The goal of hybrid development is to combine, in a single hybrid, various desirable traits.  For field crops, these traits may include resistance to diseases and insects, resistance to heat and drought, reducing the time to crop maturity, greater yield, and better agronomic quality.  With mechanical harvesting of many crops, uniformity of plant characteristics such as germination, stand establishment, growth rate, maturity, and plant and ear height is important.  Traditional plant breeding is an important tool in developing new and improved commercial crops.