Pedigree Method and Back-Cross Method | Breeding, Top 4 Methods Used in Cross-Pollinated Crops | Breeding. Or Improvement of asexually propagated crop y selecting superior clones is known as clonal selection. Now it is also used in self pollinated species. Variety A â Recurrent parent (well adapted, high yielding); Variety B â Non-recurrent parent, dominant gene controlled (stem rust resistant). As natural selection acts here, so the progenies selected from long term bulk are far superior than those selected from F2 of short term bulk. Methods of mixed (cross) pollination. Individual plant progenies of F5 generation are planted according to recommended commercial seed rate. 2) This method is commonly used to correct some specific weaknesses of an established variety (Combination breeding). This method is well suited for improvement of characters which can be easily identified and simply inherited. Existence of self-sterility, self-incompatibility, imperfect flowers, and mechanical obstructions make the plant dependent upon foreign pollen for normal seed set. This is so because of their effect on the applicability of certain breeding methods and techniques. The selected line is homogenous; thus, a pure line is more uniform than lines developed by mass selection. Preliminary yield trial with three or more replications is conducted to identify few superior lines. The new variety is not superior in performance than the existing variety except the introduction of single character. Back cross method. 1) Only important characteristics should be recorded. Breeding Methods in Cross Pollinated Crops The most important methods of breeding cross-pollinated species are (1) mass selection; (2) development of hybrid varieties; and (3) development of synthetic varieties. Less attention and labour is needed for this method. 2. Occurrence. 3. Pedigree record may be kept in several ways, but it should be simple and accurate. Individual plant progenies are grown. The multiple characters can be transferred in a stepwise method. Plants or progenies with weaker and visible defects are eliminated at an early stage in the breeding programme. 3. This specially requires the relatedness between the species where the chromosomes can pair during meiosis. But for determining the pedigree of a progeny the breeder has to consult the records of the preveious year. Such as in cotton, the ginning quality of fibre has been improved by back-cross method from the local variety. Pure line is a self pollinated descendent of a self pollinated plant. Pure line selection â¢ 3. The pollen of animal-pollinated plants has a rough surface to help it stick to a pollinator Specific Objectives Theory By the end of the course, the students will be able to i. learn breeding procedures in self and cross pollinated crops ii. ; superior lines are released as new variety. The F1 generation seeds are space planted and seeds from these plants are harvested in bulk. Progenies harvested in bulk since they become homozygous. When the animal visits another flower, some of this pollen comes off onto the stigma pollination has occurred. The undesirable progenies are rejected. Seed multiplication and distribution to the farmers are carried out. Modification of back-cross method will produce transgressive segregants. This method gives maximum importance on the breeder to use his/her skill and judgement about the selection of plants and progenies. Interspecific Transfer of Simply Inherited Characters: Mainly the character like disease resistance can be transferred from related species to cultivated species. 3) It is also used in the selection of new superior recombinant typeâs i.e Transgressive breeding. both stamen and pistil in the same bloom) and readily transfer pollen from the stamen to the pistil with even the gentlest breeze. In both the systems, the progenies are assigned a different serial number, when they become homozygous and are included in preliminary yield trials. But there are greater chances of error, since more number are to be recorded. 1. This number is given to those homozygous lines that are included in preliminary yield trials. Pedigree refers to record of the ancestry of an individual selected plant. For example, pureline selection applies to highly self-pollinating crops. Larger back-cross progenies would be needed than in case of transfer of a single character, and also it may take long time as in each step all the desired characters may not get expressed. 5. Application of Pedigree Method: 1) Selection of desirable plants from the segregating population in self- pollinated crops. Progeny from plant No 8, selected from the F5 progeny, derived from the plant N0.2 selected from the F4 progeny of the plant No.4 selected from F3 progeny of the Plant No.7 selected in F2. 3. The recurrent parent is first improved for one character then it is used as recurrent parent for introduction of another new character. 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. Individual plant progenies of selfed plants are grown separately. Rust resistant plants are selected and back-crossed to recurrent parent, variety A. Comparison between the transfer of dominant and recessive gene during back- cross method: Quantitative characters are governed by polygenes such as grain size, plant height, maturity time, etc. No great subsequent changes were made. After 6-8 back-crosses, the cytoplasm will be of the donor parent with the genotype of recurrent parent. Inheritance of characters is not individually maintained as in pedigree method. Mass selection is a simplest, common and oldest method of crop improvement, in which large number of plants of similar phenotype are selected and their seeds are harvested and mixed together to constitute the new variety. The plants are tested for rust resistance character. 2. Disclaimer Copyright, Share Your Knowledge
i) Pedigree Method ii) Bulk Method iii) Back Cross Method. In F3 generation also, the individual plant progenies are space planted. The above mentioned criteria are evaluated for these lines. During transfer of such kind of single desirable gene, sometimes some undesirable genes may get transferred. By back-crossing with noble cane these undesired characters are removed. Selection of large number of progenies in every generation is also laborious and time consuming. E. g F2, F3 etc. If the parent plants are closely related varieties then the number of selected F3 plants would be smaller whereas in case of distantly related varieties the number of F3 progenies will be of relatively larger numbers. In some cases, the plant will produce both male and female flowers, like squash or pumpkin plants. At the end of bulking period a large number of progenies are being selected. 2. Starting from F2 generation onwards the seeds are planted at commercial seed rate and spacing. Defects of an established variety can be removed using this method, may be only by introducing a single character. Three different advantages may be achieved from this method: (2) Waiting for selection by environmental disaster. Poor progenies may be simply marked discard. The system of alternate back-crossing and selfing goes on till the desired results are obtained. Such populations are characterized by a high degree of heterozygosity witâ¦ 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. 2) This method is commonly used to correct some specific weaknesses of an established variety (Combination breeding). 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