Differential Response of Wheat Cultivars to Components of the Freezing Process in Saturated Soil

Abstract

Winter wheat (Triticum aestivum L. em. Thell.) is sown in the autumn and harvested the following summer, and therefore must survive subfreezing temperatures for several months. Because of autumn rains and winter snows, the plants usually are subjected to these subfreezing temperatures while growing in saturated soil. As the plants freeze, they are subjected to freezing episodes that may vary in the cooling rate, the minimum temperature, the time at the minimum temperature, and the warming rate as the freezing episode ends. We investigated the impact of each of these freezing process components on the ability of 22 winter wheat cultivars to survive freezing in saturated soil using logistic regression and cluster analyses. The 22 cultivars formed three distinct groups when clustered on the odds ratios associated with the freezing process components. The distinctiveness of the three clusters indicated the cultivars within each cluster responded differently to the freezing process than cultivars in the other clusters. Some cultivars occurred in different clusters but had equal levels of freezing tolerance. We conclude the logistic regression/clustering analysis identified cultivars that differed in the mechanisms used to respond to freezing stress, and that equal levels of freezing tolerance can be attained through these different mechanisms. It may be possible to improve winterhardiness by genetically combining these disparate responses to the freezing process components.

Cytoplasmic and nuclear genetic components of membrane stability of winter wheat plants exposed to sub‐zero temperatures

“…This effect was most apparent from the increased freezing tolerance in the progeny of the cultivar Tiber when crossed as female to Hatton, Lewjain, or Masami (Figure a). This result was predicted in previous work (Skinner & Bellinger, ) in which cultivars were clustered according to their responses to various components of the freezing process. In that study, Hatton, Lewjain and Masami were grouped into one cluster while Tiber was in a separate cluster (see Figure in Skinner & Bellinger, ).…”

“…This result was predicted in previous work (Skinner & Bellinger, ) in which cultivars were clustered according to their responses to various components of the freezing process. In that study, Hatton, Lewjain and Masami were grouped into one cluster while Tiber was in a separate cluster (see Figure in Skinner & Bellinger, ). It was hypothesized that cultivars in separate clusters may use different mechanisms to respond to cold, and thus crossing cultivars from two different clusters may result in favourable combinations of response mechanisms (Skinner & Bellinger, ).…”

Snowed in for survival: Quantifying the risk of winter damage to overwintering field crops in northern temperate latitudes

“…In addition, the application of more diverse experimental designs in the laboratory would provide data on the response to short-term exposure to low temperature compared to prolonged exposure to milder ones, as common under field conditions. A few examples of such experiments are the results of Skinner and Bellinger (2011) and Gusta et al (1997) but more research of this type is warranted to strengthen the correspondence between laboratory results and field performances. Data of this sort would enable us to more fully exploit existing datasets on LT50.…”

“…Exposure to low temperature A plant's ability to withstand low temperature has been characterized by several methods under a variety of experimental conditions. Different measures or indices of crop hardiness have been employed: under field conditions, the percentage of survival and the Field Survival Index (Fowler and Gusta, 1979); under controlled conditions, the lethal temperature for 50% of the individuals following a short exposure, LT 50 (e.g., Chen et al, 1983), and cumulated degree minutes for prolonged exposures to milder, sub-zero temperatures (Skinner and Bellinger, 2011). Although Field Survival Index and LT 50 have been shown to be correlated (Brule-Babel and Fowler, 1989), the different assessment methods, combined with different experimental conditions, often result in inconsistent variety rankings (Gusta and Wisniewski, 2013;Skinner and Bellinger, 2011).…”

“…The potential damage stemming from long-term exposures to low temperatures has been assessed by means of 'cumulated degree days' (or minutes as in Skinner and Bellinger, 2011), i.e., the total time spent by the plant below a base temperature T base , often set at 0 • C). The cumulated degree days 'summarize' the temperatures to which the crop is exposed throughout the winter and greatly facilitates the comparison of different climates (and hence locations).…”