Standard heterosis when heterosis is estimated over standard commercial hybrid it is called as standard heterosis. Heterosis for some physiomorphological plant traits in. Heterosis refers to the phenomenon that progeny of diverse varieties of a. Exploring the molecular basis of heterosis for plant breeding liu. Heterosis is a phenomenon in which hybrids exhibit superior performance relative to parental phenotypes. 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. 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. Sandeep kumar bangarwa the term heterosis was first used by shull in 1914. Hybrid breeding methods are used in maize, sorghum, rice, sugar beet, onion, spinach, sunflowers, broccoli and to create a more psychoactive. Based on degree of depression, the plant species can be grouped into 4 broad categories.
In 1909, shull found increased grain yields in hybrid. Arabidopsis thaliana has emerged as a leading model species in plant genetics and functional genomics including research on the genetic causes of heterosis. Springer3 1usdaars, plant genetics research unit, and division of plant sciences, university of missouri, columbia, missouri, united states of america, 2usdaars, u. Jul 30, 2017 heterosis is a term used in genetics and breeding and is also known as hybrid vigor. Heterosis for biomassrelated traits in arabidopsis investigated by. However, despite high heterotic values, it is very difficult to produce hybrid okra. Heterosis and combining ability for yield and yield. Heterosis it is defined as the superiority of f 1 hybrid over both the parents in terms of yield or some other characters. Submitted to submitted by derpartment of genetics and plant breeding, college of agriculture, jau, junagadh. Heterosis is used to increase yields, uniformity, and vigor. In breeding depression has been recognised by man for a long time. Heterosis breeding heterosis breeding is here to stay as a potent genetic tool for exploiting the predominantly nonadditive gene action.
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. Click download or read online button to get quantitative genetics and breeding methods book now. Breeding of f1 hybrid cultivars based on heterosis is used in many crops and vegetables. 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. Heterosis, combining ability and components of genetic. It is also referred as useful or economic heterosis. Plant breeding is the art and science of changing the traits of plants in order to produce desired characteristics. The sym posia is held every other year and alternately hosted by the two societies. The study was undertaken with an objective of testing seven inbred lines of maize for their combining ability and to know the gene action involved in inheritance of different traits in maize viz. Quantitative genetics and breeding methods download.
Plant breeding is not so advanced in nepal and need to develop many competitive plant. Pearl millet, fertility restoration, gca, sca, heterosis, correlation coefficient, path coefficient abstract. Among those who would benefit from taking this session are. Pearsons correlation coefficients among yieldrelated traits in the rils a across four environments, the if 2 c populations across three environments, and the midparent heterosis mph dataset. Heterosis is prevalent for multiple traits in diverse maize germplasm sherry a.
Perhaps improved or new disease resistance is required, or increased seed size, or simply increased yield to make the crop profitable. Exploring the molecular basis of heterosis for plant breeding. Hand pollination of tomato for breeding and seed production. Mechanisms of inbreeding depression and heterosis for. A study on heterosis and inbreeding depression in sunflower helianthus annuus l. Opinion paper heterosis, stress, and the environment. Heterosis and inbreeding depression are complementary phenomena, both important to the establishment of breeding strategies, such as conventional hybrids and population breeding. Department of agriculture, agricultural research service, department of genetics, north carolina state university, raleigh, north carolina 27695. In selfpollinated crops, utilization of hybrid vigour is dependent upon a system for economically producing f 1 seeds.
Heterosis and combining ability for yield and yield components were determined in a population derived from half diallel crossing of six cotton genotypes. Breeding vegetable crops download ebook pdf, epub, tuebl. 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. Here, we conducted a systematic survey of the degree of heterosis in arabidopsis thaliana. 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. 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. 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. Genetic dissection of yieldrelated traits and midparent.
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. When two homozygous inbreeds a true breeding line obtained by continuous inbreeding of genetically unlike constituents are crossed together, the resulting hybrids obtained from the crossed seeds are usually robust, vigorous, productive and taller than the either parents. It relies on variation in dna sequences but also on variability in the presence and absence of genes and regulatory elements, or structural polymorphisms sp. Transcriptome analysis of rice root heterosis by rnaseq. Patel assistant professor department of genetics and plant breeding junagadh agricultural university junagadh 362 001 gujarat speaker kamlesh kumar chandel m. The bonus from heterosis should be approximately 5% for production and 10% for mortality, fertility, health and survival. Edwards heterosis is the foundation of modern maize breeding programs. In this article we will discuss about heterosis or hybrid vigour. Heterosis in plant breeding request pdf researchgate.
In addition to the heterosis of aboveground agronomic traits on which most existing studies have focused, root heterosis is also an indispensable component of heterosis in the entire plant and of major importance to plant breeding. Contemporary plant breeding is under pressure to improve crop. Average heterosis it is the heterosis where f 1 is superior to mid parent value. Freezing tolerance is an important trait because it can limit the geographical distribution of plants and their agricultural yield.
In the late 1990s, it was estimated that 65% of the worldwide maize zea mays area was planted as hybrids. After 2010, plant breeding is more science based, business oriented and less art. Heterosis or hybrid vigour is a phenomenon in which hybrid progeny exhibit superior yield and biomass to parental lines and has been used to breed f 1 hybrid cultivars in many crops. Heterosis, inbreeding depression, various theories of. American hereford association craig huffhines kansas city, mo. Therefore, in a search for the basis of heterosis in yield and. Combining ability heterosis maize plant breeding introduction types of hybrids, which exhibit high heterosis when the maize is the worlds most widely grown cereal and is uniformity. Notwithstanding large efforts to study the phenomenon of heterosis in the last decades, the identification of common molecular mechanisms underlying hybrid vigour remain rare. Heterosis, the increase in such characteristics as size, growth rate, fertility, and yield of a hybrid organism over those of its parents. Moench the results revealed that the standard heterosis for fruit yield per plant was maximum in. Heterosis breeding in eggplant solanum melongena l. A free powerpoint ppt presentation displayed as a flash slide show on id.
Plant breeding will be important in developing these significant new characteristics in crops. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. Department of agriculture, agricultural research service, department of genetics, north carolina state university, raleigh, north. Sajjad ahmad1, muhammad sayyar khan2, muhammad siraj swati3, gul sanat shah4 and iftikhar hussain khalil5 abstract ahmad, s. Combining ability and heterosis for yield and component. Heterosis for some physiomorphological plant traits in spring wheat crosses shahzadi mahpara1, muhammad ishaq asif rehmani2, safdar hussain2, javaid iqbal2, muhammad kamran qureshi3, muhammad ahmed shehzad4 and javed shabbir dar5 1. When two homozygous inbreeds a true breeding line obtained by continuous inbreeding of genetically unlike constituents are crossed together, the resulting hybrids obtained from. Breeding crops with a high yield and superior adaptability is vital to maintaining global food security. The latter was estimated in comparison to commercial varieties. Phase 1 the breeder identifies the needs of the farmers and the deficiencies in the current varieties.
Heterosis and heterobeltiosis occurred in varying degrees. Heterotic plants will probably have slightly different distributions of cell types. Heterosis most of the maize varieties grown in the u. The flowering gene single flower truss drives heterosis for. Transcriptomic and proteomic analysis of heterosis various transcriptomic es have been carried out to explore the gene expression changes between hybrid analys and its parents to correlate the changes to heterosis. Despite such an extensive use in agriculture, the underlying mechanisms of heterosis are still poorly understood. Hand pollination is a technique that is used for breeding new tomato varieties with desirable characteristics such as plant vigor, disease resistance, and uniform fruit quality and plant growth. An effort has been made in the present paper to critically assess the level of success and future strategies in the development and adoption of hybrid technology in selected field crops under three categories. Shull 1952 coined the term heterosis and defined it as. Plant and animal breeders exploit heterosis by mating two different purebred lines that have certain desirable traits. Pdf estimation of heterosis and combining abilities of us. In this study, we explored heterosis for earweight ewrelated traits using a north carolina experiment iii design design iii population derived from the elite maize hybrid zhengdan 958.
The scientific method consists of observation, formulation of hypothesis, experimentation and conclusion either to accept or reject the hypothesis. Heterobeltiosis when heterosis is estimated over better parent it is called as heterobeltiosis. One of the fascinating techniques of plant breeding the heterosis, know about the hypothesis and application in plant breeding. Twenty five germplasm lines were crossed with three cytoplasmic male sterile lines of a1 cytoplasm, namely, hms 41a, hms 42a and icma 97444 in line x tester fashion to produce 75 hybrids. Despite its importance in maize production, we know surprisingly little about the genetic basis of heterosis. Innovative male sterility system and exploitation of hybrid vigour in crop plants i. 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. High heterosis values can be obtained using hybrid okra seeds. Khalil5 a study on heterosis and inbreeding depression in sunflower. Pdf heterosis refers to the phenomenon that progeny of diverse varieties of a species or crosses between species exhibit greater biomass, speed of. Heterosis is prevalent for multiple traits in diverse maize. Quantitative genetics and selection in plant breeding.
Science is the knowledge gathered through scientific method. Genotypebyenvironment interactions affecting heterosis in. Heterosis and combining ability in a diallel cross of. Natural genetic diversity within and among species is the basis of most plant breeding programs. Formation of heterotic pools and understanding relationship.
Heterosis is a term used in genetics and breeding and is also known as hybrid vigor. This was interpreted as heterosis in cell number due to an enhancement of the rate of cell division. Studies on heterosis in okra abelmoschus esculentus l. The converse or complement to inbreeding depression in which the value d a inbreeding can result in loss of vigor, size, etc. Heterosis is an additional gain above the average genetic level of the two parent breeds. 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. Objectives communicate and discuss the discipline of practical plant breeding and its importance to us agriculture and food systems.
Heterosis plays a decisive role in maize production worldwide, but its genetic basis remains unclear. This method can be used for conserving heterosis in vegetatively propagated crops such as sugarcane, potato, sweet potato, banana etc. Importance of plant breeding, cytological principles of plant breeding, heterosis, inbreeding and its consequences or applications, selfincompatibility in plants, cytoplasmic male sterility, breeding. Quantitative trait loci qtl analysis was conducted based on phenotypic data collected from five. These observations provide strong support for the model that trueoverdominant genes exist and can drive yield heterosis. Recent research on the mechanism of heterosis is important for crop. More branches per panicle and more grains per branch.
New technologies on multiple scales are reengineering traditional plant breeding to meet. Predicting arabidopsis freezing tolerance and heterosis in. 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. Heterosis definition types of heterosis heterosis in.
Genomic architecture of heterosis for yield traits in rice. The objectives of this project are to characterize the extent of sp between and. Plant breeding consists of four main phases all of which run concurrently in an established program. Click download or read online button to get breeding vegetable crops book now. Heterosis breeding and inbreeding depression authorstream. Insights into the genomic architecture of heterosis for grain yield in rice are presented, and further mapping of grain yield loci resolves candidate genes that could be useful for breeding. Three classical models have served as the foundation for dissecting heterosis into genetic and molecular components1,3,12. P7 f1 crosses significantly surpassed the highest parental genotype for number of branches per plant, flower set, pod set, number of pods per plant, maturity time, 100seed weight and seed yield per plant. Heterosis, or hybrid vigor, is one of the most important tools in plant breeding and has previously been demonstrated for plant freezing tolerance. A study was conducted to assess the combining ability and heterosis of 14 parental lines by developing 91 single cross hybrids following half diallel mating design in maize at the department of genetics and plant breeding, uas, bengaluru.
Structural polymorphisms as causes of heterosis in populus. Climate change plants use energy from the sun to convert water from the soil and co 2 from the air into sugars and oxygen. Completion of selfpollinated plant breeding for professionals, genetic resources for plant breeding, and outcrossing in plant breeding is recommended. Studies on heterosis and combining ability in bittergourd. In this perspective, we consider that it might be useful to the field to abandon these. One of the reasons for using such wide crosses is to obtain heterosis. Heterosis is commercially exploited in rapeseed brassica napus l. Department of plant breeding and genetics, ghazi university, d. Plant breeding is considered as the current phase of crop evolution.
Mar 28, 2014 thus, plant breeding is purely science with very little art involved. Various models have been posited to explain heterosis, including dominance, overdominance, and pseudooverdominance. Lacey livestock john and mark lacey paso robles and independence. Frontiers identification of heterosisassociated stable. Pdf hybrid wheat offers promises to break the yield stagnation in global wheat productivity due to heterosis. This explanation of heterosis has been an undercurrent in ongoing discussions from 1936 east, 1936 to the present time e.
In modifying amd developing postgraduate course in genetics and plant breeding, emphasis has been given to keep a balance among major components like basic genetics, cytogenetics, plant breeding, quantitative genetics, molecular biology and biotechnology. Hybrid vigour, or heterosis, has been of tremendous importance in agriculture for the improvement of both crops and livestock. Impacts of crossbreeding american hereford association. Since then, heterosis has been widely utilized in crop breeding, ly in mespeciala ize. The fixation of heterosis by apomixis is common in citrus fruits, black berries, roses, blue grasses and many other flowering plants. Amaryl lids to download pdf you need some things, like my website and the name of the file. Plant breeding and genetics all semester notes pdf file. Ppt heterosis powerpoint presentation free to view id. Impacts of crossbreeding on profitability in vertically coordinated beef industry marketing systems final report david a. Improving plants using hybrid vigor module agronomy and. In addition to conventional plant breeding, anther culture, shoot tip culture, mutation breeding and marker assisted selection have been increasingly applied to breed the varieties. Heterosis, inbreeding depression, various theories of heterosis.