Submitted to: Journal of Agronomy and Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2018
Publication Date: 5/30/2018
Citation: Landry, E.J., Hu, J. 2018. Increasing pre-acclimation temperature reduces the freezing tolerance of winter-type faba bean (Vicia faba L.). Journal of Agronomy and Crop Science. https://doi.org/10.1111/jac.12289.
DOI: https://doi.org/10.1111/jac.12289 Interpretive Summary: Autumn-sown winter-type faba bean has been shown to have a yield advantage over spring sowing . However, winter survival is unpredictable in locations where winter temperatures remain below -15 °C for an extended period of time . Therefore, understanding the mechanisms of cold acclimation and freezing tolerance in order to develop populations with improved winter hardiness or provide more accurate production recommendations remains necessary. This paper reports the experimental results of how the prevailing temperature during emergence and seedling development, i.e. cold acclimation, influences freezing tolerance. It also suggests a cold acclimation protocol for optimizing freezing tolerance of winter-type faba bean seedlings would be four weeks at 10/5 °C (day/night temperature) followed by four weeks at 12/0 °C.
Technical Abstract: Autumn-sown winter-type faba bean (Vicia faba L.) has been shown to have a yield advantage over spring sowing. Still, adoption of this overwintered pulse crop remains limited in temperate locations, due to inadequate winter hardiness. This research sought to understand how the prevailing temperature during emergence and seedling development, i.e. cold acclimation, influences freezing tolerance. Seedlings grown under a ‘warm’ 17/12 °C (day/night) environment were initially less freezing tolerant than those grown under a ‘cold’ 12/5 °C temperature treatment. Root and stem tissues were particularly sensitive to air temperature above 15 °C, however, root tissues remained sensitive throughout the duration of cold acclimation, regardless of temperature, showing no tolerance to temperatures below -7 °C. Based on these experimental results the necessary cold acclimation protocol for optimizing freezing tolerance of winter-type faba bean seedlings would be four weeks at 10/5 °C followed by four weeks at 12/0 °C. Due to climate variability however, identification of adaptive genotypes using artificial environments remains a challenge. Screening for germplasm with improved root freezing tolerance or further understanding basal regrowth from freeze injured seedlings would improve yield stability by limiting overwintering stand loss.