Effects of Soil Moisture, Cultivar, and Postharvest Handling on Pillowy Fruit Disorder in Cucumber

Abstract

Two experiments (1989 and 1990) were designed to characterize the response of cucumber (Cucumis sativus L.) plants with different leaf types [normal leaf (LL) vs. little leaf (ll)] to high soil moisture tension (SMT) and to determine whether hydrocooling would reduce the severity of pillowy fruit disorder (PFD). Comparisons were made among nine cultivars (7 LL and 2 ll) for aboveground vegetative and fruit response, and between two irrigation regimes. High SMT generally caused increased wilt ratings and stomatal conductance and decreased plant dry weight. PFD severity of fruit from watered plots was less [61% (Expt. 1, 1989) and 26% (Expt. 1, 1990)] than of fruit harvested from plots in which water was withheld. The response of the two ll cultivars to moisture stress differed depending on environmental conditions. Increased PFD severity was associated with increased temperature, lower relative humidity (RH), and excluding hydrocooling during postharvest handling. Of the four storage treatments examined, hydrocooling to ≈8.5C then storage at 15C and 85% RH for 4 days produced fruit with the least PFD symptoms. Fruit of `Carolina' (LL) exhibited the highest PFD ratings, while those of `Calypso' (LL) were consistently low compared to other cultivars. Processors can lower PFD incidence and severity by ensuring that adequate moisture is available to plants during fruit enlargement and that harvested fruit are hydrocooled before shipping and storage.