Heated Plot Experiments Reveal Link between Warmer Early Winters and Lower Crop Yields
Published:08 Oct.2022 Source:John Innes Centre
Innovative experiments using temperature-controlled field plots have helped to explain the link between early winter temperatures and yield in some of our most marketable arable crops.
Laboratory and in-field technology enabled the team of researchers from the John Innes Centre to simulate full growing seasons and establish that chilling is important in late November/early December because it promotes growth during early floral development of the crop.
They showed that oilseed rape plants can undergo a developmental phase known as flower bud dormancy if the winter temperature is too warm. This physiological process occurs as the microscopic, newly formed buds lie inactive waiting for low temperatures to signal growth and is well understood in perennial plants which grow year after year.
This development stage was not known to exist in annual crops; those that complete their life cycle in one growing season.
Oilseed rape plants that were chilled at this key developmental stage developed faster and were higher yielding, producing more seeds per pod. Conversely plants grown in warmer conditions grew slowly and were lower yielding.
Professor Steve Penfield, a group leader at the John Innes Centre said: "It was surprising to find that winter annuals have this flower bud dormancy -- no one has ever suggested that this mechanism is important to flowering time control in annual plants. Our experiments further show that if flower buds experience warmer than average temperatures then growth slows down and plants produce aberrant flowers and low yield. Conversely, we know that if plants get chilled at this stage this promotes faster growth and higher yield."
Previous studies have shown a strong correlation between late November-early December temperatures and yield in crops such as oilseed rape, which are winter annuals, planted in the autumn and harvested the following summer.
Colder temperatures during this weather window are linked to higher yields, while warmer temperatures result in lower yields. The differences in conditions during this important weather window account for a variation of up to 25% of total yield.
Understanding the reasons behind the statistical correlations between climate and yield is important for predicting the impact of climate change on crop production and could be used to develop strategies to adapt the crop to produce higher yields with warmer winters.