Top 4 methods used in crosspollinated crops breeding. Therefore, inbreeding must be avoided or kept to minimum in cross pollinated species. The following points highlight the top four methods used in crosspollinated crops. Outcrossing in plant breeding extension online campus.
In this chapter we are concerned with the methods by which new varieties of self pollinated crop plants originate. Top 3 breeding methods used for crosspollinated crops free download as pdf file. A lot more than just gm crops agricultural biotechnology. The third part of this course, which is on methods of sexual reproduction in crop plants will discuss the importance, concepts of self incompatibility, male sterility and steps involved in making crosses. Topics discussed include the common breeding methods used in improving cross pollinated crops and the theoretical basis for cross pollinated crop breeding. The method is generally used for handling segregation generation may be grouped into three categories. Method of plant breeding in self pollinated plants pedigree methods mass selection and pure line selection cannot be applied to segregating population. Pedigree refers to record of the ancestry of an individual selected plant. Crops with a maximum of 5% natural outcrossing are considered as self pollinated while those with more than 50% as cross pollinated. Crosspollination, where pollen from one plant can only fertilize a different plant. Since cross pollinated species are naturally hybrid heterozygous for many traits and lose vigour as they become purebred homozygous, a goal of each of these breeding methods is to preserve or restore heterozygosity.
In this method of breeding, the best individuals with desired characters are selected on the basis of phenotypic performance in a source population. You can plant different varieties of the same species in the same year as long as the times they flower do not. The breeding methods that have proved successful with self pollinated species are. In contrast to a biparentalcross population, association. The f2 generation is sown at normal commercial planting rates in a large plot. The self pollinated crop breeding course covers the common breeding methods used to improve self pollinated crops and the theoretical basis for self pollinated crops. Most of our crops can be classified as cross pollinated or self pollinated cross pollinated means that an insect or wind normally carries pollen from one plant to another in order to fertilize it self pollinated means that the plant will pollinate and fertilize itself both types require that.
Breeding methods in self pollinated crops authorstream. Cross pollinated crops generally show moderate to severe inbreeding depression. Unit 3 breeding cross pollinated crops topics covered include. However, conventional plant breeding can no longer sustain the global demand with the increasing population, decline in agricultural resources such as land and water, and the apparent plateauing of the yield curve of the staple crops. The commonly used breeding methods of self pollinated plants were developed over a century ago in europe.
Full text of methods of plant breeding internet archive. For selection of a new variety from a segregating population after hybridization the methods followed in selfpollinated crop are of three types. Selffertilization, where pollen from a plant will fertilise reproductive cells or ovules of the same plant. The methods of improving crossfertilized species, on the other hand, tend to focus on improving a population of plants.
The majority of the 5060 main grain crops of the world are predominantly selfpollinated. The fourth module relates to breeding procedures for self pollinated crops which involves pedigree, bulk and back cross methodologies. Population improvement was the earliest breeding method applied to crosspollinated crops. Introduction populations of crosspollinated crops arc highly heterozygous as well as heterogeneous. As previously discussed, selfpollinated species have a genetic structure that has implication in the choice of methods for their improvement. Method of plant breeding in self pollinated plants. A large number of food crops are cross pollinated, including squash, onions, broccoli and spinach. Pdf plant breeding methods in brief for students researchgate. Because breeding programs are dynamic, complex genetic entities, marker phenotype relationships must be evaluated frequently. As stated in the introduction, the methods of selection discussed in chapter 16 for improving selfpollinated species tend to focus on improving individual plants. Selfpollination, or more exactly almost full selfpollination, is the principle mating system found in grain crops and in many vegetables. In this chapter we are concerned with the methods by which new varieties of selfpollinated crop plants originate. Corn and alfalfa breeders began using other breeding methods for the development of. Population improvement strategies for crop improvement.
Methods with crosspollinating crops intrapopulation improvement 1. Maize breeding has unique features that are different from the other extensively cultivated grain species which are primarily selfpollinated. Population improvement was the earliest breeding method applied to cross pollinated crops. Their genetic makeup is such that they show variable inbreeding depression. Breeding methods in cross pollinated crops with major emphasis on population. Delivery this class will be held in the campus extension learning management system lms. This complicates breeding strategies because populations produced by intercrossing these transformants will contain multiple insertion sites, variable dosage at each insertion site, and be highly heterogeneous for expression level. Mass selection, as applied to cross pollinated crops is essentially the same as that applied to self pollinated crops. Only a few such as maize, rye, pearl millet, buckwheat, or scarlet runner bean are crosspollinated. Breeding crosspollinated and clonally propagated crops. Diversity is created to develop parents with beneficial genetic combinations conventional breeding. Chapter 17 from principles of plant genetics and breeding. A modified synthetic breeding method is proposed for crosspollinated crops such as white. Pedigree breeding is a method of genetic improvement of selfpollinated species.
Application of biotechnology in plant breeding programs. In cross pollinated crops like corn and alfalfa, mass selection was the first type of genetic improvement undertaken. Only those breeding and selection methods are suitable for a crop which does not interfere with its natural state or ensure the maintenance of such a state. Pdf breeding strategies of self pollinated crop with. Top 3 breeding methods used for crosspollinated crops plant. Unit iv multiline breeding differences between multiline and purelines procedure merits and demerits achievements population breeding approaches diallel selective mating scheme merits and demerits. Basically, the selection procedure of the best progenies was optimized, particularly with the development of agricultural experimentation based on the publications of fisher. Request pdf breeding methods in cros spollinated species plant breeding is the genetic improvement of plants and is considered to be both a science and an art. Most of our crops can be classified as cross pollinated or self pollinated cross pollinated means that an insect or wind normally carries pollen from one plant to another in order to fertilize it self pollinated means that the plant will pollinate and fertilize itself both types require that you crosstone plan with another in.
Techniques from both self and crosspollinated crops are. Genetics and plant breeding course structure at a glance. Topics include the common breeding methods used in improving crosspollinated crops and the theoretical basis for crosspollinated crop breeding. Jul 02, 2015 such lines often have to be included to increase the number of parental lines making up the synthetics as lines with outstanding gca are limited in number synthetics can be produced and maintained only in crosspollinated crop species, while hybrid varieties can be produced both in self and crosspollinated crops 46.
The fourth module relates to breeding procedures for self pollinated crops which involves pedigree, bulk and backcross methodologies. Backcross breeding method 410 hort 407 1 plant breeding methods i. Controlled hybridization and selection, back crossing and selection, mutation breeding. Breeding self pollinated crops hybridization methods hybridization and gene recombination generate new genotypes. Selection of superior plants is based on the genotype commonly used in cross pollinated and often cross. The commonly used breeding methods of selfpollinated plants were developed over a century ago in europe. Review article timelines in conventional crop improvement. The selection cycle may be repeated one or more times to increase the frequency of favourable alleles. Selection methods in plant breeding based on mode of. Plant breeding plant breeding breeding self pollinated species. Recurrent selection is an important breeding method employed to improve the populations of crop plants particularly those of cross pollinated species.
A multistage longterm strategic process new characteristic added germplasm collection is routinely monitored and recycled with new genetic combinations and traits plants suited for specific environments are cross pollinated new genetic. Only a few such as maize, rye, pearl millet, buckwheat, or. Corn and alfalfa breeders began using other breeding methods for the development of new varieties. Recurrent selection is an important breeding method employed to improve the populations of crop plants particularly those of crosspollinated species. Contents introduction characters of cross pollinated crops methods of breeding in cross pollinated crops mass selection progeny selection or eartorow method. Some examples of crosspollinated crops are alfalfa, rye, herbage grasses, forage legumes, red clover, some maizes. Plant breeding plant breeding breeding selfpollinated species. For example, it is impossible to create a hybrid of a cucumber and a zucchini as they are separate species within the same family. Index sn lecture page no lec 01 aims and objectives of plant breeding 15 lec 02 modes of reproduction 610 lec 03 apomixis classification and significance in plant breeding 1116 lec 04 modes of pollination 1721 lec 05 classification of plants 2224 lec 06 botanical description and floral biology 2529 lec 07 maize zea mays 2n 20 3033. Cultivar development in crosspollinated species compared to self pollinated species, cross pollinated species differ in their gene pool structure, and in the extent of genetic recombination unselected populations typically consist of a heterogeneous mixture of heterozygotes. Plant breeding breeding selfpollinated species britannica. When these methods are used it is required that either plants are handpollinated or pollinators must be introduced into the cagedbagged environment.
Individual plant selection, mass selection, inbreeding and hybridization, recurrent selection, synthetics, composites. In understanding whether a plant is true breeding homozygous or segregating heterozygous for a particular character in the assessment of the breeding value of a plant features of progeny selection. Students learn standard breeding methods and theories associated with selfpollinated and inbred crosspollinated crops, specifically, pedigree, bulk, singleseed descent, and. Plant breeding methods and use of classical plant breeding. Students learn about creating populations, recurrent selection methods, with and without progeny tests, and hybrid production practices. Serving as invaluable tools are mutagenic irradiation and isotope tracer techniques, which are incorporated into the various breeding.
Students learn standard breeding methods and theories associated with population improvement of crosspollinated crops in this online class at nebraska. The end result of plant breeding is either an openpollinated op for corn or inbred for rice varieties or an f1 first filial generation hybrid variety. Breeding selfpollinated crops hybridization methods hybridization and gene recombination generate new genotypes. Sc ag seed science and technology department of genetics and plant breeding shiats allahabad up. Since cross pollinated species are naturally hybrid heterozygous for many traits and lose vigour as they become purebred homozygous, a goal of each of.
The bulkpopulation method of breeding differs from the pedigree method primarily in the handling of generations following hybridization. Jul 02, 2015 breeding methods in cross pollinated crops methods of population improvement breeding methods breeding methods with without progeny progeny test test eg. Breeding methods that do not require hybridization. Crosspollination can only occur between members of the same species.
Mass selection progeny test, ear to row method and recurrent selection 5. In contrast to a biparental cross population, association. Breeding crosspollinated crops request pdf researchgate. The selfpollinated crop breeding course covers the common breeding methods used to improve selfpollinated crops and the theoretical basis for selfpollinated crops. Introduction populations of cross pollinated crops arc highly heterozygous as well as heterogeneous. Top 3 methods used in self pollinated crops breeding methods. Breeding methods in crop plants have been developed that exploit the reproductive genetic structure of particular crop populations. Molecular marker technology, marker assisted selection in plant breeding. The methods of improving cross fertilized species, on the other hand, tend to focus on improving a population of plants. Top 3 breeding methods used for crosspollinated crops.
The latest edition of this venerable text provides a broad overview of the science of plant breeding, and provides students and breeders with essential fundamental information along with. Those with rates of crosspollination lying between the two. Introduction to onfarm organic plant breeding organic seed. Individual plant progeny is selected from f2 and subsequent generations, and their progenies are tested.
As stated in the introduction, the methods of selection discussed in chapter 16 for improving self pollinated species tend to focus on improving individual plants. Breeding methods in crosspollinated species request pdf. Association breeding strategies utilize phenotypic and genotypic information to increase gain from selection and reduce selection cycle time. Gridded selection is one technique that can be used when doing mass selection to. Consequently, breeding methods for cross pollinated crops aim at preventing inbreeding. It is due to such reasons that imposition of selffertilization on cross pollinating crops leads to drastic reduction in their performance. Qtl quantitative trait loci, genetic analysis and characterization of crops with various dna markers and isozymes. Hybridization in self pollinated crops may occur naturally, albeit usually at a low frequency, or through controlled cross pollinations. Breeding strategies for developing transgenic white clover. Hybridization in selfpollinated crops may occur naturally, albeit usually at a low frequency, or through controlled crosspollinations. As previously discussed, self pollinated species have a genetic structure that has implication in the choice of methods for their improvement. Breeding methods in cross pollinated crops with major emphasis on. The course can be taken individually or as the 1st of 3 modules in plant breeding module 2.
Crops with a maximum of 5% natural outcrossing are considered as selfpollinated while those with more than 50% as crosspollinated. Topics discussed include the common breeding methods used in improving crosspollinated crops and the theoretical basis for crosspollinated crop breeding. This short note written on the title of plant breeding methods. Crossing between two inbreds or varieties is called single. Maize is a crosspollinated species with unique and separate male tassel and female ear organs.
Breeding methods normally adopted are of three types 1. Highspeed internet access, email, and the ability to view video files. In crosspollinated crops like corn and alfalfa, mass selection was the first type of genetic improvement undertaken. This article throws light upon the top three breeding methods used for crosspollinated crops. Methods with cross pollinating crops intrapopulation improvement 1. The challenge of the plant breeder is to develop better varieties. The types of genotypes that can be generated are a function of the genotypes of the parents. Breeding field crops, 5th edition, thoroughly covers the field of plant breeding. A population is a large group of interbreeding individuals. Crosspollinated crop breeding agronomy and horticulture online.
The breeding methods commonly used in cross pollinated crops. Association breeding strategies for improvement of self. Students learn standard breeding methods and theories associated with self pollinated and inbred cross pollinated crops, specifically, pedigree, bulk, singleseed descent, and. At maturity the crop is harvested in mass, and the seeds are used to establish the next generation in a similar plot. Breeding methods in cross pollinated crops methods of population improvement breeding methods breeding methods with without progeny progeny test test eg.
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