Pure line selection is most suitable for:
Pure line selection most effective in self-pollinated crops because autogamy rapidly drives homozygosity and population consists of mixture of distinct homozygous lines each phenotypically uniform. Selection among lines rather than within captures additive variance of yield traits controlled by many small effect QTL. Crops such as wheat Triticum, rice Oryza, barley Hordeum, groundnut Arachis and chickpea Cicer predominantly selfing with outcrossing below five percent, already purged severe deleterious load, so inbreeding depression minimal and homozygous lines vigorous. Johannsen experiments with beans established pure line theory where selection within homozygous line ineffective. Therefore breeders evaluate individual plant progenies in progeny rows, identify best performing pure line with high harvest index and disease resistance, multiply for varietal release achieving uniformity required for DUS testing and seed certification. This understanding supports competitive exam preparation for NEET, GATE and CSIR NET concepts linking genotype with phenotype through molecular pathways involving transcription factors, hormones and metabolic enzymes that regulate development, adaptation and reproductive biology in applied breeding programs.
Ref: Johannsen 1903 Pure line theory; Allard Principles Plant Breeding pure line selection self pollinated; Singh BD methods.