Heterosis is the increase or decrease in vigour of hybrids when compared with that of its parents sharif et al. In this study, heterosis in plant height was determined in two wheat hybrids, and it was found that the increased elongation. Production of hybrid wheat seed relies on male sterility, the blocking of. Analysis of variance revealed the presence of significant variance due to gca among the parent for all. Hybrid performance and heterosis in spring bread wheat, and their relations to ssrbased genetic distances and coefficients of parentage. Heterosis is a major yield factor in all breeding categories except line breeding schnell, 1982. Estimation of heterosis over the better parent heterobeltiosis may be useful in identifying true heterotic cross combinations. Heterosis and heterobeltiosis studies on plant height of f 1 hybrids of hexaploid wheat showed that all the f 1 hybrids recorded negative heterotic effects for plant height and the cross imdad. Heterosis in internode elongation and plant height are commonly observed in hybrid plants, and higher gas contents were found to be correlated with the heterosis in plant height. Genetic contributions to yield gains of five major crop plants. At present, hybrid breeding also being focused on selfpollinated plants, including wheat krystkowiak et al. Heterosis and combining ability analysis for yield and its components in bread wheat triticum aestivum l.
Ismail agronomy department, faculty of agriculture, fayoum university, 63514fayoum, egypt corresponding author abstract introduction wheat triticum aestivum l. Estimation of heterosis in wheat triticum aestivum l. Four associations with the phytohormone gibberellin ga indicate its involvement in the regulation of heterosis for shoot growth in maize, sorghum, wheat, rice, tomato and poplar. Heterosis and combining ability for grain yield and its contributing traits in bread wheat triticum aestivum l. Dec 22, 2015 selfing species wheat are bred as pureline varieties with stagnating yield growths. An experimental study of hybrid vigor or heterosis in rats.
Introduction in plant breeding programs, diallel crosses are mostly used to provide information on genetic effects for a number of parental varieties or estimates of. The genetics and exploitation of heterosis in crops, 1722 aug. In selfpollinated crops, like wheat, the scope for utilization of heterosis depends mainly upon the direction and magnitude of heterosis. Inspite of its overall success, pearl millet hybrid programme has not been free. Plants free fulltext gibberellins and heterosis in crops. Strategies for utilizing heterosis in wheat, rice and oilseed brassica in india abstr. The study of heterosis helps the breeders in eliminating less 1 generation itself. Jun 24, 2014 bread wheat hexaploid triticum aestivum provides an extraordinary 10,000y story of a new species, established by early farmers, selecting for simple agronomical traits to facilitate efficient and plentiful grain harvest. Ppt heterosis powerpoint presentation free to view id. Gibberellins and heterosis of plant height in wheat. State key laboratory of crop stress biology for arid areas, college of.
Potentialities of heterosis breeding in wheat springerlink. The restoration of phenotypic performance by crossing inbred lines to produce a hybrid is called heterosis. Heterosis and combining ability analysis were studied in a 7 x 7 diallel set of bread wheat. Determining the efficacy of a hybridizing agent in wheat triticum. Combining ability and heterosis analysis for yield traits in bread wheat triticum aestivum. This landmark book deals with heterosis and hybrid seed production of major agronomic crops such as wheat, rice, maize, sorghum, cotton, sunflower, and rapeseed. India had to pass through the barrier of free flow of information. Wheat breeders dealing with various aspects of hybrid wheat found that the standard heterosis for grain yield, on a large plot basis, ranged from 6% b orghi et al. Study of heterosis for grain yield and its components. Heterosis definition, the increase in growth, size, fecundity, function, yield, or other characters in hybrids over those of the parents. Eighty and 60% f1 hybrids exceeded the high parent and standard variety to the extent of 44. Heterosis and combing ability in f1 population of hexaploid. Heterosis for yield and associated traits in bread wheat.
Genomebased establishment of a highyielding heterotic. Heterosis expressed as increase or decrease of f1 hybrid value over midparent relative heterosis, better parent heterobeltiosis and over the best commercial check standard heterosis were calculated for each character using the following formulas suggested by hayes et al. Pdf combining ability and heterosis analysis for yield. To systematically exploit heterosis in hybrid breeding, the concept of heterotic groups and patterns was suggested.
Hence, snp analysis may be utilized in allocating wheat parents to heterotic groups. Heterosis for yield and associated traits in bread wheat triticum aestivum l. The genetic changes underlying wheat domestication over thousands of years, however, included not just a collection of beneficial single gene mutations, but also. The nature and magnitude of heterosis was computed as per cent increase or decrease of the mean values of f 1 over mid parent, better parent bp and standard variety sv. Rahul singh rajput and vs kandalkar the present investigation was undertaken to study the combining ability and heterosis for grain yield and its components in f 1 generation of wheat through line x tester analysis. Pdf estimation of heterosis in wheat triticum aestivum.
We have developed a threestep strategy for establishing a heterotic pattern, which was one of the central unsolved challenges for initiating hybrid. Heterosis and combining ability for grain yield and yield. Heterosis and combining ability analysis were studied in a 7. Fourth most important food grain crop pearl millet pennisetum. Department of plant breeding and genetics, rajasthan agricultural university, s. In a study conducted at wheat research institute, aari, faisalabad during 200405 heterosis and heterobeltiosis were estimated for various quantitative traits in 4x4 wheat diallel crosses. Heterosis and combining ability for grain yield and its. First wheat hybrid pratham is being commercialised. The heterosis of the number of spikes per plant in the f 1 and f 2 generations can be a useful approach for the indirect selection of wheat plants with an improved grain weight and grain yield per.
Heterosis and combining ability for major yield traits of a. The two best crosses excelled the high parent and the standard variety by a significant margin. Heterotic qtl for grain yield mapped near low r pericentromeric regions i. Agronomy free fulltext assessment of heterosis based on. 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. Nascent allohexaploid wheat may represent the initial genetic state of common wheat triticum aestivum, which arose as a hybrid between triticum turgidum aabb and aegilops tauschii dd and by chromosome doubling and outcompeted its parents in growth vigor and adaptability. Heterosis, or hybrid vigor, has contributed substantially to genetic improvements in crops and trees and its physiological basis involves multiple processes. Through heterosis and hybrid seed production in agronomic crops, you will discover valuable information on hybrid seed production methods that is not available in any other single volume. Mar 22, 2014 heterosis or hybrid vigor is a natural phenomenon whereby hybrid offspring of genetically diverse individuals display improved physical and functional characteristics relative to their parents. The converse or complement to inbreeding depression in which the value d a. Heterosis for yield and yield components were studied in f1, f2 and f3 generations in ten crosses of wheat, triticum aestivum l. An evaluation of hybrid traits, yield, and major qtl effect on. Analysis of a large bread wheat genomic data set through a quantitative genetic framework designed to study the genetic basis of heterosis shows that hybrids outperform midparents in. Analysis of variance for combining ability for grains yield and yield.
A quantitative genetic framework highlights the role of. To better understand the molecular basis for this success, we performed mrna and small rna transcriptome analyses in. Heterosis effect has been used in breeding of open pollinated plants such as maize or rye. However, viable seed production technology either through cmschemical based system is yet to be. Manipulation of heterosis is considered to be a vital approach to enhance the yield potential of wheat and is as accepted to be a safe strategy to overcome barriers in wheat yield. Heterosis is a complex phenomenon, which depends on the balance of different combinations of gene effects as well as on the distribution of plus and minus alleles in the parents of a mating system. Heterosis for winter wheat hybrids evaluated in smallscale north american trials is summarized by pickett 1993 as clearly demonstrating simple heterosis in winter wheat. Heterosis and inbreeding depression for each trait was worked out by utilizing the overall mean of each hybrid over replications for each trait.
Pdf heterosis study of certain important traits in wheat. Combining ability and heterosis for grain yield and. Analysis of variance anova revealed the presence of significant variance due to general combining ability gca among the parents for all the traits, and. The present investigation entitled combining ability and heterosis for morphophysiological characters in bread wheat triticum aestivum l. However, total wheat consumption has drastically increased due to over population growth by about 2. Heterosis studies for yield and its components in bread wheat. One of the most promising options is to capture the yield benefits from heterosis in a hybrid wheat programme. Manipulation of heterosis is an important strategy for increasing the yield potential of wheat rauf et al. Heterosis has been increasingly applied in crop production for nearly a century, with the aim of developing more vigorous, higher yielding and better performing cultivars. The freethreshing phenotype is closely tied to the major gene complex q, which is located on the.
Oct 16, 2017 analysis of a large bread wheat genomic data set through a quantitative genetic framework designed to study the genetic basis of heterosis shows that hybrids outperform midparents in grain yield. Wheat is the principal food crop in most areas of the world. Pdf on jun, 2016, abdul wahid baloch and others published heterosis. Book of abstracts the genetics and exploitation of heterosis in crops. The genetics and exploitation of heterosis in crops. Heterosis and combining ability analysis for yield and its. Rewiring the wheat reproductive system to harness heterosis for the. Development of hybrid durum wheat rests on the premise that there is heterosis in this crop elfadl et al. Combining ability and heterosis for morphophysiological. In egypt, wheat is the main cereal crop used as a stable food for urban and rural societies and the major source of straw for animal feeding. Bread wheat, diallel cross, combining ability, gene action, heterosis, received 512 2011 accepted 10 9 2012. Various models have been posited to explain heterosis, including dominance, overdominance, and pseudooverdominance. Heterosis studies for yield and its components in bread wheat over. Ppt heterosis powerpoint presentation free to view.
Rewiring the wheat reproductive system to harness heterosis. Recent estimates of yield improvements associated with heterosis in wheat range from 3. Cytogenetic behavior of fertile tetraploid hybrids of nicotiana rustica and nicotiana paniculata. In contrast, selection gain in maize is high, owing to massive investment sustained by hybrid seed sales, coupled with an efficient exploitation of hybrid vigor. The ability to exploit heterosis hybrid vigour in wheat has historically been difficult due to the strong. Heterosis and combining ability for grain yield and quality. Pdf heterosis and combining ability analysis in bread wheat. Pdf manipulation of heterosis is considered to be a vital approach to enhance the yield potential of wheat and.
Pdf hybrid performance and heterosis in spring bread. Heterosis studies in 12 crosses of bread wheat involving nine varieties uqab2000, punjab96, inqilab91, shafaq06, seher06, lasani08, achyuta, oasis and as2002 and an advanced line v. Finally, the capture of heterosis by the development of wheat hybrids may. The rejection of crosses, which shows no heterosis.
However, the molecular basis for the increased internode elongation in hybrids is unknown. Studies have shown that the exploitation of heterosis has the potential to overcome the yield plateau in wheat. The presence of significant heterosis for grain yield was also accompanied by heterosis for yield. The main target of hybrid crop breeding is to identify parents with high genetic. Pdf estimation of heterosis in wheat triticum aestivum l.
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