Rohit karode
- 2. Selection with Progeny Testing It is a method of plant breeding in Cross Pollinated crops. With Progeny Testing:- In this method initially plants are selected on the basis of their phenotype, but the final selection of plant is based on progeny test. This method includes progeny selection on Ear to Row method & Recurrent Selection.
- 3. Progeny Selection (Ear to Row Method) Hopkins in 1908 developed this method, extensively used in maize. A method in which selection is carried out on progenies derived from individual ears is called Ear To Row Method.
- 4. Procedure:- In its simplest form it consists of- 50-100 number of plants are selected on the basis of their phenotype and are allowed to open pollinate . The seeds from indiidual plants are harvested separately. A single row of 10-50 plants i.e. A progeny row, is grown from each selected plant. The progeny rows are evaluated for desirable character and superior are identified.
- 5. Continue... Several phenotypically superior plants are selected fro the superior progenies and selected plants are permitted to open pollinate. Small progeny rows are again grown from the selected plants, and the process of selection is repeated.
- 7. Merits of Ear to Row Method 1. It is based on progeny test and not on the phenotypes of individual plants, hence it is far ore accurate reflection of the genotype than phenotype. 2. Inbreeding may be avoided if care is taken to select a sufficiently large number of plant progenies. 3. Selection schee is relatiely siple and easy.
- 8. Demerits of Ear To Row Method 1. There is no control on pollination and plants are allowed to open pollinate. Thus the selection is based on the maternal parent only. 2. The selection tie is 2 years. Thus the time required for selection is as much as in case of Mass Selection.
- 9. Selfed (S1 or S2) Progeny Testing Method The basic concept behind selfed progeny selection is to increase the magnitude of available additive genetic variation. The additive genetic variation is about 50% higher in S2 progenies than that of S1 progenies.
- 10. Procedure:- The plants in original base population are selfed to produce S1 progenies. The progenies are evaluated next season in replicated multi-environmental trials to identify promising families. The remnant S1 seed of such selected families is then recombined in the third season. Thus one cycle is completed in 3 seasons.
- 11. Continue... Similarly for S2 family selection, selfing of individual plants is continued for 2 years. Thus taking 4 years for one cycle of selection. Here the units of selection and recombination for S2 progenies are S1 progenies.
- 13. Merits of Selfed Progeny Selection:- The magnitude of additive genetic variation is increased by 50% in S2 progenies than that of S1 progenies. The deleterious recessive alleles are exposed & eliminated in the selfed families. The method is more effective for increasing frequency of genes with additive effects. It gives more genetic gain per cycle.
- 14. Demerits of Selfed Progeny Selection:- S1 and S2 family selection need more number of years. S1 and S2 requires more number of selfings to be done which is tedious process in cross pollinated crops.