Single Seed Descent (SSD) emphasizes selection in:
Single Seed Descent maintains genetic diversity by advancing one random seed from each F2 plant forward without selection until homozygosity increases. Active natural or artificial selection during early segregating generations would favor competitive or early flowering types and eliminate potentially superior recombinants whose phenotype is not yet expressed due to heterozygosity and dominance masking. By postponing rigorous phenotypic evaluation to F5-F6, when lines approach 94-97% homozygosity under selfing, additive genetic variance becomes fixed and heritability rises substantially. In F6
Ref: Goulden CH. SSD method – Crop Breeding; Nature Plants Speed breeding, Watson et al. 2018
