Which one of the following is the main cause of the lower yield of F2 generation than the F1 generation following hybridization between two inbred lines of maize?

When two inbred maize lines are crossed, the F1 generation exhibits heterosis (hybrid vigor), resulting in superior yield and performance. However, when F1 plants are self-pollinated to produce F2, this heterosis is largely lost due to segregation and recombination of alleles, leading to inbreeding depression. The F2 generation shows increased homozygosity and reduced performance compared to the F1 hybrid.