Researchers studied different breeding methods in maize to improve grain yield. They found that single cross hybrids had better grain yields than three way cross hybrids and parents. The inbreds' combining ability was important in single cross hybrids. Triallel and quadriallel analyses showed the order of parents clearly. Non-allelic interactions involving dominance were key for improving grain yield through heterosis breeding. The single cross hybrid 88/261 had the highest yield. More economic hybrids for grain yield were seen in three way crosses.