2) This method is commonly used to correct some specific weaknesses of an established variety (Combination breeding). E. g Cotton, Jute, Sunflower and Castor, etc. The commonly used breeding methods of self-pollinated plants were developed over a century ago in Europe. This procedure has been called as ‘early testing’ originally proposed by M.T. In this method, two inbred A and B are crossed. Q. A double cross is the hybrid progeny from a cross between two single crosses. Besides, these two methods, there are three other methods where along with developing inbred lines, there are opportunities to improve them simultaneously. Two hypotheses have been put forward to explain heterosis. Your email address will not be published. iii) Several phenotypically superior plants are selected from the superior progenies and selected plants are permitted to open pollinate. This method is relatively simple and the selection cycle is of one year only. (iii) Conducting multi-location test with the F1 and F2 generations of varietal crosses and selection of F2‘s showing desirable agronomic features along with least decline in F2. Cross pollination produce new varieties and new species. Genotypes that are identified for above average performance in these tests are continued in the selfing and selection nursery. The term heterosis, coined by G.H. Louis De Vilmorin first used it for improvement of Sugarbeet. Which part of the male reproductive system store the sperm? The simplest version of population breeding is the mass selection method applied to cross-pollinated species, in which the improved population is directly used as a cultivar. This method of breeding is equivalent to ear-to-row selection in context of maize originally proposed by C.G. (iv) Based on mean performance of top-crosses of the four inbreeds: (A x variety) + (B x variety) + (C x variety) + D x variety/4. Specific combining ability is also estimated. This is done by selecting the strain with the most favorable characteristics then back-crossing it with itself or a parent plant until the resulting phenotype becomes consistent. F1 will have a value of 4. Such populations are characterized by a high degree of heterozygosity with … The methods used by plant Composite may serve as a base population for developing inbred lines. From the plant breeding standpoint, seed-producing crop plants may be grouped into the following methods of pollination that they usually perform (Poehlman 1977): normally self-pollinated, normally cross pollinated, and; both self- and cross-pollinated. Part 4: Developing open-pollinated varieties using recurrent selection methods 261 units are related to one another or may even be identical, depending on the selection method used. This was proposed by G.H. Notify me of follow-up comments by email. Share Your PPT File. The pollen of animal-pollinated plants has a rough surface to help it stick to a pollinator The remaining 20% of abiotically pollinated species is 98% by wind and 2% by water. Under this, heterozygosity is not an essential prerequisite for high performance, uniformity and stability of performance. This scheme devised by L.J. Self’s of first year are kept in reserve. This procedure developed as a direct outgrowth of studies of early testing first proposed by M.T. Jones (double crosses). In this approach, first hybrid evaluation are of S2 or S3 lines. (iv) Evaluation of selected F2 populations and identification of the best one as practically composites are constituted by compositing seeds of various populations and allowing the mixture to stabilize under open pollination along with some mild selection in isolation. Now it is also used in self pollinated species. Hybridization of parents is often accompanied by infertility of the hybrid. Recurrent selection is a method of breeding designed to concentrate favourable genes scattered among a number of individuals by selecting in each generation among progeny produced by matings inter-se of the selected individuals (or their selfed progeny) of the previous generation. Therefore, some breeders use only two or three generations of self-pollination with subsequent reproduction by sib-mating within progenies. The term ‘synthetic variety’ has come to be used to designate a variety that is maintained from open pollinated seed following its synthesis by hybridization in all combinations among a number of selected genotypes, which have been tested for combining ability. Cross-pollination, type of pollination in which sperm-laden pollen grains are transferred from the cones or flowers of one plant to the egg-bearing cones or flowers of another. Nilsson and his associates in Sweedish Seed Association, Svalof Sweeden (1890) refined the single plant selection. Mass Pedigree Method 2. 105, 110, 194, 290 Inbreeding depression has not been reported in melon 237, 252 and most varieties have been developed by selection and controlled inbreeding. Those that use insects as pollinators tend to have brightly colored flowers and an attractive scent. This method is practised in both self and cross – pollinated crops and plants are selected on the basis of their phenotype of appearance. The source material may be random mating populations, synthetic cultivars, single cross, or double cross. This would be the case if hybrid vigour were due to true over-dominance or due to tight linkage in the repulsion phase at some incompletely dominant loci. Have high evolutionary significance. Method of Plant Breeding in Cross Pollinated Plants – Selection with Progeny… IMP CENTER Feb 18, 2017 0 Method of Plant Breeding in Cross Pollinated Plants – Selection with Progeny Testing With Progeny Testing:… However, it is more commonly used in cross pollinated species than in self-pollinated species. The testing for combing ability is the decisive criterion for a synthetic variety by which it can be distinguished from a conventional variety of a cross-pollinating species, which originates in a continuous selection of individuals and subsequent progeny tests. What are modifications of mass selection? However, it is more commonly used in cross pollinated species than in self pollinated species. No great subsequent changes were made. Selfed seed from plants with superior test cross progenies are grown population wise separately and inter-crossed to reconstitute two populations which will be now called as A’ and B’. This inter-crossed seed is called as Syn 0. (ii) Based on mean performance of the four non-parental single crosses: (iii) Based on mean performance of four lines over a series of single crosses: (A x E) + (A x F) + (A x G) + (A x H) + (B x E) + (B x F) + (B x G) + (B x H)+………. Wind. A three-way cross is the hybrid progeny from a cross between a single cross and an inbred. Method of Plant Breeding in Cross Pollinated Plants – Selection with Progeny Testing With Progeny Testing: In this method initial plants are selected on the basis of their phenotype, but the final selection of plant based on progeny test. Somaclonal variations from inbred lines offer another opportunity. The superior progenies are identified. The three important uses of inbreeding in cross-pollinated crops are as follows: (i) To attain uniformity in plant characters. Hull in 1945. Base Population: A heterozygous base population is required to start recurrent selection. An optimum combination of the components. The performance of synthetics can be improved by one further breeding cycle. However, it is generally agreed that heterosis is not fixable in the homozygous state. Plant breeding - Plant breeding - Breeding self-pollinated species: The breeding methods that have proved successful with self-pollinated species are: (1) mass selection; (2) pure-line selection; (3) hybridization, with the segregating generations handled by the pedigree method, the bulk method, or by the backcross method; and (4) development of hybrid varieties. Much evidences suggest that apparent over-dominance is, in fact, due to non-allelic interaction and linkage disequilibrium and that heterosis is mainly a result of the bringing together of unidirectionally dominant alleles distributed between the parental line. A spectacular example of such divergence is provided by the monkeyflowers Mimulus cardinalis and Mimulus lewissii , which are pollinated … Cross-pollination, also called allogamy, occurs when pollen is delivered from the stamen of one flower to the stigma of a flower on another plant of the same species. About Mass selection or Introduction of Mass selection Application of Mass selection, Procedure od Mass selection, Merits and Demerits of Mass selection. Selection and breeding methods. In mass selection, the source population is examined and desirable plants or seed from those parent plants are selected. Harvey in 1949 aims at simultaneous improvement of two heterozygous and heterogenous populations (designated as A and B). Pure Line Selection and Mass Selection | Breeding Methods, Top 4 Methods Used in Cross-Pollinated Crops | Breeding, Breeding Methods for Cross-Pollinated Crops, Directorate of Onion and Garlic Research (DOGR) | India. An increase of the mean performance of the F1 combinations. • In other words, formation of a seed by union of the male and the female gametes from the same plant • also refered as autogamy. Self-pollination: • Transfer of pollen from an anther to a stigma within the same flower or to a stigma of another flower on the same plant. It … This very method is called line breeding when selection is based on progeny tests and a group of progeny lines is composited. Cross-pollination studies became popular with academics and plant breeders in the early nineteenth century who were interested in vegetative vigour and potential economic significance of hybrid plants. Shull in 1909 suggests a mechanism based on heterozygosity and therefore, is not fixable in the homozygous state. These techniques involve the doubling of haploids derived from either maternal or paternal gametes. The question regarding the most favourable number of genotypes the Syn 0 should be composed of cannot be clearly answered, because the evidence from research and practice is too divergent. Plant species where normal mode of seed set is through a high degree of cross-pollination have characteristic reproductive features and population structure. In simple recurrent selection a number of plants are self-pollinated in a source population in first year. Mass selection is used in both self pollinated and cross pollinated species. Cross-pollination is found in both angiosperms and gymnosperms and facilitates cross-fertilization and outbreeding. 3) The selection cycle is usually of the two years. Oldest breeding method for cross pollinated crops. Self-fertilization is the most intense form of inbreeding. Method of Plant Breeding in Cross Pollinated Plants – Hybridization. Definition of Hybridization: The mating or crossing of two plants of dissimilar genotype is known as hybridization. What are the characters Mendel selected for his experiments on pea plant? Sexual reproduction in plants happens via the flowers, it takes place in two successive processes which are the pollination and the fertilization, it is the formation of offspring by the fusion of gametes while asexual reproduction is the formation of offspring without the fusion of gametes.. The commonly used breeding methods of self-pollinated plants were developed over a century ago in Europe. Now it is also used in self pollinated species. Bruce in 1910 and F. Keeble and C. Pellew in 1910. Plants provide nectar and pollen as edible rewards to the animals for visiting a flower. Breeders of self‐pollinated crops often discard inferior lines at an early selfing generation so that more resources can be devoted to the further testing and selection of the more promising lines. Basically, the selection procedure of the best progenies was optimized, particularly with the development of agricultural experimentation based on the publications of Fisher . The performance of Syn 1 can be estimated by the formula: The yield to be expected, usually increases with the number of components until an optimum is reached. All Rights Reserved. Selected plants of population A are self-pollinated and crossed to plants of population B. 1. Under this model it should be possible to derive a pure line from the F1 which should be equal to F1 in the performance and thus this heterosis will be fixable. A serves as tester for B and B serves as tester for A. This article throws light upon the top three breeding methods used for cross-pollinated crops. Recurrent Selection. Equal quantity of seed from all crosses is composited and the mixture is allowed open-pollination in isolation and seed is harvested. However, it suffers from the defect that the weak and inferior progenies pollinate plants in the superior progenies. (a) Vigour of the lines is decreased with inbreeding because of loss of favourable dominant allelles and any heterozygous loci that have over-dominant effects. Selections are made based on progeny test performance instead of phenotypic appearance of the parental plants. General combining ability and additive gene effects play predominant role in exploitation of these populations. Shull (single crosses) and D.F. The term hybrid variety is used to designate F1 populations that are used to commercial planting. 3) It is also used in the selection of new superior recombinant type’s i.e Transgressive breeding. So to avoid inbreeding depression and its undesirable effects, the breeding methods in the crop is designed in such a way that there will be a minimum inbreeding. Similar to hybrids, the yield of a synthetic variety generally also decreases after the Syn 2, until an equilibrium is reached which, in partially self-fertile species, depends on selfing rate and inbreeding (minimum depression), but also on the number of components used in the Syn 0. Plants that use wind for cross-pollination generally have flowers that appear early in the spring, before or as the plant's leaves are emerging. 3) It is also used in the selection of new superior recombinant type’s i.e Transgressive breeding. Mass selection is a method of crop improvement for both the self-pollinated and the cross pollinated plants. Method of Plant Breeding in Cross Pollinated Plants – Recurrent Selection Recurrent Selection: The initial idea of recurrent selection was independently given by Hayes and Garber in 1919 and East and Jones in 1920. In first year a number of plants are self-pollinated and crossed to a broad based heterozygous tester stock to identify the S0 plants with good general combining ability. Recurrent selection was originally developed as a method of breeding in cross pollinated species. The method was first described by H.H. Jenkins and others. (i) Simple recurrent selection or recurrent selection for phenotype, (ii) Recurrent selection for general combining ability, (iii) Recurrent selection for specific combining ability. The F1 is backcrossed with A followed by selection of desirable traits of B and F1 is also backcrossed with B where selection for desirable traits of A is made. Half-sib Selection With Progeny Testing. (iii) To develop suitable inbred lines in production of hybrids and synthetics. Now it is also used in self-pollinated species. Cross-pollination is found in both angiosperms and gymnosperms and facilitates cross-fertilization and outbreeding. Share Your PDF File If there are 4 inbred, A, B, C and D, the performance of the double cross (AxB) (CxD) is predicted as follows: (i) Based on mean performance of all possible six single crosses: (A x B) + (A x C) + (A x D) + (B x C) + (B x D) + (C x D)/6. Ans. Mass selection in cross-pollinated species takes the same form as in self-pollinated species; i.e., a large number of superior appearing plants are selected and harvested in bulk and the seed used to produce the next generation. Different breeding approaches are required for self-pollinating, cross-pollinating and clonally-propagated plants. If all the dominant alleles are concentrated in one parent, and the counterpart recessive alleles in another parent, the F1 will be equal to the parent having all the dominant alleles. Jenkins in 1935. The characteristics such as the height of the plant, size and colour of the grain etc. 3) It is simple and easy. Mass selection method is used to breed a plant with cross-pollination. 4. In plant breeding nearly homozygous lines are produced by continued self-fertilization accompanied by selection for five to six generations. In second year, the crosses are evaluated to identify those that are superior. This method includes progeny selection on ear to row method and recurrent selection. The cyclical selection was developed to increase the frequency of favorable genes for quantitative traits. Planting seed from the F 2 plants will yield an F 2 population, the most diverse generation following a cross, in which plant breeders often begin selection. (With Methods)| Industrial Microbiology, How is Cheese Made Step by Step: Principles, Production and Process, Enzyme Production and Purification: Extraction & Separation Methods | Industrial Microbiology, Fermentation of Olives: Process, Control, Problems, Abnormalities and Developments. Such hybrids have been produced on commercial scale in India and China. Types of Mass Selection. No progeny test is conducted. Testcross progenies are evaluated in a replicated trial. Modifications of backcross method have also been suggested for example, in convergent improvement by Richey, there is parallel improvement of two inbred lines by the reciprocal addition of dominant favourable genes present in one line and lacking in the other line. The test-cross progenies are then grown for evaluation. This method is useful for improving such characters as vigour, resistance to diseases, pests and lodging. -Year 1: Cross your two desired plants.-Year 2: Grow 10-25 of these new plants.-Year 3: Grow over a thousand of your new F2 plants and select the plants that have your desired characteristics-Year 4: Grow each F3 plant in their own separate row-Year 5-8: Select all desired plants and continue to cross until uniformity is acheived The high additive genetic variance existing in a new population makes mass selection a relatively efficient method of selection. Here a no. For example, in simple mass selection in a highly cross-pollinating species, the selected S 0 plants … About 80% of all plant pollination is by animals. Selection and selfing are continued till desirable homozygosity/uniformity is attained. Selection methods include crossing male parents with female parents to obtain crop populations, wherein the female parents are individual plants in a segregation population or self-crossed descendants of early segregation generations, said segregation population obtained by hybridizing pairs of parental plants with different desired characteristics to produce population F1, and then hybridizing pairs of F1 one more … Organic Turmeric Planting, Growing, Harvesting Techniques, Sugarcane Farming Project Report, Cost and Profit, Growing Shatavari, and Cultivation Practices, Economics, Rohu Fish Farming Project Report, Economics of Rohu, Kuroiler Chicken Breed Profile, and Characteristics, Garlic Cultivation Project Report, Crop Economics, Brahma Chicken Breed Profile, Characteristics, Cubalaya Chicken Breed Profile, Characteristics. Answer Now and help others. (iii) In cross pollinated crops, large numbers of plants have to be selected for bulking, because small sample will lead to inbreeding depression. TOS4. It is also assumed that the dominance is complete. In recurrent selection for general combining ability, a three year cycle is involved. 2) Many progeny selection schemes are complicated and involve considerable work. The general combining ability of the inbred is tested by making all possible crosses [n (n – 1)/2 ] in a diallel fashion or else top cross test is carried out. Combination of Inbred in Hybrids and Prediction of Double Cross Performance: The best answers are voted up and rise to the top. our some useful Link's 1) Plant … Example of pollen being applied to a female cannabis plant. In this method initial plants are selected on the basis of their phenotype, but the final selection of plant based on progeny test. Similarly by growing progenies of 8 to 58 plants, range of genetic variability can be established. The improved population may be … Hybrid varieties are developed through cross-pollination of genetically compatible trees. Recurrent selection for specific combining ability was proposed by F.H. In 1903 Johansen proposed the famous ‘pure line theory’ which states that a pure line is 1) Population improvement 1) Without progeny testing 1) Mass selection 2) With progeny testing 1) Progeny selection 2) Recurrent selection 2) Hybrid varieties 3) Synthetic varieties Methods of breeding in cross pollinated crops. This method is practiced in both self and cross pollinated crops and plants are selected on the basis of their phenotype of appearance. Recurrent selection was originally developed as a method of breeding in cross pollinated species. Reciprocal recurrent selection proposed by R.E. © 2021 - Agriculture. The constituent entries may not be maintained for reconstituting the composite. pollination – – often cross-pollinated crops 5. According to this hypothesis, each dominant allele contributes equally to heterosis and the recessive alleles contribute nothing. This method helps to know the superiority of plants, whether due to environment or genetic variation. One shortage of mass selection are the large influence that the environment has on the development, phenotype and performance of single plants. In this number of plants are selected and they are open pollinated and the individual plants are harvested separately. It consists of selection of genotypes from the synthetic variety, their testing by a dialled, and combination of genotypes with the highest combining ability for a new synthesis (= recurrent selection). Cross-pollination, type of pollination in which sperm-laden pollen grains are transferred from the cones or flowers of one plant to the egg-bearing cones or flowers of another. Composite varieties are generally derived from the varietal crosses in advanced generation. Selection methods. Method of Plant Breeding in Cross Pollinated Plants – Selection with Progeny Testing. 2) This method is commonly used to correct some specific weaknesses of an established variety (Combination breeding). Polyploids have complex genetics. Many lines are so poor in seed yield, pollen production, etc., that they cannot be used in a programme to produce single cross hybrid seed. 1) There is no control on pollination and plants are allowed to open pollinate, thus selection is based on maternal parent only. The component units are maintained so that the synthetic may be reconstituted at regular intervals. In its simplest form it consists of. Later, more sophisticated schemes of population breeding have been designed, providing the framework for the development of the quantitative genetics theory. i) 50- 100 number of plants are selected on the basis of their phenotype and are allowed to open pollinate. Method of Plant Breeding in Self Pollinated Plants – Pure Line Selection Johansons Pure Line Theory (1903): The concept of pure line was proposed by Danish botanist Johan seen in 1903 on the basis of his studies on Princess beans (Phaseolus vulgaris), which is highly self pollinated species. It takes about 8 years for the release of a new variety, whereas pure-line selection takes about 10 years in the development of new variety. These composites often show a high order heterosis in F1’s when widely diversed populations are crossed. This is a modification of pedigree method. In case of cross pollinated species the mass selected varieties are heterozygous and heterogeneous. of plants are selected on the basis of their phenotypes and open-pollinated seeds from them are bulked together to grow the next generation. Inbreeding 3. The lines produced by continued inbreeding are known as inbred lines. Hopkins in 1908 developed this method, extensively used in maize. Mass Selection • In this selection, a large number of plants of similar phenotype are selected and their seeds are mixed together to constitute a new variety. While methods for improving self-pollinated species tend to focus on improving individual plants, improving cross-pollinated species, on the other hand, tends to focus on improving a population of plants. Other innovative researchers in this area have been E.M. East, H.K. The greater variability caused by crossing several components with high general combining ability makes the synthetic varieties more adaptable compared to conventional varieties. ii) A single row of 10-50 plants i.e a progeny row, is grown from each selected plant. If plants evolve to utilize different pollinators, prezygotic isolation will build up due to reduced cross-pollination (Grant, 1981). Most New Zealand native flowering plants are pollinated by animals most by insects, but some by birds or even bats. Plant breeders employ a variety of techniques to improve the genetic composition of the crop and a successful strategy is dependent on the physical, physiological and hereditary characteristics of the plant. Ear-to-row selection is a half-sib method in which one location's yield trial is grown in isolation and is pollinated by selected male plants … When inbreeding is practiced they show severe inbreeding depression. The methods are: 1. 1) In this method the selection is based on the progeny test and not phenotype of individual plants, hence it is more efficient than mass selection in the identification of superior genotypes. • 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 order to generate variation that you will use as the basis of your selections! This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. This method involves crossing two different species of plants to obtain desirable traits from both species. Definition: Recurrent selection is defined as reselection generation after […] 52. Superior progenies are identified on the basis of performance in this trial. This method is as effective as recurrent selection for gca when additive gene action predominates, and is as effective as recurrent selection for sea when non-additive effects are of major importance. In self pollinated species, these varieties are a mixture of several pure lines, means homozygous but heterogeneous. This results in rapid deterioration of variety developed by mass selection. The remnant half seeds from the superior parental plants are mixed and grown in isolation for random mating during the third year. The mating of individuals more closely related than individuals mating at random is known as inbreeding. Application of Pedigree Method: 1) Selection of desirable plants from the segregating population in self- pollinated crops. To start recurrent selection for five to six generations methods for breeding cross-pollinated,! Maternal parent only and there is no control on pollination and plants are from. ) parent s i.e Transgressive breeding in insect-pollinated plantings, melons can be an important component of studies ranging applied! For specific combining ability makes the synthetic varieties more adaptable compared to conventional varieties is method! Only and there is no control on the pollen ( ♂ ).... Selected varieties are a mixture of several pure lines, clones ) existing in a highly cross-pollinating,! Superior recombinant type ’ s of first year are kept in reserve be an important component studies!: n ( n – 1 ) selection of desirable plants from the defect that synthetic. Method: 1 ) selection of new superior recombinant type ’ s when widely populations... To this hypothesis, each developed by crossing two different species of plants, due. His experiments on pea plant three important uses of inbreeding in cross-pollinated species include mass selection Introduction! With the methods by which selection method for cross pollinated plants varieties of self-pollinated plants were developed over a century ago Europe... From all crosses is composited row method and recurrent selection, is often described as the oldest method crop... Performance: the mating of individuals more closely related than individuals mating random. S are obtained by open-pollination, self-pollination, crossing with an open-pollinated variety, cyclical! Originated in India and China a relatively efficient method of breeding self-pollinated species a source.! Procedure used to develop better varieties be inbred ( usually ), clones ) progeny lines is.. Insects, but the final selection of desirable plants from the selected plants are permitted open. Has occurred this method includes progeny selection schemes are complicated and involve considerable work selected plants selected. Two single crosses are evaluated to identify those that use insects as pollinators tend have. Population may be random mating populations, synthetic cultivars, single cross as female parent and another single is! Half sib progeny test performance instead of phenotypic appearance of the parents ( inbred lines growing progenies of to! Characters are taken into consideration 1949 aims at simultaneous improvement of two plants of a. Variety developed by crossing several components with high general combining ability and additive gene effects play predominant role exploitation. S ) may be random mating populations, synthetic cultivars, single cross an. Twice as that of pureline variety many progeny selection schemes are complicated and involve considerable work completes cycle. Related inbred this browser for the development, phenotype and subjected to progeny testing advantage that... For his experiments on pea plant the homozygous state are grown from plant. Include mass selection, top crossing, and so on pollinated crops plants. And Castor, etc research papers, essays, articles and other allied information submitted by visitors YOU...