Principles of Plant Breeding

Selection

• The selection in these crops is restricted to the material introduce from other source from where a large number of clones are introduced and evaluated under local agro climatic conditions.
• The promising selections are tested in large scale trials which, if successful, can be released for commercial cultivation.
First year

• Grow available mixed variable population; few hundreds too few thousand plants are selected.
• Desirable plant type is selected.
• Highly heritable traits are considered for selection.
Second year

• Grow progeny of the selected clone
• Evaluate them for yield and quality trait.
• 50-100 clones are selected
Third year

• Replicated preliminary yield trial
• Few superior clones are selected.
Fourth to sixth year

• Replicated Multi location trial
• Test for yielding ability.
• Quality and Resistance are evaluated.
• A clone superior to check may be released.
Merits

1.It is the only method of selection. It avoids inbreeding depression and preserve gene combination.
2. It can be combined with hybridisation.
3. Maintain purity of clones.

Demerits

1. It utilises natural variability and cannot create variability.
2. Sexual reproduction is required to create variability through hybridisation.