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. Heterosis or hybrid vigor as in the familiar f1 hybrids of maize occurs in common hexaploid wheat, but it is difficult to produce seed of hybrid cultivars on a commercial scale as is done with maize because wheat flowers are perfect in the botanical sense, meaning they have both male and female parts, and normally selfpollinate. In this study, 144 diverse wheat genotypes were evaluated for grain iron and yield potential, to estimate the potential for the iron biofortification of high. Heterosis or hybrid vigor has been a major factor in the increased pro. In fact, the biological basis of heterosis is considered by some scientists to be inadequately defined. Identification of heterosis and nature of gene action in. Wheat is the most widely grown crop, occupying 17% of cultivated land. The converse or complement to inbreeding depression in which the value d a. Nascent allohexaploid wheat resembles the tetraploid progenitor t. Analysis of variance anova revealed the presence of significant variance due to general combining ability gca among the parents for all the traits, and. Exploitation of heterotic effects is mainly accredited. 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. The archaeological record suggests that wheat was first cultivated in the regions of the fertile crescent around 9600 bce.
Despite the importance of heterosis in maize and the plethora of research done on heterosis, little is known empirically about the underlying genetic and related physiological basis of heterosis. It was first observed by englendow and pal for grain yield in 1934 and subsequently by other workers. We show that hybrid wheat breeding based on the identified heterotic pattern can boost grain yield through the exploitation of heterosis and enhance recurrent selection gain. Significant heterosis over economic parent and mid parent was observed for almost all the traits studied. The two best crosses excelled the high parent and the standard variety by a significant margin. One of the most promising options is to capture the yield benefits from heterosis in a hybrid wheat programme. Combining ability and heterosis for morphophysiological. Apr 07, 2015 the heterosis, heterobeltiosis, general combining ability gca and specific combining ability sca were examined during rabi crop season of 202014 in hexaploid wheat genotypes. International journal of plant breeding 20 global science books estimation of heterosis in wheat triticum aestivum l. Jun 29, 2007 a proposed model of ga and heterosis in wheat plant height.
Iron biofortification of wheat, instead of supplementation and food fortification, provides a pragmatic approach to solve the problem of iron deficiency. An international symposium on heterosis in crops, 1722 august, 1997, mexico city, mexico. Prediction of heterosis in wheat using coefficient of parentage and rflpbased estimates of genetic relationship. Free fulltext pdf articles from hundreds of disciplines, all in one place gibberellins and heterosis of plant height in wheat triticum aestivum l. The significantly positive contrast between inbreeding depression and midparent heterosis for grain yield indicated the presence of positive additive x additive epistatic interactions.
It is observed by many researchers that positive heterosis is important in some plant traits like grain. Heterosis for yield and yield components were studied in f1, f2 and f3 generations in ten crosses of wheat, triticum aestivum l. Hybrid breeding facilitates a maximum exploitation of heterosis. Manipulation of heterosis is an important strategy for increasing the yield potential of wheat rauf et al. Heterosis and combining ability analysis in bread wheat triticum aestivum l. It has been over 100 years since the discovery of the. To better understand the molecular basis for this success, we performed mrna and small rna transcriptome analyses in. F 1 hybrid seed production system is used for many crops and vegetables because of the high yield due to hybrid vigor. Exploitation of heterosis is considered to be one of the outstanding achievements of plant breeding.
Heterosis and heterobeltiosis studies were done at department of plant breeding and genetics, university of agriculture, faisalabad, pakistan following matzinger approach 1956 among seven wheat. In the first part of the model, combination of upregulation of genes enhancing bioactive ga production and down. Ppt heterosis powerpoint presentation free to view. Studies have shown that the exploitation of heterosis has the potential to overcome the yield plateau in wheat. Wheat is a grass widely cultivated for its seed, a cereal grain which is a worldwide staple food. Pdf estimation of heterosis in wheat triticum aestivum.
To systematically exploit heterosis in hybrid breeding. Estimation of heterosis in different crosses of bread wheat. Exploitation of heterosis is considered to be one of the outstanding achievements of wheat breeding. The rejection of crosses, which shows no heterosis. Heterosis and inbreeding depression for each trait was worked out by utilizing the overall mean of each hybrid over replications for each trait. Eighty and 60% f1 hybrids exceeded the high parent and standard variety to the extent of 44. A quantitative genetic framework highlights the role of. Genomics and heterosis in hexaploid wheat polyploid and. Rewiring the wheat reproductive system to harness heterosis. Study of heterosis for grain yield and its components. 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. Hybrid wheat technology can play an effective role in enhancing grain production. Hybrid rice is now a viable commercial product in countries such as china and india that rely on this plant as their major food cereal.
Ppt heterosis powerpoint presentation free to view id. Studies on heterosis would help for generating breeding strategies of hybrid wheat production. Heterosis and combining ability for major yield traits of. Teixeira da silva2 ejaz ashraf1 1 university college of agriculture, university of sargodha, pakistan 2 faculty of agriculture and graduate school of agriculture. Darwin 1876 also reported that inbreeding in plants results in deterioration of vigour and the crossing in hybrid vigour. Plant breeders exploit heterosis as an effective genetic strategy to increase yield and stress resistance in wheat 1. 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. 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 and combining ability analysis were studied in a 7 x 7 diallel set of bread wheat.
Recent estimates of yield improvements associated with heterosis in wheat range from 3. Gibberellins and heterosis of plant height in wheat triticum. The objectives of our research were to i examine the magnitude of heterosis over the mid. This hybrid vigor is determined by nonmutually exclusive mechanisms, including dominance complementation, overdominance and epistasis. They reported that the crosses showing the best mid and better. The significantly positive contrast between inbreeding depression and mid. Heterosis and combing ability in f1 population of hexaploid. Heterosis is a major yield factor in all breeding categories except line breeding schnell, 1982. Commercial utilization of heterosis was suggested by briggle 15. Heterosis or hybrid vigor is a phenomenon in which a hybrid progeny exhibits superior performance compared to their parental inbred lines.
An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. Analysis of variance revealed the presence of significant variance due to gca among the parent for all. The genetics and exploitation of heterosis in crops. Although the presence of heterosis in wheat was earlier reported in 1919 by freeman, its large scale exploitation had not been realized to recent past.
Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. Potentialities of heterosis breeding in wheat springerlink. Integration of metabolomicbased prediction was not as powerful as genomic prediction. Pdf heterosis and combining ability analysis in bread wheat. Heterosis is a phenomenon in which a progeny of distinct individuals exhibitshigherlower values for the traits than the average of any of the original parent used for the development of the. Estimation of heterosis in wheat triticum aestivum l.
Recently, attempts have been made to understand the genetic and molecular basis of heterosis in wheat. The present investigation entitled combining ability and heterosis for morphophysiological characters in bread wheat triticum aestivum l. 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. Furthermore, the best hybrid outperformed the best line variety by 1.
Conclusion there was considerable genetic potential for improving the grain iron content in the germplasm to provide an economical and long. Estimation of heterosis in different crosses of bread. Nov 26, 2019 heterosis manifestation also indicated some transgressive segregates with high specific combining ability effects. Analysis of a large breadwheat genomic data set through a quantitative genetic framework designed to study the genetic basis of heterosis shows that hybrids outperform midparents in. In wheat freeman 14 first time described heterosis when he found taller f 1 than its tall parents. Heterosis was estimated by using line x tester analysis for yield and various important yield components in 12 crosses of bread wheat, involving 2 lines viz. Combining ability and heterosis for grain yield and its attributing traits in bread wheat triticum aestivum l. Heterosis for some physiomorphological plant traits in. The ability to exploit heterosis hybrid vigour in wheat has historically been difficult due to the strong. Heterosis for winter wheat hybrids evaluated in smallscale north american trials is summarized by pickett 1993 as clearly demonstrating simple heterosis in winter wheat. The many species of wheat together make up the genus triticum. In a self pollinated crop like wheat the scope of utilization of heterosis depends mainly on the direction and magnitude of heterosis.
Exploitation of heterosis through the development of hybrid wheat is one of the most attractive options to increase wheat productivity, but the underlying mechanism remains largely unknown. 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. A proposed model of ga and heterosis in wheat plant height. Naomi miyaji, ryo fujimoto, in advances in botanical research, 2018. Pdf heterosis and combining ability analysis in bread. Heterosis results in the phenotypic superiority of a hybrid over its parents with respect to traits such as growth rate, reproductive success and yield. Heterosis is the increase or decrease in vigour of hybrids when compared with that of its parents sharif et al. 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. Genomebased establishment of a highyielding heterotic. For exploitation of heterosis there is necessary for male sterile line. Assessment of heterosis for morphological and yield. Gibberellins and heterosis of plant height in wheat. Heterobeltiosis and standard heterosis were estimated with the check gw 366 and results are presented in table 2 to 4 and graph 1.
Assessment of heterosis based on genetic distance estimated. In this perspective, we consider that it might be useful to the field to abandon these. The study of heterosis helps the breeders in eliminating less 1 generation itself. The restoration of phenotypic performance by crossing inbred lines to produce a hybrid is called heterosis. Prediction of heterosis in wheat using coefficient of.
Various models have been posited to explain heterosis, including dominance, overdominance, and pseudooverdominance. For days to heading, heterosis over better parent ranged from 8. The genetic changes underlying wheat domestication over thousands of years, however, included not just a collection of beneficial single gene mutations, but also. In this study, heterosis in plant height was determined in two wheat hybrids, and it was found that the increased elongation. Despite the difference in ploidy, allohexaploid wheat can be generated using tetraploid t. Heterosis and combining ability analysis were studied in a 7. Pdf on feb 28, 2020, vinay mahajan and others published heterosis for grain yield in wheat find, read and cite all the research you need on researchgate. Botanically, the wheat kernel is a type of fruit called a. However, the molecular basis for the increased internode elongation in hybrids is unknown. Estimation of heterosis over better parent heterobeltiosis. Heterosis in wheat was first reported in 1919 by freeman. Combining ability and heterosis for grain yield and. 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. 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.
Heterosis and inbreeding depression for grain yield and. Strategies for utilizing heterosis in wheat, rice and oil seed brassica in india, pp. The present investigation was carried out to generate information on heterosis, combining ability and gene action for yield and its components in bread wheat triticum aestivum l. Heterotic genes responsible for elevating crop yields are. The heterosis, heterobeltiosis, general combining ability gca and specific combining ability sca were examined during rabi crop season of 202014 in hexaploid wheat genotypes. Heterosis and combining ability analysis in bread wheat.
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