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SELECTION
- 1. PRESENTEDE BY , SONAPETER . P MSC . BOTANY VIMALA COLLEGE THRISSUR
- 2. Selection isthe choosing of the best variety It can be natural or artificial Natural selection – selection which occur naturally Artificial selection – done by man made Important method in plant breeding Practiced in both homozygous and heterozygous population Effectiveness of selection depend on genetic variability of the base population & hereditary NATURAL SELECTION It is a natural process It operate without human interference According to the Darwin's principal “ survival of the fittest “ , plant which survive through the adverse condition are preferred and the weekend one are wiped out .thus nature select the fittest organism
- 3. ARTIFICAL SELECTION Hereselection agent is man Man select better variety from mixed population and try to propagate them Four method : A. Mass selection B. Progeny selection C. Pure line selection D. Clonal selection A. MASS SELECTION In mass selection plant are selected from a mixed population on the basis of their phenotype Applicable to both self and cross pollinated species
- 4. Selection donefor easily observable character – plant height ,grain size ,grain colour , disease resistance Plant are selected on the basis – phenotype The population obtained from the selected plants – uniform than the original plants Two type : Negative mass selection – cutting out of all poorly developed ,less productive inferior plant and remaining superior part are propagated Positive mass selection – only plant with desirable trait are propagated several plants are selected seeds are mixed So, the selected population would be the mixture of several similar looking pure lines Variety developed through mass selection would have considerable genetic variation
- 6. MERIT Simplest ,easiest and quickest method of crop improvement No need of scientific knowledge Pollination do not required for producing new variety Applicable for both self and cross pollinated spieces Provide disease resistance crop They are more stable DEMERIT Selection based on phenotype In cross pollinated crop , large no: of plant have to be selected for propagation , small sample will lead to the inbreeding depression Not applicable to self pollinated speices Importance given to character only
- 7. ACHEIVEMENTS Mass selectionwas extensively used by farmers and agriculturalist for the improvement of self pollinated crop before pure line selection came into practice Mass selection is routinely practice to maintain purity of pure line variety In india it is used in the development of improved varieties of cross pollinated crop like maize , pearl millet and mustard B.PROGENY SELECTION commonly used in cross pollinated crop Progeny selection can be defined as new individual organism that result from the process of sexual and asexual reproduction This method extensively used in maize
- 8. MERIT method issimple and convenient Method more effective than mass selection because selection based on progeny not on phenotype Inbreeding may be avoided if sufficient large number of progeny are selected DEMERIT If the progeny of each plant is tested ,it would required large area which is not practically possible C.PURE LINE SELECTION Also known as individual plant selection In pure line selection a large no : of plants are selected from a self pollinated crop and are harvested individually hence it is known as individual plant selection
- 9. Through pureline selection we can obtain single , homozygous , self pollinated plant It has identical genotype It is non heritable Pure line selection procedure : A. Selection of individual plant from a local variety B. Visual evaluation of individual plant C. Yield trails D. Disease resistance and quality test are done E. Best progeny release a new variety F. Seed multiplication G. Distribution MERIT High yield
- 10. Disease andinsect resistance The variety developed by this method is uniform and more attractive than mass selection Easy method Expensive is very low Easier than hybridization DEMERIT It is very lengthy Heavy laboratory process Applicable only to self pollinated crop It cannot develop new genotype Adaptability to new environment condition is poor
- 12. ACHEIVEMENTS Wheat –NP4, NP6 , NP12 Rice - CO19 CO5 APS1 Cotton – KC1 Cabbage – pusa drum head Onion – pusa read punjal Papaya - CO1 , CO5 Guava – arka mridula D.CLONAL SELECTION A clone is a group of plant produced from a single plant through asexual reproduction Selection of desirable clone from the mixed population is known as clonal selection
- 13. Asexual reproductionavoid segregation and recombination Progeny are identical to their parent All clones are genotipicaly and phenotipicaly similar Clones are stable as pure lines Procedure : A. Clones are selected from mixed population B. Selected plants are asexually propagated C. Seed multiplication D. Evaluation of seed for 3- 4 years E. Thus release of a new variety This method take 9 -10 years MERIT It is only method to improve the clonal crop Clonal propagated variety are highly stable
- 14. Hybrid vigoris easily utilized It is also help to eliminate unproductive and undesirable types DEMERIT In this method no genetic variability can be created This method only applicable to vegetatively propagated crops ACHIEVEMENTS Potato – kufrl red Cavendish – bombay green Mango – niranjan Banana – high rate Tapioca – CO1 Rose – edward rose , andhra rose