Plant breeding techniques

The most important step in plant breeding techniques are the screening and selection methods and their types are mentioned with easily understandable pictures

1. PLANT BREEDING TECHNIQUES Screening and Selection methods BY BHAVANISHA RITHIGA S 19BT008 IInd Yr B.Tech Biotechnology

2. What is plant breeding? Plant breeding is the purposeful manipulation of qualities in plants to create new varieties with a set of desired characteristics. Plants with higher qualities are selected by and crossed to obtain plants with desired quality. This results in a plant population with improved and desired traits.

3. Screening methods in plant breeding Field screening Greenhouse screening Laboratory screening Bioassay techniques

4. Selection Methods One major technique of plant breeding is selection, the process of selectively propagating plants with desirable characteristics and eliminating or "culling" those with less desirable characteristics. Types: Pure line selection Mass selection Clonal selecion

5. Pure line Selection Pure line selection is a method in which new variety is developed by selection of single best plant progeny among traditional varieties or land races. In pure-line selection, a large number of plants are selected from a self-pollinated crop and are harvested individually; individual plant progenies from them are evaluated, and the best progeny is released as a pure-line variety. pure-line selection is also known as individual plant selection.

6. Merits This is a good method of isolating the best genotype The variety developed by this method is uniform and more attractive than mass selected variety. . Due to extreme uniformity variety is easily identified in seed certification programmes. This is an easy and cheap method of crop Improvement.

7. Demerits Pure-line selection requires more time and space Isolate only superior genotypes from mixed population. In pure-line selection, new variety can not be developed by breeders. The selection method is applicable only in Self -pollinated crops.

8. Mass selection Mass selection refers to a methods of crop improvement in which individual plants are selected on the basis of phenotype from a mixed population, their seeds are bulked and used to grow next generation. The oldest methods of crop improvement  Applicable to both self and cross pollinated species.

9. Merits Mass selected varieties have provide good protection against diseases. This method is applicable to both self and cross pollinated species. Easy and simple method of crop improvement Varieties developed through mass selection are likely to be wide adapted than any other selection.

10. Demerits Progeny test is not carried out in mass selection The varieties developed through mass selection show variation is not as uniform Varieties developed by mass selection are more difficult to identify than pure-lines in seed certification programmes.

11. Clonal selection Clonal selection is the method of selection of desirable clones from the mixed population of vegetatively propagated crops. It is one of the methods for improving the vegetatively propagated crops such as sugarcane, banana, potato, citrus, ginger etc.

12. Merits Clonal selection is an easy and less time consuming method. Easy maintenance because there is no problem of out crossing and loss of seed viability. Clonal selection is the only method of breeding in vegetatively propagated fruit plants.

13. Demerits There is limited chance of getting new and useful type of variability The multiplication rate is low. It is only useful for vegetatively propagated plants.