Heterosis is defined as the superiority of f1 hybrid over both the parents in terms of yield andor some other characters. Genomic architecture of heterosis for yield traits in rice. 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. The sym posia is held every other year and alternately hosted by the two societies. General combining ability gca is mainly due to the additive genetic effects in the evaluation of parents, while specific combining ability sca reflects the non. Estimation of heterosis over better parent heterobeltiosis. Combining ability and heterosis for yield and component. 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 and combining ability analysis in cms hybrid. To discuss the utilisation of heterosis in plant breeding it is necessary to. Heterosis definition types of heterosis heterosis in.
Heterosis is an additional gain above the average genetic level of the two parent breeds. 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. 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. Combining ability and heterosis for yield and related. Breeding crops with a high yield and superior adaptability is vital to maintaining global food security.
In this perspective, we consider that it might be useful to the field to abandon these. Exploitation of heterosis is considered to be one of the outstanding achievements of plant breeding. Shull 1952 coined the term heterosis and defined it as. Heterosis is a term used in genetics and breeding and is also known as hybrid vigor. Today, heterosis is extensively exploited without detailed knowledge of the underlying molecular principles. Heterosis in maize affects mainly the following characters.
Organizational aspects of a plant breeding programme. The contribution 76 of various potential molecular mechanisms to heterosis remains one of the most intriguing and 77 powerful enigmas in plant biology birchler et al. 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. 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.
The bonus from heterosis should be approximately 5% for production and 10% for mortality, fertility, health and survival. Combining ability analysis gca enables plant breeders to select parental lines for crossing and provides the opportunity to understand the nature of gene actions involved in the inheritance of desired traits. Giora benari, uri lavi, in plant biotechnology and agriculture, 2012. Cssa special publication, concepts and breeding of heterosis in crop plants, 25. Heterosis breeding in eggplant solanum melongena l. Improved heterosis prediction by combining information on dna and. When two homozygous inbreeds a true breeding line obtained by continuous inbreeding of genetically unlike constituents are crossed together, the resulting hybrids obtained from. 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. Heterosis refers to the phenomenon that progeny of diverse varieties of a.
It was the first criterion in the initial domestication of plants thousands of years ago. Department of agriculture, agricultural research service, department of genetics, north carolina state university, raleigh, north carolina 27695. Sandeep kumar bangarwa the term heterosis was first used by shull in 1914. 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. Improved heterosis prediction by combining information on. Dear colleagues, 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.
Heterosis in plant breeding request pdf researchgate. Combining ability and heterosis in rice oryza sativa l. International conference on vegetables, november 1114, bangalore, p. When these species are subjected to selfing or inbreeding they show severe reduction in vigour and fertility.
Heterotic groups are created by plant breeders to classify inbred lines, and can be progressively improved by reciprocal recurrent selection. Concepts and breeding of heterosis in crop plants, cssa. Jones 1917 suggested that due to linkage between some dominant and recessive genes, it is not possible to obtain true breeding. High yielding cotton hybrids combining early maturity and resistance to leaf curl virus and. Heterosis is used to increase yields, uniformity, and vigor. In a self pollinated crop like wheat the scope of utilization of heterosis depends mainly on the direction and magnitude of heterosis. 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. Thus, any approach to reliably predict heterosis levels based on properties of the parental lines would be highly beneficial for plant breeding. This results in a major challenge for plant breeders, as usually several thousand combinations of parents have to be tested for identifying the best combinations. Heterosis is prevalent for multiple traits in diverse. Various models have been posited to explain heterosis, including dominance, overdominance, and pseudooverdominance.
Heterosis and hybrid cultivars in onions springerlink. As with a hybrid maize production system, it may also be possible to combine these tall fescue dh. The book contains a wealth of useful information for practicing hybrid rice breeders, seed producers, researchers, and students of plant breeding. Why homozygous heterotic individuals with all dominant genes are not recovered in f 2 ans. Adaptedness is generally a quantitative complex feature of the plant, involving many traits, many of which are quantitative. By further selection based on better specific combining ability and heterotic effect in the. Hybrid breeding food and agriculture organization of the united. The identification of the genetic and epigenetic framework underlying heterosis would be a landmark discovery revolutionizing modern plant breeding by allowing the optimal exploitation of crop productivity and stability. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. 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. The nutritive value of indian fruit literature cited. In this article we will discuss about heterosis or hybrid vigour. Estimation of heterosis and combining ability in maize zea. Plant adaptation is a fundamental process in plant breeding.
Hybrid breeding methods are used in maize, sorghum, rice, sugar beet, onion, spinach, sunflowers, broccoli and to create a more psychoactive. 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. Midparent heterosis is more common in nature, and it is easier to explain by. An elucidation of over a century old enigma in geneticsheterosis. Studies on heterosis and combining ability in bittergourd. Selection of parents for the generation of heterosis. Heterosis or hybrid vigor is the principal reason for the success of the commer. Plant breeding, rajmata vijayaraje scindia krishi vishwa vidhyalaya, gwalior, madhya pradesh, india combining ability and heterosis for grain yield and its attributing traits in bread wheat triticum aestivum l. Heterosis can be classified into midparent heterosis, in which the hybrid shows increased strength which is greater than the average of both parents, and bestparent heterosis, in which the hybrids increased strength is greater than that of the strongest parent. Despite such an extensive use in agriculture, the underlying mechanisms of heterosis are still poorly understood. These observations provide strong support for the model that trueoverdominant genes exist and can drive yield heterosis.
Heterosis is prevalent for multiple traits in diverse maize germplasm sherry a. Department of genetics, university of sbo paulo, piracicaba, brazil. Recognition and exploitation of hybrid vigor or heterosis among individual crosses of plants and animals has a long and distinguished history. Heterosis performance in industrial and yield components. Heterosis was discovered in maize about a century ago and has subsequently been found to occur in. 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. Kafi ghasemi 1 abstract quantitative valuations of observed heterosis for 1 1 traits of 15 f 1 hybrids generated by half diallel crosses of six diverse rice cultivars domsefid, hashemi and binam, three. Springer3 1usdaars, plant genetics research unit, and division of plant sciences, university of missouri, columbia, missouri, united states of america, 2usdaars, u. Journal of plant breeding and crop science full length research paper estimation of heterosis and combining ability in maize zea mays l. If we want to combine both processes, mutation and selection, we encounter. Department of agriculture, agricultural research service, department of genetics, north carolina state university, raleigh, north. Despite its importance in maize production, we know surprisingly little about the genetic basis of heterosis.
Heterosis and hybrid rice breeding sant singh virmani. Pdf heterosis refers to the phenomenon that progeny of diverse varieties of a species or. Cross pollinated species and species reproducing asexually are highly heterozygous. In this paper, we describe a study using mapped genetic markers to explore two important issues in maize genetics, heterosis and genotypebyenviron ment g x e interaction. 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.