Field pea cardinal temperatures, growth and vigor traits of winter- and spring-adapted germplasm at germination and seedling stages

Authors: Adams, Curtis; Cosner, Juniper

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2025
Publication Date: 7/1/2025
Citation: Adams, C.B., Cosner, J.M. 2025. Field pea cardinal temperatures, growth and vigor traits of winter- and spring-adapted germplasm at germination and seedling stages. Scientific Reports. 15. Article 21759. https://doi.org/10.1038/s41598-025-06342-w.
DOI: https://doi.org/10.1038/s41598-025-06342-w

Interpretive Summary: In biology there is a concept known as “cardinal temperatures,” which are the minimum (or base), optimum, and maximum temperatures for growth and development of an organism at any given lifecycle stage. These are represented by Tb, To, and Tm, respectively. Cardinal temperatures are used in plant growth modelling and many other applications. There are few existing estimates of the cardinal temperatures for seed germination and seedling growth of peas, with variable results, and almost no understanding of how these traits vary among pea varieties or classes. The objective of this controlled-environment study was to provide improved cardinal temperature estimates and understanding of field pea seedling responses to temperature. Interestingly, there were no collective differences between winter- and spring-adapted food-grade field peas in cardinal temperatures. Overall estimates were -0.98°C for Tb, 27.5°C for To, and 37.5°C for Tm. Austrian winter peas, known for exceptional cold hardiness, had lower To (25.7°C) and Tm (36.1°C) than the food-grade peas. Metrics of seedling vigor and growth (germination rate and percentage, shoot elongation) were substantially higher for Austrian peas than the food peas and may be a source of genetics for breeding these traits. Considering both cardinal temperatures and germination rate, the average thermal time requirements for 50% germination were 31.0, 46.6, and 55.9°Cd for AWP, winter food, and spring food peas, respectively. These results provide improved metrics and understanding of field pea seedling responses to temperature for modelling and other applications.

Technical Abstract: There are few estimates of cardinal temperatures [Tb (base), To (optimal), Tm (maximum)] for pea (Pisum sativum L.) seed germination and seedling growth traits, with variable results, and there is almost no understanding of how these traits vary among pea varieties or classes. The objective of this controlled-environment study was to compare these among multiple varieties of food-grade winter and spring field peas and Austrian winter pea (AWP). Contrary to hypothesized outcomes, there were no collective differences in any of the three cardinal temperatures between winter- and spring-adapted food-grade field peas. Overall estimates were - 0.98 °C for Tb, 27.5 °C for To, and 37.5 °C for Tm. AWP, known for exceptional cold hardiness, contrasted from the food peas in having lower To (25.7 °C) and Tm (36.1 °C). Metrics of seedling vigor and growth (germination rate and percentage, shoot elongation) were markedly higher for AWP than the food peas. The food-grade winter pea seeds were collectively somewhat more vigorous than the spring peas. Considering both cardinal temperatures and germination rate, the average thermal time requirements for 50% germination were 31.0, 46.6, and 55.9 °Cd for AWP, winter food, and spring food peas, respectively. These results provide improved metrics and understanding of field pea seedling responses to temperature.There are few estimates of cardinal temperatures [Tb (base), To (optimal), Tm (maximum)] for pea (Pisum sativum L.) seed germination and seedling growth traits, with variable results, and there is almost no understanding of how these traits vary among pea varieties or classes. The objective of this controlled-environment study was to compare these among multiple varieties of food-grade winter and spring field peas and Austrian winter pea (AWP). Contrary to hypothesized outcomes, there were no collective differences in any of the three cardinal temperatures between winter- and spring-adapted food-grade field peas. Overall estimates were - 0.98 °C for Tb, 27.5 °C for To, and 37.5 °C for Tm. AWP, known for exceptional cold hardiness, contrasted from the food peas in having lower To (25.7 °C) and Tm (36.1 °C). Metrics of seedling vigor and growth (germination rate and percentage, shoot elongation) were markedly higher for AWP than the food peas. The food-grade winter pea seeds were collectively somewhat more vigorous than the spring peas. Considering both cardinal temperatures and germination rate, the average thermal time requirements for 50% germination were 31.0, 46.6, and 55.9 °Cd for AWP, winter food, and spring food peas, respectively. These results provide improved metrics and understanding of field pea seedling responses to temperature.