5. 1. Ans. 26. Earlier plants used to be introduced through travellers, traders, invaders and merchants. Development of a new variety through identification and isolation of a single best plant progeny from mixed population of self pollinated species is called pureline selection. The crossed seeds of S0 plants with tester is used to evaluate the combining ability of various S0 plants. This selection method is a variation of progeny selection, the main difference is that the selected progenies are allowed for all possible intercrosses through open pollination to provide all kind of recombination. The first step involves the collection of plants or seeds for all possible alleles for all genes in a given crop, which is known as germplasm. What are breeding methods which do not involve hybridization? A foreign variety which is directly recommended for cultivation is called exotic variety. (ii) Pureline varieties have narrow genetic base. The best progeny seeds are multiplied and released as a new variety through seed certification. 17. Pureline selection consists of following steps: (i) Selection of a heterogeneous material as base population. The process involves selection or retention of a large number of individual plants on the basis of superior phenotype, compositing the harvested seeds without progeny-testing, the mixture of seeds is sown in mass to raise the next generation. Q. (ii) It helps in conserving plant biodiversity. What are demerits of Plant introduction? (b) Forest Research Institute (FRI), Dehradun. Through regular mass selection the purity of the pure line varieties is maintained. Once a pure line is developed, the variability is frozen and further selection becomes less effective. It has been predicted for over two decades that molecular marker technology would reshape breeding programs and facilitate rapid gains from selection [1, 2]. Welcome to BiologyDiscussion! (iii) Pureline varieties have narrow adaptation. 1. By selecting parents that are genetically similar, a breeder restricts the amount of variation that will be evaluated in the offspring. 60. (iii) As a parent in developing new hybrids. What are sources of plant collections? Marker-Assisted Selection in Plant Breeding: From Publications to Practice Yunbi Xu* and Jonathan H. Crouch ABSTRACT The volume of publications on the development and to a lesser extent the application of molecu-lar markers in plant breeding has increased dra … Everything you need to know about the introduction and selection methods of plant breeding ! The other 6 give thorough treatments of different aspects of selection indices, such as the evaluation of parental material, the use of computer programming, the development and use of selection indices and their applications in plant breeding plant breeding Subject Category: Techniques, Methodologies and Equipment see more details. Merits and Demerits of Recurrent Selection: Merits: 1. Share Your PPT File. Terms genotype and phenotype were coined by Johannsen in 1909. Ans. Various procedures (selections, hybridization, mutation, etc.) Selection made by human is called artificial selection. 40. The promising strains are observed and harvested for coordinated yield trial for further evaluation. Q. 3. Progenies from individual selected plants are grown separately with proper spacing. Our mission is to provide an online platform to help students to share notes in Biology. Due to extreme uniformity, the variety is easily identified in seed certification programme. (d) Variability can be induced through mutation. Plant breeding is the purposeful manipulation of plant species in order to create desired genotypes and phenotypes for specific purposes. The main demerit of plant introduction is that sometimes new (a) diseases, (b) insects, and (c) weeds get entry in the country alongwith introduced material. Pure Line Selection 3. The term pureline was first used by Johannsen in 1903. Plant material is collected by following methods (ways): Q. Jared Crain, Suchismita Mondal, Jessica Rutkoski, Ravi P. Singh, Jesse Poland, Combining High‐Throughput Phenotyping and Genomic Information to Increase Prediction and Selection Accuracy in Wheat Breeding, The Plant Genome, 10.3835/plantgenome2017.05.0043, 11, 1, (2018). 6. Plant breeding is defined as identifying and selecting desirable traits in plants and combining these into one individual plant. If the selected plant is really superior, its progeny will also exhibit superior performance and vice versa. Comparison of a pureline and a clone is presented below in Table 13.1. (c) Improvement of Old Pure Line Varieties: Pure lines become variable with time, i.e., off type plants appear in pure line. Genomic selection (GS) facilitates the rapid selection of superior genotypes and accelerates the breeding cycle. 38. The superior and similar observations are selected assuming those are homozygous. A large number of improved varieties were developed by this method in many self-pollinated crops: Rice — M-351, Vidisa 60-1, Patni 6, Aispuri, BP 53. It is also known as Vilmorin principle. From a breeding perspective, this provides the basis for selection so that individuals containing the best features of both parents can be identified and further bred. 32. 51. Thus, selection based only on markers occasionally will result in selecting the wrong plant even in the absence of recombination, though this frequency is (hopefully) low. While MAS has been effective for the manipulation of large effect alleles with known association to a marker [5], it has been at an impasse when many alleles of sma… The population ob­tained from the selected plants would be more uniform than the original population. Ans. Q. Ans. direct introduction and indirect introduction. Some desirable traits are incorporated to produce a new variety. Main purposes of plant introduction are given below: (i) To use as new source of food, vegetable, fibre fruit, timber plant etc. What are different types of artificial-selection? Ans. 1. This cycle may be repeated. Q. ‘Major genes’ that are responsible for economically important characteristics are frequent in the plant kingdom. 3. Assignment on Clonal selection and it’s utilization in fruit breeding 2. Ans. Pure line selection is the most extensively used breeding method in early days of crop improvement in India because at that time many genetically variable ‘desi’ varieties were available. The following points highlight the four main of plant breeding methods. What are modifications of mass selection? (b) Recurrent Selection for General Combining Ability: This method is based on the combining ability of the lines or plants. Q. 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