Superiority of F1 over mid-parent is called:
Relative heterosis, also termed mid-parent heterosis, quantifies superiority of F1 over average performance of its two parents. Mathematically calculated as difference between F1 and mid-parent value MP equals mean of P1 and P2 divided by MP multiplied by 100 to express percentage. Positive estimates indicate dominance and additive by additive interactions aggregating across quantitative trait loci governing yield components, chlorophyll content and stress tolerance. Mid-parent represents expected additive performance under no dominance, so deviation signals non-additive gene action. Although useful to detect combining ability potential, it does not guarantee economic advantage over elite cultivar. Breeders use relative heterosis as preliminary screen before evaluating better-parent and standard heterosis for commercial release decisions in hybrid programs. 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: Falconer Intro Quantitative Genetics heterosis definitions; Singh BD Relative heterosis formula; Acquaah Chapter Heterosis metrics.