Heterosis and Inbreeding Depression for Grain Yield Variables in Indigenous Maize Germplasm

Heterosis is one of the greatest practical contributions of genetics to the agricultural world and has its most significant expression in maize than other cereal crops. Exploitation of this phenomenon of superior performance of F1 progeny over their parents not only transfigured maize breeding schemes but also constituted the foundation of maize seed industry. Evaluation of per se performance of parental lines and estimation of heterosis and inbreeding depression are prerequisites to start hybrid development program. In this context, we explored heterosis and inbreeding depression in indigenous maize germplasm comprising inbred lines NCMLQ1, NCMLQ2, NCMLD1, NCMLD2, NCMLD3, and NCMLD4. These genotypes were crossed to get ten F1 hybrid combinations, which were used to develop three generations F2, BC1 and BC2. Heterosis (in F1) and inbreeding depression (in F2, BC1 and BC2) were quantified for traits including shelling percentage, kernels per row, kernel rows per ear, and 100-grain weight and grain yield. Non-additive gene action was evident for shelling percentage, kernels per row and 100-grain weight and grain yield for which both heterosis and inbreeding depression were expressed by crosses like NCMLQ2 × NCMLD2 and NCMLQ2 × NCMLD4. The parental lines used in above F1 hybrids could prove useful in exploitation of heterosis and development of hybrids.