Equations for calculating hybrid breakdown of the recombinant inbred lines and the heterosis of the BCF1 and testcross F1 populations

PopulationaNEquation for measurementb
RILs254HB = RIL − MP, where MP = (Lemont + Teqing)/2
LTBCF1172HMP = F1 − MP, where MP = (RIL + Lemont)/2
TQBCF1177HMP = F1 − MP, where MP = (RIL + Teqing)/2
Z413BCF1192HMP = F1 − MP, where MP = (RIL + Z413)/2
IR64BCF1187HMP = F1 − MP, where MP = (RIL + IR64)/2
  • RIL, recombinant inbred line; HMP, heterosis.

  • a LTBCF1 and TQBCF1s are two BCF1 populations obtained by crossing the RILs with the parents, Lemont (LT) and Teqing (TQ); while Z413F1s and IR64F1s are two testcross F1 populations obtained by crossing the RILs with the testers, Zhong 413 (Z413) and IR64.

  • b HB and HMP are estimates of hybrid breakdown and midparental heterosis. F1's are mean trait values of individual BC or testcross hybrids while RIL is the corresponding female RIL parent for each of the BC or testcross hybrids.