which shows dynamic development and heterosis, is a major trait affecting plant architecture and has an indirect influence on economic yield related to biological yield in cotton. This increased productivity or superiority over the parents is known as heterosis or hybrid vigor or. Hybrid vigor is defined by mechanisms such as dominant. The developmental program of hybrids is not dramatically altered, so a specific type of. Heterosis is defined as the superiority of f1 hybrid over both the parents in terms of yield andor some other characters. The intent of the mechanisms of heterosis section was to examine the underlying genetics and biology of heterosis.
Heterosis refers to the superior phenotypes observed in hybrids relative to their inbred parents with respect to traits such as growth rate, reproductive success, and yield. Jul 09, 2010 one must keep in mind that the changes that occur in heterosis concerning plant growth are basically differences in cell number with regard to most plant characteristics. Heterosis dominated the thinking of plant and animal geneticists in the 1940s and 1950s as evidenced by the now classic book entitled heterosis edited by john w. Oct 01, 2016 plant height, which shows dynamic development and heterosis, is a major trait affecting plant architecture and has an indirect influence on economic yield related to biological yield in cotton. Heterosis breeding and inbreeding depression authorstream. 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. Given the numerous advantages of arabidopsis thaliana as a. We generated 450 hybrids by manual crosses between 415 inbred. The environment can influence heterosis, the phenomena in which the offspring of two inbred parents exhibits phenotypic performance beyond the inbred parents for specific traits. 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. Assessment of heterosis in two arabidopsis thaliana common.
Inbred plants may grow somewhat slower than the corresponding hybrids, but earliness and lateness is an ordinary quantitative and not heterotic character, with. Heterosis was discovered in maize about a century ago and has subsequently been found to occur in. To understand the genetic basis of heterosis controlling ph and eh, we conducted quantitative trait locus qtl analysis using a recombinant inbreed line ril based design iii. In the noncrop plant arabidopsis, heterosis is mainly reflected in seedling biomass, although an accurate assessment of hybrid vigor for reproductive traits is still lacking 24, 25, 26. The genomics of oryza species provides insights into rice.
In cross a, seed weight revealed heterosis while in cross b plant characters like seed weight, flag leaf area, harvest index and spike length showed heterosis mohamed 2014. Sep 24, 2018 for instance, the levels of heterosis for plant height and grain yield are often negatively correlated in maize. Plant heterosis shouqian feng, xiaoliu chen, shujing wu, xuesen chen. Plant height, biomass, harvest index, number of primary branches, number of pods per plant, number of seeds per plant, 100seed weight and seed yield were recorded for each plant 10 observation. Production of hybrids of seedpropagated horticultural crops is one of the most successful plant breeding techniques because it exploits heterosis, promotes homogeneity, and is a way for commercial breeders to control their products without the necessity for. Iaa7 contributes to improved plant architecture and yield heterosis in rapeseed haitao li1, juanjuan li1, jurong song1, bo zhao1, chaocheng guo1, bo wang1, qinghua zhang1, jing wang1, graham j.
In this perspective, we consider that it might be useful to the field to abandon these. Gowen and published by iowa state university press. Heterosis, also known as hybrid vigor, is a wellknown phenomenon whereby hybrid offspring resulting from cross pollination exhibit greater vigor than either parent. Heterosis or hybrid vigor results in a hybrids phenotypic superiority over its founder parents for quantitative and qualitative traits. Davenport, bruce and keable, and pellew proposed this theory in 1910. Selection of parents for the generation of heterosis. However, its underlying molecular causes are still unknown. Here, we characterize the genomic architecture of heterosis in arabidopsis that have not undergone domestication and identify hundreds. Thus, the studies of gene expression to date on the whole are ambiguous as to whether any observed changes are correlative, causative, or predictive of heterosis. The widespread occurrence of heterosis in the model plant arabidopsis.
Progressive heterosis is a phenomenon in polyploid plants that is critical to developing a viable model of heterosis. Highlight epigenetic variations in plant hybrids and their potential roles in heterosis guangming he a, hang he a, xing wang deng a,b, apekingyale joint center for plant molecular genetics and agrobiotechnology, state key laboratory of protein and plant gene research, school of life. Parental dna methylation states are associated with heterosis. The expression of heterosis is restricted to the hybrid individual f1 generation and it dissipates in the advanced generations or in the progenies derived from it due to segregation and recombination which disturb the original heterotic combination of genes. Despite its importance in maize production, we know surprisingly little about the genetic basis of heterosis. Ppt heterosis powerpoint presentation free to view. When the heterosis is estimated over the mid parent, i.