Pedigree Selection vs. Single Seed Descent (SSD): A Comparative Perspective

    Plant breeders often face a crucial decision when advancing segregating generations: whether to use Pedigree Selection (PS) or Single Seed Descent (SSD). Both methods have distinct advantages depending on the nature of the trait being selected for, and several studies have compared their effectiveness.

Pedigree Selection (PS): Best for High Heritability Traits

Computer simulations and experimental data suggest that Pedigree Selection is the most efficient approach when dealing with traits that have high heritability. This method works well because it relies on careful record-keeping and visual selection, allowing breeders to consistently identify superior plants. When multiple traits are considered simultaneously, PS also proves effective.

However, PS requires significant time, effort, and resources since selection must begin in the early segregating generations. Maintaining pedigree records and conducting early yield trials can make the process labor-intensive and expensive.

Single Seed Descent (SSD): Faster and More Cost-Effective

In contrast, Single Seed Descent has been shown to be more efficient when dealing with traits of low heritability and when the goal is to advance generations rapidly. SSD minimizes early selection pressure, thereby reducing costs and avoiding the need for extensive yield testing until later generations. This makes it particularly advantageous for advancing large populations in a relatively short time.

Research also indicates that SSD can sometimes outperform PS because it allows greater recombination to occur before final selection is made. As a result, potentially superior high-yielding lines may emerge from SSD populations.

Key Differences Between PS and SSD

• PS emphasizes careful selection and record maintenance in early generations, making it suitable for traits that are easy to observe and highly heritable.
• SSD minimizes early selection, focuses on rapid generation advancement, and reduces costs, though it may carry the risk of rejecting promising lines too early.

Conclusion

The choice between Pedigree Selection and Single Seed Descent ultimately depends on breeding objectives, trait heritability, and available resources. While PS is preferable for highly heritable traits and detailed genetic tracking, SSD is more practical for rapid generation turnover and cost-effective breeding.

In practice, many breeders adopt a combined strategy—using SSD to quickly advance populations and then applying pedigree selection in later generations to refine and select superior lines.