Incorporating genetic diversity for crop improvement. A population is a large group of interbreeding individuals. Population improvement strategies for crop improvement. As stated in the introduction, the methods of selection discussed in chapter 16 for improving selfpollinated species tend to focus on improving individual plants. Breeding methods in crop plants have been developed that exploit the reproductive genetic structure of particular crop populations. However, mass selection was not always effective in producing better varieties. Introduction populations of crosspollinated crops arc highly heterozygous as well as heterogeneous. The methods of improving cross fertilized species, on the other hand, tend to focus on improving a population of plants. Crops with a maximum of 5% natural outcrossing are considered as selfpollinated while those with more than 50% as crosspollinated. This short note written on the title of plant breeding methods. Breeding selfpollinated crops hybridization methods hybridization and gene recombination generate new genotypes. Top 3 breeding methods used for crosspollinated crops. Students learn standard breeding methods and theories associated with selfpollinated and inbred crosspollinated crops, specifically, pedigree, bulk, singleseed descent, and.
Maize is a crosspollinated species with unique and separate male tassel and female ear organs. Specific objectives theory by the end of the course, the students will be able to i. Pedigree breeding is a method of genetic improvement of selfpollinated species. Plant breeding plant breeding breeding selfpollinated species. Breeding field crops, 5th edition, thoroughly covers the field of plant breeding. The methods of improving crossfertilized species, on the other hand, tend to focus on improving a population of plants.
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. Mass selection mass selection is the oldest breeding scheme available for cross pollinated crops. The breeding methods that have proved successful with selfpollinated species are. In this chapter we are concerned with the methods by which new varieties of selfpollinated crop plants originate. The breeding methods commonly used in cross pollinated crops.
Hybridization in selfpollinated crops may occur naturally, albeit usually at a low frequency, or through controlled crosspollinations. Plant breeders use different methods depending on the mode of reproduction of crops, which include. Their genetic makeup is such that they show variable inbreeding depression. 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. Breeding crosspollinated and clonally propagated crops. In contrast to a biparentalcross population, association. Outcrossing in plant breeding extension online campus. Methods with cross pollinating crops intrapopulation improvement 1. Controlled hybridization and selection, back crossing and selection, mutation breeding. Students learn standard breeding methods and theories associated with self pollinated and inbred cross pollinated crops, specifically, pedigree, bulk, singleseed descent, and. Top 3 breeding methods used for crosspollinated crops plant. The course can be taken individually or as the 1st of 3 modules in plant breeding module 2. Diversity is created to develop parents with beneficial genetic combinations conventional breeding.
Qtl quantitative trait loci, genetic analysis and characterization of crops with various dna markers and isozymes. Request pdf breeding crosspollinated crops while methods for improving selfpollinated species tend to focus on improving individual. 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. Since cross pollinated species are naturally hybrid heterozygous for many traits and lose vigour as they become purebred homozygous, a goal of each of.
At maturity the crop is harvested in mass, and the seeds are used to establish the next generation in a similar plot. Breeding method for cross pollinated crop authorstream. 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. Students learn about creating populations, recurrent selection methods, with and without progeny tests, and hybrid production practices. Crosspollination, where pollen from one plant can only fertilize a different plant. Topics discussed include the common breeding methods used in improving crosspollinated crops and the theoretical basis for crosspollinated crop breeding. The majority of the 5060 main grain crops of the world are predominantly selfpollinated. 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. Pedigree refers to record of the ancestry of an individual selected plant. Consequently, breeding methods for crosspollinated crops aim at preventing inbreeding. Breeding methods in cross pollinated crops with major emphasis on population. Hybridization in self pollinated crops may occur naturally, albeit usually at a low frequency, or through controlled cross pollinations.
Only a few such as maize, rye, pearl millet, buckwheat, or scarlet runner bean are crosspollinated. 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. Association breeding strategies for improvement of self. Selection of superior plants is based on the genotype commonly used in cross pollinated and often cross. Chapter 17 from principles of plant genetics and breeding. Full text of methods of plant breeding internet archive. In this chapter we are concerned with the methods by which new varieties of self pollinated crop plants originate. Cultivar development in crosspollinated species compared to selfpollinated species, crosspollinated species differ in their gene pool structure, and in the extent of genetic recombination unselected populations typically consist of a heterogeneous mixture of heterozygotes.
It is due to such reasons that imposition of selffertilization on cross pollinating crops leads to drastic reduction in their performance. Recurrent selection is an important breeding method employed to improve the populations of crop plants particularly those of crosspollinated species. When these methods are used it is required that either plants are handpollinated or pollinators must be introduced into the cagedbagged environment. Selffertilization, where pollen from a plant will fertilise reproductive cells or ovules of the same plant. Application of biotechnology in plant breeding programs. Breeding methods in cross pollinated crops methods of population improvement breeding methods breeding methods with without progeny progeny test test eg. Since crosspollinated species are naturally hybrid heterozygous for many traits and lose vigour as they become purebred homozygous, a goal of each of. Selection methods in plant breeding based on mode of. Selfpollination, or more exactly almost full selfpollination, is the principle mating system found in grain crops and in many vegetables. 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. A lot more than just gm crops agricultural biotechnology.
Population improvement was the earliest breeding method applied to cross pollinated crops. Breeding self pollinated crops hybridization methods hybridization and gene recombination generate new genotypes. Recurrent selection is an important breeding method employed to improve the populations of crop plants particularly those of cross pollinated species. The challenge of the plant breeder is to develop better varieties.
The breeding methods that have proved successful with self pollinated species are. 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. Plant breeding breeding selfpollinated species britannica. Backcross breeding method 410 hort 407 1 plant breeding methods i. Highspeed internet access, email, and the ability to view video files. Because breeding programs are dynamic, complex genetic entities, marker phenotype relationships must be evaluated frequently. 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. Review article timelines in conventional crop improvement. 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.
Serving as invaluable tools are mutagenic irradiation and isotope tracer techniques, which are incorporated into the various breeding. For selection of a new variety from a segregating population after hybridization the methods followed in selfpollinated crop are of three types. Those with rates of crosspollination lying between the two. Only a few such as maize, rye, pearl millet, buckwheat, or. Delivery online learners have the option of participating in live lectures presented twice weekly to facetoface students or viewing the taped lectures online in extension. Crossing between two inbreds or varieties is called single.
The following points highlight the top four methods used in crosspollinated crops. Cross pollinated crops generally show moderate to severe inbreeding depression. Methods with crosspollinating crops intrapopulation improvement 1. In contrast to a biparental cross population, association. The types of genotypes that can be generated are a function of the genotypes of the parents. Breeding methods normally adopted are of three types 1. Techniques from both self and crosspollinated crops are. Molecular marker technology, marker assisted selection in plant breeding. As previously discussed, selfpollinated species have a genetic structure that has implication in the choice of methods for their improvement. Some examples of crosspollinated crops are alfalfa, rye, herbage grasses, forage legumes, red clover, some maizes. Breeding methods in cross pollinated crops with major emphasis on. The method is generally used for handling segregation generation may be grouped into three categories.
Population improvement was the earliest breeding method applied to crosspollinated crops. The fourth module relates to breeding procedures for self pollinated crops which involves pedigree, bulk and back cross methodologies. Breeding methods in self pollinated crops authorstream. Breeding methods in crosspollinated species request pdf. Introduction populations of cross pollinated crops arc highly heterozygous as well as heterogeneous. 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. Top 4 methods used in crosspollinated crops breeding. 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.
Unit 3 breeding cross pollinated crops topics covered include. Top 3 breeding methods used for crosspollinated crops free download as pdf file. Crosspollinated crop breeding agronomy and horticulture online. In this method of breeding, the best individuals with desired characters are selected on the basis of phenotypic performance in a source population. Contents introduction characters of cross pollinated crops methods of breeding in cross pollinated crops mass selection progeny selection or eartorow method. Sc ag seed science and technology department of genetics and plant breeding shiats allahabad up. Pdf breeding strategies of self pollinated crop with. Plant breeding methods and use of classical plant breeding. Introduction to onfarm organic plant breeding organic seed. Topics include the common breeding methods used in improving crosspollinated crops and the theoretical basis for crosspollinated crop breeding. Jul 02, 2015 breeding methods in cross pollinated crops methods of population improvement breeding methods breeding methods with without progeny progeny test test eg. 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.
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. Mass selection, as applied to cross pollinated crops is essentially the same as that applied to self pollinated crops. This article throws light upon the top three breeding methods used for crosspollinated crops. Consequently, breeding methods for cross pollinated crops aim at preventing inbreeding. Crosspollination can only occur between members of the same species. A modified synthetic breeding method is proposed for crosspollinated crops such as white. Plant breeding plant breeding breeding self pollinated species. 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. Association breeding strategies utilize phenotypic and genotypic information to increase gain from selection and reduce selection cycle time. The commonly used breeding methods of selfpollinated plants were developed over a century ago in europe. Breeding strategies for developing transgenic white clover. Method of plant breeding in self pollinated plants.
As previously discussed, self pollinated species have a genetic structure that has implication in the choice of methods for their improvement. 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. The selfpollinated crop breeding course covers the common breeding methods used to improve selfpollinated crops and the theoretical basis for selfpollinated crops. Individual plant progeny is selected from f2 and subsequent generations, and their progenies are tested. Genetics and plant breeding course structure at a glance. In cross pollinated crops like corn and alfalfa, mass selection was the first type of genetic improvement undertaken. Mass selection progeny test, ear to row method and recurrent selection 5. Students learn standard breeding methods and theories associated with population improvement of crosspollinated crops in this online class at nebraska. Breeding crosspollinated crops request pdf researchgate. Crops with a maximum of 5% natural outcrossing are considered as self pollinated while those with more than 50% as cross pollinated. Gridded selection is one technique that can be used when doing mass selection to.
The bulkpopulation method of breeding differs from the pedigree method primarily in the handling of generations following hybridization. Breeding methods that do not require hybridization. The selection cycle may be repeated one or more times to increase the frequency of favourable alleles. Basically, the selection procedure of the best progenies was optimized, particularly with the development of agricultural experimentation based on the publications of fisher. Maize breeding has unique features that are different from the other extensively cultivated grain species which are primarily selfpollinated. 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. Corn and alfalfa breeders began using other breeding methods for the development of. The fourth module relates to breeding procedures for self pollinated crops which involves pedigree, bulk and backcross methodologies.
Top 3 methods used in self pollinated crops breeding methods. The f2 generation is sown at normal commercial planting rates in a large plot. Method of plant breeding in self pollinated plants pedigree methods mass selection and pure line selection cannot be applied to segregating population. A large number of food crops are cross pollinated, including squash, onions, broccoli and spinach. Therefore, inbreeding must be avoided or kept to minimum in cross pollinated species. Individual plant selection, mass selection, inbreeding and hybridization, recurrent selection, synthetics, composites.
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