Heat stress on northern highbush blueberry in Oregon and Washington, USA

The Pacific Northwestern (PNW) region of North America is a primary production area for northern highbush blueberries (NHB, Vaccinium corymbosum L.). Historically, most of this production has been in the moderate maritime parts of the region. However, innovative blueberry growers are expanding production acreage into areas that routinely reach higher than ideal summer temperatures. Breeding programs seek to address the needs of this broader production area when developing new cultivars. Four sites representing unique blueberry growing regions in the PNW were chosen as trial locations for this study. Corvallis, Oregon, and Lynden, Washington, have a maritime climate, tending to be moist with moderate temperatures for most of the year. Myrtle Creek, Oregon, and Prosser, Washington, have lower relative humidity with large summer and winter temperature fluctuations. Progeny of 15 NHB breeding families and the eight parental cultivars used to create them were planted at these four sites. Our objective was to determine the response of the genotypes in our blueberry populations to differences in the environment, particularly to heat stress, across the sites. However, in 2021, our first year of data collection, a historic heat event called a heat dome occurred during the early and mid-ripening process of blueberry fruits, affecting all four locations across the region. We monitored the effect of this event on fruit sunburn, fruit texture, foliar tip burn, and leaf scorch at the four trial locations. Differences among the breeding families and across the four locations in response to the heat dome were present at all four sites in 2021 for fruit sunburn, foliar tip burn, and foliar leaf scorch. For fruit texture, the relationships between the interactions of breeding family and location were inconclusive.

This paper comes with 1 supplemental table. Click here to download the file containing the supplemental data in .xlsx format.