Pedigree Method

• Most popular
• Essentially a plant to row system to develop near pure lines
• Followed by performance testing of resulting strains
• This method and its variants require a lot of record keeping.

Genetic Considerations

1. Additive genetic variability decreases within lines and increases among lines, assuming no selection recall the movement toward homozygosity following the hybridization of unlike and homozygous parents
2. Dominant genetic variability complicates pedigree selection homozygous and heterozygous individuals look alike and therefore you may continually select the heterozygote. Thus, selection can be discontinued with phenotypic uniformity within a line is obtained

Advantages of Pedigree method

1. Eliminates unpromising material at early stages;
2. multi-year records allow good overview of inheritance, and more effective selection through trials in different environments;
3. Multiple families (from different F2 individuals) are maintained yielding different gene combinations with common phenotype
4. Allows for comparison to other breeding strategies

Disadvantages of Pedigree method

1. Most labor, time and resource intensive method; usually compromise between # crosses and population sizes;
2. Very dependent on skill of breeder in recognizing promising material;
3. Not very effective with low h2 traits;
4. Slow; can usually put through only one generation per year, and the right environmental conditions must be at hand for accurate selection.
5. Upper ceiling set by allelic contents of F2; cannot purge selections of undesirable alleles once ‘fixed’.