The researchers studied how different types of maize plants respond to low and high nitrogen levels in the soil. They crossed ten different types of maize plants to create 45 new hybrids, and then tested them in different environments with varying levels of nitrogen. The hybrids were shorter and had taller ears compared to the original plants, making them better for mechanical harvesting. The hybrids also had better husk cover, making them less likely to be damaged by insects or animals. Overall, the hybrids produced more grain than the original plants in both low and high nitrogen conditions, showing that they are more tolerant to low nitrogen levels. The hybrids also flowered and matured earlier than the original plants, indicating that they grow faster.