Plant Breeding History

Plant Breeders help farmers succeed in growing crops in a changing world. One of the most important choices a farmer makes every year is what specific genetic type or cultivar they will grow in a particular field on their farm. However, a cultivar that produced a successful crop one year may fail to be successful the next year because of new environment stresses. The plant breeder only succeeds in helping farmers if they can identify new varieties that have the genetic characteristics to grow well in future and changing environments.

Figure 1. U.S. wheat yields. Each yield per acre dot represents a single year from 1866–2018. All types of wheat, including Spring and Winter wheat is included in Yield per acre. Data obtained from USDA Crop Production Historical Track Records ISSN: 2157-8990.

Chart created by C. Mick using Microsoft Excel, 2022.

Figure 1 above provides a visual testament to the contribution of plant breeders to the farmer’s success. From 1888 to 2018, yield per acre of wheat in the U.S. rose from around 13 bushels to 45 bushels with a surge of improvement from 1940 to 2018. From the 1860s to the 1930s, farmers in the USA grew the same varieties of wheat that their relatives grew in Europe or Asia. The old cultivars are sometimes called landraces. Landraces have been domesticated and subjected to natural selection in farmer’s fields from the part of the world where the crop species was first planted for a purpose or first adapted by farmers. They saved seed to grow the next year on their farms from what they harvested the previous year. Some farmers traded seed varieties with neighbors or relatives based on the success of the crop. The average yields fluctuated up and down, depending on the stress or lack of stress in that year’s growing season. However, during that time, the average yield trend that we observe in the graph is flat.  Farmers were not increasing the yields on their farms.  Starting in the 1940’s, the yield trend changed. Plant breeders working for public institutions and seed companies began to work on developing new varieties. These varieties were then chosen by farmers to replace the old landraces. The trend in yield improvement continues today.

Plant breeders work closely with farmers to identify the goals they will have in their breeding program. One goal of a wheat breeder, for example, is to create new varieties that can resist the diseases caused by changing populations of pathogens. An average seed company might sell a couple hundred cultivars across the state, nation, or even worldwide. The plant breeder will develop new cultivars. However, these cultivars must meet the farmer’s expectations and grow better on their farm than the cultivars the farmer is currently growing.  The breeder, therefore, is motivated to meet the farmer’s standard before they are ready to release one of their new cultivars for seed production. A crop that is widely grown has been successful in being productive on many farmers fields. Farmers have relied on the cultivars available from this species to grow well. This prior success requires an intense process for developing new, improved cultivars.

Plant breeding is the science of improving crops for human benefit. Humans could seek anything from enhanced flavor in coffee beans to an appealing color of flowers in their pots of impatiens, to improved disease resistance in soybeans. While the general series of steps remain the same, plant breeding is not a one-size-fits-all pathway. There is a basic template plant breeders follow that they customize for each plant species to optimize their chances of identifying improved cultivars. Therefore, plant breeders will carefully implement practices based on research and theory, and continually search for ways to improve selection methods with new scientifically tested methods.