Breeding widely adapted, popular maize hybrids

Summary World trend is to more maize hectarage grown to fewer, more widely-adapted hbrids. My purpose is to document research events leading to the most popular corn hybrids, Pioneer Brand 3780 and 3732. I provide background on maize adaptedness, on the seed maize business, on commercial maize hybrid development process, and on cultural practice change. I provide historical information on the cultivars: Leaming corn, Reid Yellow Dent, and Minn. 13 were widely-adapted open-pollinated varieties. Shift from open-pollinated to hybrid maize caused a shift in emphasis from local to wider adaptation. The first widely-adapted hybrids were Iowa 939 and U.S. 13. DEKALB 404A was the first popular and most popular double-cross hybrid. Pioneer 349 was the second-most popular double-cross hybrid. The first popular single cross hybrids were DEKALB 805 in medium and DEKALB XL45 in early U.S. Corn Belt in the early-1960's. Cultural practices (higher planting density, narrower rows, more nitrogen, better pesticides, and larger equipment allowing more timely operations) changed greatly in the 1960's and 1970's; allowing fewer, more widely-adapted genotypes to prevail. First hybrid 3780, then 3732 became the most popular hybrid; each exceeded one billion (1 × 10⁹) dollars sales. They were the result of wide-area testing, of utilizing higher plant density stress for selecting inbred lines and for screening hybrids, and of modern information management.