Yield Performance of Corn under Heat Stress: A Comparison of Hybrid and Open-Pollinated Seeds during a Period of Technological Transformation, 1933-1955

Abstract

Starting in the 1930s, commercial hybrid corn seeds rapidly replaced the once predominant open-pollinated varieties planted by farmers. By the mid-1950s almost all corn grown in the United States was of hybrid varieties. Observers have argued that the drought-tolerant qualities of these hybrids were a major factor driving farmers' decisions regarding hybrid adoption, but there is little statistical evidence to substantiate this assertion. Hybrid seeds exhibited other attractive qualities, such as improved performance during prime weather conditions, resistance to wind damage, and increased suitability toward mechanized harvesting. Using historical evidence from Zvi Griliches's archival records, we reconstruct data on hybrid corn adoption and yields at a more disaggregated geographic level than previously available. We match these data with historical weather records to measure the extent to which hybrid seeds mediated the adverse effects of drought and extreme heat. Our findings suggest that hybrid corns grown in Iowa from 1928 to 1942 did exhibit both drought and heat tolerance relative to open-pollinated varieties. This result is unique to Iowa in the 1930s. The reduced temperature sensitivity does not appear when comparing yields of hybrid and open-pollinated corns grown in other states at other times.

Historic corn yield, production, and economic value trends in Kansas

“…At the start of hybrid and crop management technology from 1930 to 1970, maximum corn yield variability decreased to ±0.9 Mg ha −1 . Perhaps, commercial hybrids and improved agronomic practices initially decreased corn yield variability (Meyers & Rhode, 2020). However, in the recent years 1970–2020s, maximum corn yield variability from one year to another increased significantly to ±2.0 Mg ha −1 , which is the greatest of the three‐time series.…”

An MILP Model for Corn Planting and Harvest Scheduling Considering Storage Capacity and Growing Degree Units

“…The advent of new farming technologies such as commercial hybrid in the 1930s, preceded a widespread and rapid replacement of the once predominant open-pollinated seed varieties planted by farmers [1]. The widespread use of commercial hybrids is seen in many crops, including corn, sorghum, sugarbeet, and sunflower [2].…”

“…Traditionally, farmers and growers schedule their planting dates in a way that they will have a continuous harvest of crops at the end of growing season [3]. Such a planing schedule has multiple benefits: (1) farmers can better schedule their harvest dates without having to harvest all crops at a time, and (2) the price of crops may change depending on the demand and farmers can decide when to harvest to maximize their profit. Farmers usually extend the harvesting period by either planting varieties with different days to maturity or planting a variety multiple times in succession.…”