The researchers analyzed eight maize hybrids and their parental lines to see how their genetic differences relate to grain yield. They found that the hybrids had an average grain yield of 11.37 tons per hectare, with the highest yield coming from a specific cross. The hybrids showed different levels of yield improvement compared to their parents, with some performing better than others. The genetic distance between the parental lines ranged from 0.55 to 0.61, with an average of 0.58. The researchers discovered a positive correlation between genetic distance and grain yield, as well as with the yield improvement seen in the hybrids.