Tandem Selection: One Trait at a Time

Correct Answer: Tandem Selection

Methods of multi-trait selection were given by Hazel and Lush in 1942. In Tandem selection, only ONE trait is selected at a time; improvement of the next trait begins only after satisfactory gain in the first.

Three Methods of Multi-Trait Selection (Increasing Efficiency)

• 1. Tandem selection → Least efficient; ignores genetic correlations between traits
• 2. Independent culling → A minimum culling standard is fixed for every trait. Example: if minimum standard for milk yield = 10 L/day and fat% = 5%, a cow giving 15 L milk with only 4% fat is CULLED regardless of her milk merit.
• 3. Selection index → Most efficient; all traits are weighted simultaneously using genetic parameters into a single numerical expression. Best method of selection.