Yield improvement and yield components: A comparison of corn and soybean

Abstract Understanding how crop plants changed to accommodate historical yield improvement contributes to a fuller understanding of the response of the crop to management practices. Data sets of yield and plant population from field experiments for corn ( Zea mays L.) and soybean ( Glycine max (L.) Merr.) were compiled from the literature to evaluate changes in yield and yield components. Most of the data came from management studies and, when there were differences among treatments, the highest‐yielding treatment was used. Yield plant −1 was calculated from yield and plant population. The data sets included both irrigated and non‐irrigated experiments with a total of 231 observations (1906 to 2019) for corn and 172 (1919 to 2018) for soybean. The yield data did not segregate by irrigation treatment, so the data were pooled for analyses. The yield increased linearly for both species (10.4 g m −2 d −1 for corn and 2.6 g m −2 d −1 for soybean). Plant population increased steadily for corn (fivefold) while there was no significant change for soybean. The consistent yield increase coupled with different population trends resulted in completely different trends in yield plant −1 . Yield plant −1 increased in soybean while there was no change in corn. The soybean plant had the flexibility to accommodate the more than twofold increase in yield plant −1 . The corn plant is potentially flexible, but the flexibility did not play a major role in hybrid improvement, so it was necessary to increase the population to accommodate higher yields.