| dc.description.abstract | Drought is one of the most detrimental natural causes leading to yield loss in crops across
the globe. With increasing severity and frequency of drought events, it is imperative to identify
and breed for cultivars that can withstand periods of water deficit. In blueberry (Vaccinium sp.),
drought is especially adverse due to a shallow root system which lacks root hairs. The purpose of
this study was to identify common responses of blueberry to drought in addition to finding
cultivars with superior traits in response to water deficit. In the southeastern United States, both
rabbiteye (Vaccinium virgatum) and southern highbush (Vaccinium corymbosum L. interspecific
hybrids) blueberries are commonly cultivated due to their low chill requirements. Previous
studies have highlighted on the ability of the rabbiteye ecotype to withstand several abiotic
stresses including drought, while southern highbush is more well-known for its superior berry
quality.
In order to examine the effects of drought on both southern highbush and rabbiteye
blueberries, seven cultivars were chosen for evaluation: Misty, Star, Suziblue (SHB), Brightwell,
Vernon, Powderblue, and Climax (RE). Four-year-old plants of all seven cultivars were
subjected to a drought period of 36-days in the spring of 2023 at EV Smith Research Station in
Tallassee, AL. Throughout the drought, plants were monitored for overall plant health,
physiological activity, yield, and fruit quality.
Drought stress was found to significantly decrease photosynthesis, stomatal conductance,
electron transport rate, leaf relative water content, specific leaf area, chlorophyll content, Jmax,
yield, average berry weight, and malic acid content of berries. Alternatively, water stress was
found to significantly increase Brix, polyphenol, and berry firmness. Star and Misty were
identified as the most drought tolerant cultivars based on high yield and average berry weight in addition to high levels of gas exchange under drought stress. Alternatively, Powderblue, Vernon,
and Suziblue were found to be the most susceptible to drought. Brightwell was found to have
intermediate tolerance in comparison to other cultivars. In the future, it would be valuable to
study post-drought root morphology in addition to studying genetic factors that may play a role
in blueberry drought tolerance | en_US |
